NASDAQ: TPST

Recent Developments

Strategic Acquisition of Dual-Targeting CAR-T Programs

On November 19, 2025, we executed an Asset Purchase Agreement (the “Asset Purchase Agreement”) with Erigen LLC, a Delaware limited liability company (“Erigen”), and Factor Bioscience Inc., a Delaware corporation (together with Erigen, “Sellers”), pursuant to which Sellers agreed to sell and transfer to the Company all right, title and interest of Sellers, worldwide outside of China, Russia, India, and Turkey, in and to all of the assets primarily related to (a) the autologous BCMA/CD19 dual-targeting CAR T-cell therapy known as TPST-2003 currently being evaluated in a Phase 1/2a clinical study in patients with rrMM, a Phase 1/2 investigator-initiated trial (“IIT”) in patients with rrMM, and a Phase 1 clinical study in patients with POEMS Syndrome (“POEMS”), a rare blood disorder caused by abnormal plasma cells, (b) the autologous CD70/CD70 dual-targeting CAR T-cell therapy known as TPST-2206, (c) the allogeneic BCMA/CD19 dual-targeting CAR T-cell therapy with a gene edit in the TRAC locus that inactivates the T cell receptor known as TPST-3003, and (d) the allogeneic CD70/CD70 dual-targeting CAR T-cell therapy with a gene edit in the TRAC locus that inactivates the T cell receptor known as TPST-3206 (collectively referred to herein as the “Assets”), in exchange for an aggregate purchase price of 8,268,495 shares of our common stock issued to Erigen on behalf of both Sellers.

Pursuant to the Asset Purchase Agreement, at Closing we assumed Erigen’s rights and obligations under each of the Novatim License Agreement and the Restated Factor License Agreement (each as defined below under “—License and Collaboration Agreements”). Under the Novatim License Agreement, we obtained an exclusive license to specified patents and know-how in all fields worldwide, but excluding Greater China, India, Turkey, and Russia, to exploit the TPST-2003 and TPST-2206 programs and allogeneic CAR-T therapies based on the TPST-2003 and TPST-2206 programs. We also received a right of first negotiation to negotiate a license to exploit allogeneic CAR-T therapies and in vivo CAR-T therapies in Greater China.

Under the Restated Factor License Agreement, we obtained an exclusive license to specified patents in all fields worldwide, but excluding Greater China, India, Turkey, and Russia, to exploit the TPST-3003 and TPST-3206 programs. The Restated Factor License Agreement also establishes a Joint Steering Committee for the purposes of discussing and coordinating collaboration opportunities and serving as a forum for information sharing.

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On February 3, 2026, we completed the acquisition of the Assets (the “Closing”) under the Asset Purchase Agreement (the “Asset Acquisition”) and issued to Erigen 8,268,495 shares of our common stock (the “Share Issuance”).

Following the transaction, we are prioritizing a capital-efficient development strategy across our portfolio. This approach includes seeking partner support, external funding sources, and staged investment decisions based on clinical data generation and regulatory feedback. We expect this strategy to allow us to pursue parallel development of multiple programs while managing internal cash resources and extending our operational runway.

Our Pipeline

Our product development pipeline consists of the following product candidates:

1. “RCC” renal cancer; “CCA” cholangiocarcinoma; “FPI” First Patient In; “SLE” lupus.

CAR-T Cell Therapy Programs

Our cell therapy programs expand our oncology pipeline with a portfolio of next-generation CAR-T product candidates designed to potentially address the limitations of currently available cell therapies and broaden the applicability of CAR-T therapy across hematologic malignancies and solid tumors. Our programs include autologous, allogeneic and in vivo approaches utilizing dual-targeting strategies.

Our lead cell therapy product candidate, TPST-2003, is an autologous dual-targeting CAR-T therapy directed against CD19 and BCMA for the treatment of rrMM. In addition, our pipeline includes TPST-2206, a dual-targeting CAR-T therapy directed against CD70 for solid tumors, as well as allogeneic dual-targeting CAR-T programs, including TPST-3003 and TPST-3206, and an in vivo dual-targeting CAR-T program, TPST-4003.

We believe our cell therapy portfolio has the potential to address tumor heterogeneity and antigen escape and to improve access through scalable manufacturing approaches. We are evaluating these programs across hematologic malignancies, solid tumors, and immunology indications.

Small-Molecule Programs

Our small-molecule programs consist of two clinical-stage product candidates with the potential to be first-in-class to treat a wide range of cancers. Our programs include: amezalpat (previously known as TPST-1120), that is poised to begin a pivotal study in

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first-line HCC, subject to business development discussions, and TPST-1495, which we expect will enter Phase 2 development in 2026. We believe both amezalpat and TPST-1495 are the first clinical-stage molecules designed to inhibit their respective targets.

Amezalpat (TPST-1120)

Amezalpat is an oral, small molecule, selective antagonist of peroxisome proliferator-activated receptor alpha (“PPARα”) being developed for the treatment of first-line unresectable or metastatic HCC. Amezalpat remains Phase 3-ready in first-line HCC, supported by global regulatory alignment and positive randomized Phase 2 data. We plan to pursue business development discussions to advance pivotal development.

In June 2024, we unveiled positive survival data from the global randomized Phase 1b/2 clinical study demonstrating that amezalpat delivered a six-month improvement in median overall survival (“OS”) with a hazard ratio (“HR”) of 0.65 when combined with atezolizumab and bevacizumab in comparison to atezolizumab and bevacizumab alone, the standard of care, in the first-line treatment of patients with unresectable or metastatic HCC. Additionally, the survival benefit was preserved across key subpopulations, including patients with PD-L1 negative disease and β-catenin mutated disease, consistent with amezalpat’s proposed mechanism of action targeting both tumor cells directly and the patient’s immune system.

In August 2024, we announced the successful completion of our end-of-Phase 2 meeting with the U.S. Food and Drug Administration (“FDA”) regarding the development of amezalpat for the treatment of first-line unresectable or metastatic HCC. The FDA provided positive feedback on the pivotal Phase 3 clinical trial design, which closely mirrors the positive randomized Phase 2 study. The planned Phase 3 trial is designed to use the current Phase 2 amezalpat dose and schedule in combination with atezolizumab and bevacizumab and will be compared to atezolizumab and bevacizumab alone, the standard of care. The primary endpoint of the trial will be OS. Additionally, the FDA agreed to a pre-specified early efficacy analysis, which, if met, would potentially reduce the time to primary read-out by up to eight months.

In November 2024, we received a “Study May Proceed” letter from the FDA, authorizing the initiation of our pivotal Phase 3 trial. In January 2025, the FDA granted Orphan Drug Designation (“ODD”) for amezalpat for the treatment of patients with HCC. In February 2025, the FDA granted Fast Track Designation (“FTD”), underscoring the agency’s recognition of the urgent need for new treatment options for HCC. In addition to receiving ODD from the FDA, in June 2025, the European Medical Agency (“EMA”) also granted ODD for the treatment of patients with HCC. These designations provide potential regulatory benefits, including increased engagement with the FDA, eligibility for accelerated approval and priority review, and, for ODD, potential market exclusivity upon approval.

TPST-1495

Our second clinical-stage small-molecule program, TPST-1495, is a novel, dual antagonist of the EP2 and EP4 receptors of prostaglandin E2 (“PGE2”), a pathway implicated in multiple cancers. Our development strategy for TPST-1495 includes evaluation in FAP, a rare genetic disorder that significantly increases the risk of gastrointestinal cancers and for which there are no approved systemic therapies. Given that prostaglandin signaling is also implicated in FAP and based on positive preclinical data in a relevant mouse model, we believe there is strong mechanistic support for this approach.

In March 2025, the CP-CTNet received a “Study May Proceed” letter from the FDA, authorizing the initiation of a NCI-funded Phase 2 clinical trial evaluating TPST-1495 in patients with FAP. This trial, run by CP-CTNet and financially supported by the NCI’s Division of Cancer Prevention, underscores the urgent need for innovative cancer prevention strategies in high-risk patient populations. The Phase 2 study is expected to begin in 2026.

Strategy

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Our objective is to build a capital-efficient oncology company by advancing a pipeline of advanced CAR-T cell therapy and small-molecule product candidates through clinical development while maintaining disciplined capital allocation. Our strategy includes the following components:

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Advance TPST-2003 through upcoming clinical milestones

We plan to continue development of TPST-2003 with near-term clinical data expected from an ongoing Phase 1/2a clinical trial in China. We anticipate initiation of a registrational Phase 2b in China by the end of 2026, with interim data expected in 2027. Development activities in China are funded by our strategic partner, Novatim Immune Therapeutics (“Novatim”), providing access to pivotal data while preserving internal capital.

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Expand the portfolio with allogeneic and in vivo CAR-T development

TPST-3003 and TPST-4003 represent our first allogeneic and in vivo CAR-T programs, respectively, and are each designed to extend the TPST-2003 biology into potentially more scalable and patient-friendly modalities. We expect to advance these programs through preclinical development and evaluate potential clinical entry through strategic partner-funded IIT clinical studies in the near term.

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Position amezalpat for pivotal development through business development

Amezalpat remains Phase 3-ready in first-line HCC, supported by global regulatory alignment and positive randomized Phase 2 data. We plan to pursue business development discussions to advance pivotal development.

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Advance TPST-1495 through externally funded clinical development

We plan to initiate a Phase 2 study of TPST-1495 in FAP, with first patient enrollment expected in 2026. The study is expected to be funded by the NCI and conducted through the Cancer Prevention Clinical Trials Network, enabling advancement with limited internal capital deployment.

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Advance a diversified next-generation CAR-T pipeline

We plan to progress additional dual-targeting CAR-T programs that broaden the platform across modalities and indications, including:

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TPST-2206: a dual-targeting CD70/CD70 CAR-T

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TPST-3206: an allogeneic dual-targeting CD70/CD70 CAR-T

CAR-T Cell Therapy

Background on Cancer and CAR-T Cell Therapy

Cancer remains a leading cause of death worldwide and continues to represent a significant unmet medical need despite advances in surgery, radiation, targeted therapies and immunotherapies. Hematologic malignancies, including multiple myeloma and certain lymphomas and leukemias, often have limited treatment options in relapsed or refractory settings, where outcomes remain poor. Similarly, many solid tumors, including renal cell carcinoma, remain difficult to treat in advanced stages, particularly following progression on standard therapies.

Adoptive cell therapy, including CAR-T, has emerged as an important treatment modality in oncology. CAR-T therapy typically involves collecting a patient’s T cells, genetically modifying them to express engineered receptors that recognize tumor-associated antigens, expanding the modified cells ex vivo, and infusing them back into the patient to target cancer cells. CAR-T therapies have demonstrated meaningful clinical responses in certain hematologic malignancies and have led to multiple regulatory approvals. However, currently available CAR-T therapies face limitations, including antigen escape, limited durability of response, manufacturing complexity, safety risks and reduced efficacy in certain patient populations.

Next-generation CAR-T approaches are being developed to address these limitations. These include dual-targeting CAR-T therapies designed to recognize multiple tumor antigens, which may help mitigate antigen escape and improve durability, as well as allogeneic and in vivo CAR-T therapies designed to improve manufacturing scalability and patient access.

CD19/BCMA Dual-Targeting CAR-T Therapy in rrMM

Our lead cell therapy product candidate, TPST-2003, is an autologous dual-targeting CAR-T therapy directed against CD19 and BCMA for the treatment of rrMM. Multiple myeloma is a hematologic malignancy characterized by the clonal proliferation of

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malignant plasma cells in the bone marrow. Despite advances in treatment, including proteasome inhibitors, immunomodulatory agents and monoclonal antibodies, patients with relapsed or refractory disease often experience progressive disease and poor outcomes. While currently approved CAR-T therapies targeting BCMA have demonstrated clinical benefit in rrMM, disease relapse remains common, and treatment options following relapse are limited.

BCMA is a cell surface receptor that is preferentially expressed on mature B cells and plasma cells, including malignant plasma cells in multiple myeloma, and plays an important role in plasma cell survival and proliferation. As a result, BCMA has emerged as a clinically validated target for CAR-T therapy in multiple myeloma. However, resistance to BCMA-targeted therapies has been observed, including through antigen loss or downregulation, which may contribute to disease relapse. CD19 is a B-cell lineage antigen that is expressed earlier in B-cell development and has been implicated in certain subsets of multiple myeloma, including progenitor or disease-propagating cell populations. Targeting both CD19 and BCMA simultaneously may help address tumor heterogeneity and reduce the risk of antigen escape.

Preclinical and clinical studies reported in the scientific literature have suggested that dual-targeting approaches may improve depth and durability of response compared to single-target therapies. This body of literature provides the scientific rationale for the development of dual-targeting CAR-T therapies such as TPST-2003 for the treatment of patients with rrMM.

TPST-2003: Dual-Targeting BCMA/CD19 Autologous CAR-T Therapy

TPST-2003 is an autologous, dual-targeting CAR-T therapy designed to target both BMCA and CD19. TPST-2003 is being developed for the treatment of rrMM.

Mechanism of Action

TPST-2003 incorporates a proprietary parallel dual-targeting CAR architecture designed to recognize both BCMA and CD19.

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Figure: TPST-2003 parallel dual-targeting CAR construct targeting BCMA and CD19.

Scientific Rationale for Dual-Targeting CAR Architecture

CAR-T therapies function by engineering a patient’s T cells to express receptors that recognize tumor-associated antigens. Most currently available CAR-T therapies in multiple myeloma target a single antigen, typically BCMA. While these therapies can produce deep responses, relapse may occur when tumor cells reduce or lose expression of that antigen or when heterogeneous tumor populations express different surface markers.

By enabling recognition of two distinct targets, TPST-2003’s dual-targeting approach is intended to:

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Reduce the likelihood of tumor escape through antigen loss;

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Improve targeting of heterogeneous tumor populations; and

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Potentially enhance persistence of anti-tumor activity.

Clinical responses have been observed across multiple dose levels and study settings to date; however, additional follow-up and larger studies will be required to determine the reproducibility and durability of these findings.

The same dual-targeting CAR architecture forms the basis of additional programs in our pipeline, including TPST-3003, an allogeneic CAR-T program, and TPST-4003, an in vivo CAR-T approach.

The clinical studies described below were designed to evaluate the safety and clinical activity of this dual-targeting approach, including in heavily pretreated patients.

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Clinical Study Design

TPST-2003 is currently being evaluated in a Phase 1/2 IIT clinical study and a REDEEM-1 Phase 1/2a trial, in each case in patients with rrMM, including patients who have received multiple prior lines of therapy. The IIT and REDEEM-1 Phase 1/2a trial are being conducted by investigators affiliated with Novatim and are being funded by Novatim.

To be eligible for the Phase 1/2 IIT clinical study and the REDEEM-1 Phase 1/2a trial, patients must have rrMM and must have received at least one prior line of therapy. The Phase 1/2 IIT clinical study and the REDEEM-1 Phase 1/2a trial are primarily focused on evaluating the safety and tolerability of TPST-2003, as well as determining the clinical recommended dose of TPST-2003. Accordingly, the primary endpoints of the Phase 1/2 IIT clinical study and the REDEEM-1 Phase 1/2a trial are the assessment of adverse events (“AEs”) and serious adverse events (“SAEs”). The secondary endpoints cover both PK and PD assessments, examining how the therapy behaves and acts within the body, as well as a set of efficacy measures including: progression-free survival (“PFS”); overall response rate (“ORR”); complete response (“CR”); strict complete response (“sCR”); duration of response; disease control rate (“DCR”), minimal residual disease (“MRD”); and OS.

Clinical Development Program

Clinical experience with TPST-2003 to date consists of early-phase studies, including the ongoing Phase 1/2 IIT and the ongoing REDEEM-1 Phase 1/2a trial. As of the January 31, 2026 data cutoff, a total of 36 patients with rrMM had received one infusion of TPST-2003 across these two studies:

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24 patients treated in the Phase 1/2 IIT; and

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12 patients treated in the REDEEM-1 Phase 1/2a trial.

Patients enrolled in REDEEM-1 had received a median of four prior lines of therapy.

Among the six patients evaluable for efficacy as of the January 31, 2026 data cutoff in REDEEM-1, including three treated at dose level 1 (1 x 106cells/kg) and three treated at dose level 2 (2 x 106 cells/kg), the CR rate was 100% (6/6) based on International Myeloma Working Group criteria.

Across both studies, among 25 evaluable patients with measurable disease at baseline, the ORR was 100% (25/25). These findings are based on a limited number of patients to date, and additional follow-up will be required to determine clinical benefit.

Safety Profile Observations to Date

The safety profile observed in REDEEM-1 has included:

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No Grade 3 or higher cytokine release syndrome (“CRS”);

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One patient treated at the highest dose level experiencing low-grade immune effector cell-associated neurotoxicity syndrome (“ICANS”); and

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No Grade 3 or higher ICANS.

We believe that the observed safety profile together with the consistency of responses observed in the REDEEM-1 trial support our plan to accelerate our development timeline and meet with the FDA to discuss initiating a U.S. registrational study later this year.

Durability of Response Observed in Earlier Study

We believe clinical findings from the REDEEM-1 study appear generally consistent with the earlier IIT. In the IIT, among 19 evaluable patients with measurable disease at baseline:

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ORR was 100% (19/19);

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CR rate was 89.5% (17/19); and

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At the highest evaluated dose level, CR was observed in 100% (5/5).

The IIT also reported durable disease control, including:

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Median PFS of 23.1 months across all patients;

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Median PFS of 23.1 months in patients with extramedullary disease (“EMD”); and

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MRD negativity at month 12 in all evaluable patients (5/5).

Patients with EMD are often associated with poorer outcomes and shorter disease control in rrMM. We are continuing to evaluate the durability of response observed in these studies.

TPST-2003 is also currently being evaluated in an ongoing Phase 1 clinical trial in patients with POEMS, a rare blood disorder caused by abnormal plasma cells. The POEMS trial is being conducted by investigators affiliated with Novatim and is being sponsored by Novatim.

Development Plans

We expect to present additional results from the REDEEM-1 study and updated IIT data at a scientific meeting in 2026. Based on data generated to date, we plan to submit an Investigational New Drug (“IND”) application to the FDA and, subject to regulatory clearance, may initiate a U.S. registrational study in 2026.

Pre-Clinical Programs

TPST-3003: Allogeneic Dual-Targeting CD19/BCMA CAR-T

Allogeneic CAR-T cell therapies are manufactured from donor cells, unlike autologous CAR-T cell therapies, which are manufactured from the patient’s own cells. Allogeneic CAR-T cell therapies thus have the potential to offer an off-the-shelf alternative to autologous products, that may reduce manufacturing complexity, potentially increasing availability to patients.

To manufacture an allogeneic CAR-T cell therapy, the T-cell receptor of the donor cells is typically eliminated (“knocked out”), to reduce the chance that the donor cells may nonspecifically attack the patient’s healthy cells (“graft-vs-host activity”).

TPST-3003 is an allogeneic dual-targeting CD19/BCMA CAR-T product that we are developing for the treatment of rrMM. Because TPST-3003 uses the same dual-targeting architecture as TPST-2003, we believe that TPST-3003 has the potential to maintain the same positive safety and efficacy profile that we have observed in early-stage clinical studies of TPST-2003, while reducing manufacturing complexity and potentially increasing availability to patients. We are planning to evaluate TPST-3003 in patients with rrMM in an strategic partner-sponsored IIT, with enrollment potentially beginning in the third quarter of 2026.

TPST-4003: In-vivo Dual-Targeting CD19/BCMA CAR-T

In vivo CAR-T therapies typically comprise nucleic acid molecules that encode a CAR sequence and which are formulated for delivery to a patient’s T cells in the patient’s body. Most typically, an in vivo CAR-T therapy consists of one or more mRNA molecules encoding a CAR sequence, formulated as a lipid nanoparticle, which is designed to target delivery to a specific type of cell in a patient’s body (e.g., a T cell that expresses the CD8 protein). Because in vivo CAR-T therapies generally do not require manipulating either the patient’s or a donor’s cells as part of the manufacturing process, they have the potential to reduce manufacturing complexity as compared to both autologous and allogeneic CAR-T approaches. Because of the potential advantages of in vivo CAR-T therapies, these approaches are being explored for potential treatment of immunology indications, including lupus, in addition to cancer.

TPST-4003 is an in vivo dual-targeting CD19/BCMA CAR-T product that we are developing for the treatment of lupus. Because TPST-4003 uses the same dual-targeting architecture as TPST-2003, we believe that TPST-4003 has the potential to achieve a

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favorable safety and efficacy profile as compared with single-targeting approaches. We are planning to evaluate TPST-4003 in patients with lupus in a strategic partner-sponsored IIT, with enrollment potentially beginning in the second quarter of 2026.

TPST-2206: Autologous Dual-Targeting CD70/CD70 CAR-T

CD70 is a protein that is often expressed on the surface of cells that make up a solid tumor, including in patients with renal cell carcinoma (“RCC”). While therapeutic approaches targeting CD70 have shown promise across various experimental settings, some cancer cells within a solid tumor may only express low levels of CD70, while other cancer cells may downregulate expression of CD70 during treatment with a CD70-targeting therapy.

TPST-2206 is an autologous dual-targeting CD70/CD70 CAR-T product that we are developing for the treatment of RCC. TPST-2206 uses the same dual-targeting architecture as TPST-2003, but replaces the CD19 and BCMA-targeting CARs with two CD70-targeting CARs. We believe that this dual-targeting structure may allow TPST-2206 to more effectively target and treat CD70-expressing solid tumors than single-targeting approaches. TPST-2206 is being evaluated in pre-clinical studies with a Phase 1 clinical trial of TPST-2206 in patients with RCC planned to begin in the second quarter of 2026. These pre-clinical activities and the planned Phase 1 clinical trial are being conducted and sponsored by our strategic partner, Novatim. We are planning to review the results of these studies, and, depending on those data, evaluate the potential to develop TPST-2206 in countries other than China, India, Turkey, and Russia.

TPST-3206: Allogeneic Dual-Targeting CD70/CD70 CAR-T

TPST-3206 is an allogeneic dual-targeting CD70/CD70 CAR-T product that we are developing for the treatment of RCC. TPST-3206 uses the same dual-targeting structure as TPST-2206 and the same manufacturing approach as our other allogeneic CAR-T program, TPST-3003. We are planning to review the results of the ongoing pre-clinical and planned clinical evaluation of TPST-2206, which is being conducted and sponsored by Novatim, and, depending on those data, evaluate the potential to develop TPST-3206 in countries other than China, India, Turkey, and Russia.

Small Molecule Programs

Amezalpat: PPARα Transcription Factor Antagonist

Amezalpat, a potentially first-in-class oral small molecule antagonist of PPARα, has completed a Phase 1a/b trial, and a global randomized Phase 1b/2 trial. The Phase 1a/b trial was a multicenter, open-label, dose-escalation, that evaluated amezalpat as both a monotherapy and combination therapy with nivolumab in patients with advanced solid tumors. Results from both the monotherapy and combination arms were presented in an oral presentation at the ASCO conference in 2022. The Phase 1b/2 trial was a randomized, multicenter, global study in collaboration with Roche that was evaluating amezalpat in combination with atezolizumab (TECENTRIQ®) and bevacizumab (Avastin®) in previously untreated patients with advanced HCC, compared to atezolizumab and bevacizumab alone, which is a standard of care for that indication and patient population. As of an updated February 14, 2024 data cutoff date, the global randomized Phase 1b/2 trial continued to show positive outcomes in patients with advanced or metastatic HCC who received the amezalpat combination therapy as compared to the control arm, including a survival benefit in both the overall population and key subpopulations.

Tumors evolve to promote their own survival by alternating energy sources, promoting angiogenesis and evading immune recognition. PPARα is a transcription factor that is activated through binding of long-chain fatty acid ligands, which in turn regulates the expression of genes that control glucose and lipid homeostasis, inflammation, proliferation, differentiation and cell death. Included among these regulated genes are those that enable fatty acid oxidation (“FAO”), and β-oxidation metabolic pathways in cellular peroxisomes and in mitochondria. An FAO metabolic profile is associated with tumor proliferation, induction of angiogenesis and immune suppression. Published studies and internal Tempest analyses of over 9,000 primary or metastatic tumor samples in the Human Cancer Genome public database reveal a metabolic gene expression profile characterized by increased PPARα, FAO genes and lipogenesis associated with increased metastatic potential and reduced survival enrichment among multiple cancers, including HCC, CCA, breast carcinoma, colorectal adenocarcinoma, RCC, lung adenocarcinoma and prostate adenocarcinoma. Amezalpat is designed to block the pathways that support tumor cell proliferation, angiogenesis and immune suppression, resulting in reduced disease and patient benefit.

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Summary of Amezalpat Preclinical Results

We have conducted pre-clinical pharmacology studies along with pharmacokinetics (“PK”), and toxicology studies with amezalpat to support its ongoing evaluation for the treatment of patients with advanced solid tumors. The combined results of the preclinical studies that we have performed indicate that amezalpat has a dual anti-tumor mechanism of action that involves both directly inhibiting tumor proliferation and targeting suppressive immune response pathways to promote effective tumor-specific immunity. Our preclinical results support the large body of published literature that the PPARα target genes play an integral role in tumor growth, angiogenesis and evasion of immune recognition, and provide the scientific rationale for targeting this pathway with amezalpat.

Immune checkpoint blockade enhances anti-tumor immunity by restoring the activity of cytotoxic T (Teff) cells. Emerging experimental results suggest that inhibiting FAO with a PPARα antagonist may target resistance mechanisms to both anti-PD-L1/PD-1 and anti-VEGF therapies, supporting the combination of amezalpat with either or both therapies. We have conducted preclinical studies showing that while both amezalpat or anti-PD-1 monotherapy inhibited outgrowth of established flank MC38 tumors, the combination of these two agents resulted in synergistic anti-tumor activity. In addition, MC38 tumor-bearing mice cured by the combination therapy, unlike age-matched naïve control mice, were completely resistant to tumor growth when rechallenged with autologous MC38 tumor cells, demonstrating that amezalpat in combination with anti-PD-1 induced lasting tumor-specific immune memory. In addition, activating mutations in the Wnt/B-catenin pathway represent the most frequently dysregulated pathway in HCC. Such mutations render a tumor cell dependent upon FAO for its energy source, and in preclinical studies, Tempest has shown reduction and long-term durable cures in mice bearing Wnt/B-catenin activated HCC tumors treated with amezalpat and an immune checkpoint inhibitor. The promise of these pre-clinical results have been observed in the clinic, where we observed increased clinical benefit in our Phase 1b/2 study in HCC patients who had a mutation in this pathway.

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Efficacy in Syngeneic β-Catenin-driven Hepatocellular Carcinoma Model

Tumor resistance to anti-angiogenic drugs is also associated with elevated lipogenesis and FAO, primarily through the vascular regression and hypoxic environment that this class of therapies engenders. In response, tumor cells can switch to FAO as a mechanism of resistance against anti-angiogenic therapy. In a preclinical study, we confirmed that combination of amezalpat with tyrosine kinase inhibitor-(“TKI-”), based anti-angiogenesis therapy confers potent anti-tumor activity.

The preclinical data for amezalpat are consistent with the data observed from our Phase 1 trial presented at ASCO in 2022. Taken together, we believe the hypothesis behind the amezalpat program, the preclinical data, and the Phase 1 data support the design of, and data observed from, the ongoing study of amezalpat in first-line HCC in combination with standard of care as well as the potential evaluation of amezalpat in combination with other therapeutic agents, such as a tyrosine kinase inhibitor (“TKI”), in FAO-reliant malignancies such as HCC and RCC.

Overview of amezalpat Clinical Trials

We completed a Phase 1a/b study and a global randomized Phase 1b/2 clinical study of amezalpat. We have released positive data from both studies, and we believe the continued positive data announced in 2024 supports the advancement of amezalpat to a pivotal Phase 3 trial in first-line HCC. The Phase 1a/b trial evaluated both monotherapy and combination therapy with the anti-PD-1 agent nivolumab in patients with advanced solid tumors that our PPARα-dependent transcriptome analysis of diverse human cancers revealed favor the usage of FAO. Results from both the monotherapy and the combination arms were presented in an oral presentation at the ASCO conference in 2022.

Amezalpat demonstrated monotherapy clinical benefit in patients with late-line, treatment-refractory cancers where objective responses (RECIST v1.1) would not be expected, including pancreatic, CCA, and colorectal cancers (“CRC”). Results showed that 53% (10/19) of patients experienced clinical benefit in the form of disease control, including tumor shrinkage in 21% of the patients. One subject with late line CCA had a 15% tumor shrinkage and was on study for over nine months of treatment, while also demonstrating on-target inhibition of expression of PPARα target genes on pharmacodynamic (“PD”) assessment.

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In the combination therapy portion of the trial, 15 evaluable patients with heavily pretreated RCC, HCC and CCA were treated with oral twice-daily amezalpat and the anti-PD-1 therapy, nivolumab. All the HCC and RCC patients had received an approved anti-PD-1 therapy in at least one prior line of therapy and discontinued that treatment due to disease progression. We observed objective responses (RECIST v1.1) in two patients with late-line RCC who had previously progressed on anti-PD-1 therapy without having achieved an objective response (ORR 50%, n=2/4, in evaluable RCC patients), and we observed mixed response in a third RCC IO-refractory patient with significant reduction (>30%) in the target lesion, but the appearance of new disease precluded designation as a RECIST PR. A third RECIST response was observed in a patient with late-line, heavily pre-treated CCA, a tumor type generally not responsive to anti-PD-1 therapy alone. All the RECIST responses were observed at the two highest doses.

Notably, one RCC patient who achieved a response after treatment with amezalpat and nivolumab had previously been treated with nivolumab in combination with ipilimumab without experiencing an objective response and progressed on treatment, followed by further progression of cancer on both cabozantinib and everolimus. The initial RECIST PR was seen at the first on-study assessment at eight weeks and included a response in all target lesions as well as complete radiographic resolution of multiple sites of metastatic disease (see CT scan below) and has been confirmed at subsequent assessments beyond 12 months.

Partial Response in Late-Line RCC Patient Treated with amezalpat

and Nivolumab Combination Therapy

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Randomized Data in HCC

As of an updated February 14, 2024 data cutoff date, the global randomized Phase 1b/2 trial of amezalpat, combined with the standard-of-care first-line regimen of atezolizumab and bevacizumab continued to show positive results in patients with advanced or metastatic HCC. The study is comparing the amezalpat arm to standard of care alone, and enrolled 40 patients randomized to the amezalpat arm and 30 patients randomized to the control arm. With 10 additional months of follow-up since the April 2023 primary analysis, the median OS in the amezalpat arm reached 21 months, representing a 6-month improvement over the 15-month OS in the control arm. Importantly, the HR remained stable, demonstrating a sustained reduction in the relative risk of death compared to the control arm.

At the data cutoff date, 50% (20/40) of patients in the amezalpat arm remained in survival follow-up versus 30% (9/30) in the control arm. We believe this reinforces the meaningful clinical benefit observed in this population, with OS serving as the primary endpoint for regulatory approval globally for first-line HCC.

The confirmed ORR for the amezalpat arm remained consistent at 30%, compared to 13.3% in the control arm. Notably, one patient in the amezalpat arm who had previously achieved a PR as of April 2023 converted to a CR by February 2024, with at least an 80% reduction in tumor burden. This patient, despite having a PD-L1 score <1% and an immune desert phenotype, achieved a CR with the addition of amezalpat, highlighting its potential efficacy in hard-to-treat tumors.

1. Data not provided by Roche

Additionally in biomarker subpopulation analyses, patients with b-catenin activating mutations (21% of the study population) showed an increased confirmed ORR of 43% and a DCR of 100% in the amezalpat arm. The triplet regimen with amezalpat remained active across PD-L1 negative tumors, with a confirmed ORR of 27% in the amezalpat arm, compared to a reduced ORR of 7% for the control arm.

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Early in the development of amezalpat, given the expression profile and attributes of PPARα, we selected HCC, RCC and CCA as cancers of interest and checkpoint inhibitors and anti-angiogenic therapeutics as potential companion therapies with the goal to maximize the opportunity to bring meaningful benefit to patients with these cancers. Based on the pre-clinical and clinical data released to date, we believe that the emerging clinical benefit profile of amezalpat for patients shows alignment with these predictions, and we look forward to the potential benefit amezalpat could bring to patients with these cancers.

We own worldwide rights to amezalpat, and have filed and been issued patents, including composition of matter, pharmaceutical compositions, and related methods of use, which are expected to expire between December 2033 and November 2043, without giving effect to any patent term extensions.

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TPST-1495: Dual EP2/EP4 Prostaglandin Receptor Antagonist

Our second small-molecule product candidate is TPST-1495, a potentially first-in-class, oral, small molecule dual antagonist of the prostaglandin E2 (“PGE2”), receptors, EP2 and EP4. TPST-1495 is engineered to inhibit only these receptors while sparing the homologous - but differentially active - EP1 and EP3 receptors.

There is extensive literature demonstrating that PGE2 both enhances tumor proliferation and inhibits anti-cancer immune function; it is known from the scientific literature that many tumors express elevated levels of the cyclooxygenase enzymes that produce PGE2. Elevated expression of COX-2 and overproduction of PGE2 is correlated with progression of diverse malignancies by stimulating tumor cell proliferation, survival, evasion and metastasis as well as host angiogenesis. In addition, PGE2 suppresses anti-tumor immunity by inhibiting the function of critical anti-tumor immune effector cell populations such as dendritic cells, natural killer (“NK cells”), T cells, and M1 macrophages, while promoting the activity of suppressive immune cell populations including myeloid-derived suppressor cells (“MDSCs”), M2 macrophages, and regulatory T cells. Recent studies have also shown that increased expression of COX-2 and production of PGE2 can play a role in the effectiveness of immune checkpoint inhibitor therapy and in the development of adaptive resistance to therapy. This body of literature provides the scientific rationale for developing therapeutics that maximally inhibit the prostaglandin pathway, as well as for combining TPST-1495 with immune checkpoint inhibitor monoclonal antibodies.

We conducted preclinical studies to evaluate TPST-1495, including its ability to reverse PGE2-mediated suppression of primary human monocyte to dendritic cell differentiation and activation in vitro, as well as comparisons to other agents designed to operate in the same pathway such as a single EP4 antagonist and, as described, COX2.

We have also conducted preclinical studies to evaluate TPST-1495 in a spontaneous APCMin/+ mouse model of FAP that demonstrated a significant survival advantage in comparison to other inhibitors in the prostaglandin pathway.

Source: Francica et al., Cancer Res Commun; 3(8) August 2023 https://doi.org/10.1158/2767-9764.CRC-23-0249

Overview of Ongoing TPST-1495 Clinical Trials

TPST-1495 was evaluated in a first-in-human, Phase 1, multicenter, open-label, schedule and dose optimization trial in subjects with late-stage solid tumor cancers that are deemed incurable. Study objectives include evaluation of safety, tolerability, PK, PD, and preliminary anti-tumor activity of TPST-1495 as monotherapy and in combination with the checkpoint inhibitor,

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pembrolizumab. TPST-1495 has been evaluated on a once daily (“QD”) or twice daily (“BID”) schedule and with continuous or intermittent administration as monotherapy and in combination with pembrolizumab. Results from the Phase 1 study were presented at ASCO 2023. The data showed that in a diverse and treatment-refractory patient population, treatment with TPST-1495 as a monotherapy and in combination with pembrolizumab resulted in tumor shrinkage and prolonged stable disease in certain patients with a monotherapy safety profile on the recommended QD schedule that was tolerable, with predominantly Grade 1-2 treatment related adverse events (“TRAEs”). For the combination with pembrolizumab, Grade 1-3 TRAEs were reported.

Our preclinical results in the APCMin/+ lead us to consider the application of TPST-1495 in familial adenomatous polyposis syndrome (“FAP”). FAP is a hereditary condition characterized by the development of numerous polyps in the colon and rectum. These polyps have the potential to become cancerous if left untreated. FAP is caused by mutations in the APC gene, which normally helps regulate cell growth and division in the intestinal lining. Individuals with FAP have a significantly increased risk of developing colorectal cancer at a young age, often before the age of 40. Additionally, FAP can lead to the development of polyps in other parts of the gastrointestinal tract, as well as other non-gastrointestinal tumors. Management of FAP typically involves regular surveillance with colonoscopies and surgical intervention to remove the polyps and reduce the risk of cancer. Currently, there are no systemic therapies approved to treat FAP. We are working with CP-CTNet on an NCI-funded Phase 2 study, which we expect will begin this year.

As of December 31, 2025, we own worldwide rights to TPST-1495, and our issued United States patents covering TPST-1495 as compositions of matter, pharmaceutical compositions and related methods of use, are expected to expire between April 2038 and April 2039, without giving effect to any patent term adjustments or patent term extensions for regulatory delay.

License and Collaboration Agreements

Novatim License and Collaboration Agreement

On July 18, 2025, Erigen entered into an Exclusive License and Collaboration Agreement (the “Novatim License Agreement”) with Novatim. On February 3, 2026, the Novatim License Agreement was assigned to us in connection with the Closing pursuant to the Asset Purchase Agreement.

Pursuant to the Novatim License Agreement, we obtained an exclusive license to specified patents and know-how in all fields worldwide, but excluding Greater China, India, Turkey, and Russia, to exploit the TPST-2003 and TPST-2206 programs and allogeneic CAR-T therapies based on the TPST-2003 and TPST-2206 programs. We also received a right of first negotiation to negotiate a license to exploit allogeneic CAR-T therapies and in vivo CAR-T therapies in Greater China. We are obligated to meet certain diligence milestones by specified dates and to use commercially reasonable efforts to develop and make commercially available at least one licensed product in the licensed territory. No upfront payment was paid pursuant to the Novatim License Agreement. We are obligated to pay Novatim up to $80 million in total upon achievement of certain development milestones for the programs and up to $1.24 billion in total upon achievement of certain commercial milestones for the programs. In addition, we are required to pay Novatim mid-to-high single digit royalties on net sales of licensed products, subject to certain customary reductions, up to a lifetime maximum of $800 million, following which our license shall become fully paid and royalty-free.

The Novatim License Agreement is subject to termination (i) by either party, subject to specified cure periods, for the material breach by the other party or the bankruptcy or insolvency of the other party, or (ii) by mutual agreement of the parties.

Factor Amended and Restated License and Collaboration Agreement

On November 19, 2025, Erigen entered into an Amended and Restated License and Collaboration Agreement (the “Restated Factor License Agreement”) with Factor Bioscience Limited. On February 3, 2026, the Restated Factor License Agreement was assigned to us in connection with the Closing pursuant to the Asset Purchase Agreement.

Pursuant to the Restated Factor License Agreement, we obtained an exclusive license to specified patents in all fields worldwide, but excluding Greater China, India, Turkey, and Russia (the “Licensed Territory”), to exploit the TPST-3003 and TPST-3206

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programs. The Restated Factor License Agreement also established a Joint Steering Committee for the purposes of discussing and coordinating collaboration opportunities and serving as a forum for information sharing. We are obligated to meet certain diligence milestones by specified dates and to use commercially reasonable efforts to develop and make commercially available at least one licensed product in the licensed territory. No upfront payment was paid pursuant to the Restated Factor License Agreement. We are obligated to pay Factor Bioscience Limited up to $40 million in total upon achievement of certain development milestones for the programs and up to $620 million in total upon achievement of certain commercial milestones for the programs. In addition, we are required to pay Factor Bioscience Limited mid-single digit to high-teens royalties on net sales of licensed products on a country-by-country and licensed product-by-licensed product basis until expiration of the last to expire valid claim of certain licensed patents covering such licensed product in such country, subject to certain customary reductions, and low-to-mid double digit sublicense fees.

The Restated Factor License Agreement will continue until expiration of the last-to-expire Royalty Term. “Royalty Term” is defined as, on a product-by-product and country-by-country basis, the period commencing on the first arms-length sale of a product in a country of the Licensed Territory, and ending on the date of expiration of the last to expire valid patent covering the exploitation of the applicable product in the applicable country of the Licensed Territory. The Restated Factor License Agreement is subject to termination (i) by either party, subject to specified cure periods, for the material breach by the other party or the bankruptcy or insolvency of the other party, (iii) by us for any reason upon 60 days notice, or (iii) by mutual agreement of the parties.

Factor Amended and Restated Master Services Agreement

On November 19, 2025, Erigen entered into an Amended and Restated Master Services Agreement (the “Restated Factor Services Agreement”) with Factor. On February 3, 2026, the Restated Factor Services Agreement was assigned to us in connection with the Closing pursuant to the Asset Purchase Agreement.

Pursuant to the Restated Factor Services Agreement, Factor will perform services requested by us on a fee-for-services basis and provide us access to Factor’s facilities as mutually agreed upon in one or more written work orders. All deliverables developed as a result of Factor’s performance of the services or as set forth in a work order, other than specified improvements, will be our property and confidential information. Furthermore, Factor granted us a freedom-to-operate license to its background intellectual property, excluding certain technology and improvements licensed under the Restated Factor License Agreement, solely to the extent necessary or reasonably useful to use, practice or otherwise exploit the deliverables.

Either party may terminate the Restated Factor Services Agreement at any time without cause upon 30 days’ notice, provided that termination of the Restated Factor Services Agreement will not terminate any ongoing work orders. Either party may terminate individual work orders in accordance with the terms of the applicable work order.

Roche Collaboration Agreement

In February 2021, we entered into a collaboration agreement with F. Hoffmann-La Roche Ltd. (“Roche”) to accelerate the development of amezalpat into a global, first-line, randomized study. The companies are evaluating amezalpat in a Phase 1b/2 clinical study in combination with the standard-of-care first-line regimen of atezolizumab and bevacizumab in patients with advanced or metastatic HCC, not previously treated with systemic therapy. Pursuant to the terms of the agreement, Roche is managing the study operations for the trial, and we retain global development and commercialization rights to amezalpat. Pursuant to the agreement, Roche provides us with notice of the amount of amezalpat required and the delivery timeline, and we supply the amezalpat. All rights to invention and discoveries relating solely to amezalpat or biomarkers solely related to amezalpat made during any study will be our exclusive property. All data generated in the performance of any study under the collaboration agreement will be the property of Roche, but we are entitled to use the data for any lawful purpose.

The agreement applies on a study-by-study basis until the last treatment of the last patient in a study receiving amezalpat in accordance with the protocol for such study or until the termination of this collaboration agreement by either party. Each party has the right to terminate the collaboration agreement upon 60 days prior written notice to the other party. Upon any termination

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of the agreement, neither we nor Roche will be entitled to any compensation, damages or other payment. If any individual study supplement is terminated, Roche must return all unused amezalpat to us free of charge or destroy such product at our request.

Roche Master Clinical Supply Agreement

In October 2024, we entered into a master clinical supply agreement (“Roche Supply Agreement”) with Roche, pursuant to which Roche will supply Roche’s atezolizumab (TECENTRIQ) for use in one or more clinical studies conducted by us involving amezalpat in combination with atezolizumab, in each case, in accordance with the applicable study protocol prepared by us and reviewed by Roche. Under the Roche Supply Agreement, the parties may execute one or more clinical supply agreement supplements (each, a “CSA Supplement”) that will set forth the study to be conducted by us, the quantities of atezolizumab to be supplied by Roche for such study, and the delivery timeline for such quantities of atezolizumab. In October 2024, we entered into a CSA Supplement for Roche to supply atezolizumab to us, free of charge, for use in a potential Phase 3 trial.

Sales and Marketing

We intend to retain significant development and commercial rights to our product candidates and, if marketing approval is obtained, to commercialize our product candidates with a partner, in the United States and other regions. We currently have no sales, marketing or commercial product distribution capabilities. Clinical data, the size of the addressable patient population, the size of the commercial infrastructure and manufacturing needs may all influence or alter our commercialization plans.

Manufacturing

We do not own or operate, and currently have no plans to establish, any manufacturing facilities. We rely and expect to continue to rely on third parties for the manufacture of our product candidates for preclinical and clinical testing, as well as for commercial manufacture if any of our product candidates obtain marketing approval. We also rely, and expect to continue to rely, on third parties to package, label, store and distribute our investigational product candidates, as well as for our commercial products if marketing approval is obtained. We have internal personnel and utilize consultants with extensive technical, manufacturing, analytical and quality experience to oversee contract manufacturing and testing activities. We will continue to expand and strengthen our network of third-party providers but may also consider investing in internal manufacturing capabilities in the future if there is a technical need, or a strategic or financial benefit.

Manufacturing is subject to extensive regulations that impose procedural and documentation requirements. At a minimum these regulations govern record keeping, manufacturing processes and controls, personnel, quality control and quality assurance. Our systems, procedures and contractors are required to comply with these regulations and are assessed through regular monitoring and formal audits.

Competition

The biopharmaceutical and immuno-oncology industries are characterized by intense competition and rapid innovation. Any product candidates that we successfully develop and commercialize will have to compete with existing and future new therapies. While we believe that our technology, development experience and scientific knowledge provide us with competitive advantages, we face potential competition from many different sources, including large and specialty pharmaceutical and biotechnology companies, academic research institutions, government agencies and public and private research institutions that conduct research, seek patent protection, and establish collaborative arrangements for research, development, manufacturing and commercialization.

If our current or any future product candidates are approved for the treatment of cancer, they may compete with existing therapies as well as product candidates currently in development. There are a variety of treatments used for cancerous tumors that include chemotherapy drugs, small molecules, monoclonal antibodies, antibody-drug conjugates, bi-specific antibodies, cell therapies, oncolytic viruses and vaccines, as well as other approaches. In addition, there are several competitors in clinical development for

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the treatment of HCC, RCC, cholangiocarcinoma, and other indications that we may target with TPST-1495, and amezalpat, including companies such as Ono, Adlai Nortye, Merck, Roche, Exelixis, and AstraZeneca.

In the field of cell therapies, there are several competitors developing CAR-T and other cellular therapies for the treatment of system lupus erythematosus (SLE), multiple myeloma, and other hematologic malignancies that we may target with TPST-2003, TPST-3003 and TPST-4003, including companies such as Johnson & Johnson, Bristol Meyers Squibb, Gilead Sciences, Arcellx, Legend Biotech, Allogene, Cellectis, AstraZeneca and other biotechnology and pharmaceutical companies developing BCMA-targeting and dual-targeting cell therapies.

TPST-2003, our dual-targeting CD19/BCMA CAR-T cell therapy is, to our knowledge, the first parallel structure CD19/BCMA dual-targeting CAR-T under development for the treatment of rrMM specifically targeting patients with EMD. We are aware of other clinical-stage CD19/BCMA dual-targeting CAR-T product candidates, including a product under development by AstraZeneca. We are also aware of several approved therapies and products under development that utilize either a CD19 or BCMA single-targeting CAR structure. Amezalpat, our small molecule designed to be a selective antagonist of PPARα, is, to our knowledge, the first PPARα antagonist to enter the clinic. We are not aware of other companies developing such an antagonist. For TPST-1495, our small molecule designed to be a dual antagonist of the EP2 and EP4 receptor, we are aware of other clinical-stage EP-4-only antagonists being developed by Adlai Nortye and Ono.

Many of our competitors, either alone or with strategic partners, have substantially greater financial, technical and human resources than we do. Accordingly, our competitors may be more successful than us in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining approval for treatments and achieving widespread market acceptance, rendering our treatments obsolete or non-competitive. Merger and acquisition activity in the biotechnology and biopharmaceutical industries may result in even more resources being concentrated among a smaller number of our competitors. These companies also compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites and patient registration for clinical trials and acquiring technologies complementary to, or necessary for, our programs. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies.

Our commercial opportunity could be substantially limited if our competitors develop and commercialize products that are more effective, safer, less toxic, more convenient or less expensive than our comparable products. In geographies that are critical to our commercial success, competitors may also obtain regulatory approvals before us, resulting in our competitors building a strong market position in advance of the entry of our products. The key competitive factors affecting the success of all our programs are likely to be their efficacy, safety, convenience and availability of reimbursement. In addition, our ability to compete may be affected in many cases by insurers or other third-party payors seeking to encourage the use of generic drugs.

Intellectual Property

We strive to protect and enhance the proprietary technology, inventions and improvements that are commercially important to our business, including obtaining, maintaining, and defending our patent rights. Our policy is to seek to protect our proprietary position by, among other methods, filing patent applications and obtaining issued patents in the United States and in markets outside of the United States directed to our proprietary technology, inventions, improvements, and product candidates that are important to the development and implementation of our business. We also rely on trade secrets and know-how relating to our proprietary technology and product candidates and continuing innovation to develop, strengthen and maintain our proprietary position in the field of oncology. We also plan to rely on data exclusivity, market exclusivity and patent term extensions when available. Our commercial success will depend in part on our ability to obtain and maintain patent and other proprietary protection for our technology, inventions, improvements, and product candidates; to preserve the confidentiality of our trade secrets; to defend and enforce our proprietary rights, including any patents that we may own or license in the future; and to operate without infringing on the valid and enforceable patents and other proprietary rights of third parties.

With respect to TPST-2003, as of February 28, 2026, our in-licensed patent portfolio included one pending U.S. patent application, and nine pending patent applications in various markets outside of the United States, including Europe and Japan.

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The pending patent applications cover TPST-2003 as compositions of matter, pharmaceutical compositions, and related methods of use. Any patents that may issue from the pending patent applications are expected to expire in March 2044, absent any patent term adjustments or patent term extensions for regulatory delay.

With respect to TPST-2206, as of February 28, 2026, our in-licensed patent portfolio included two pending PCT applications. The pending PCT applications cover TPST-2206 as compositions of matter, pharmaceutical compositions and related methods of use. Any patents that may issue from the pending PCT applications are expected to expire in July 2045, absent any patent term adjustments or patent term extensions for regulatory delay.

With respect to our TPST-3003, TPST-3206, and TPST-4003 programs, as of February 28, 2026, our in-licensed patent portfolio included ten issued U.S. patents, four pending U.S. patent applications, one pending PCT application, and five issued patents and eight pending patent applications in various markets outside of the United States, including Europe and Japan. The issued U.S. patents are expected to expire in May 2032, absent any patent term adjustments or patent term extensions for regulatory delay. Any additional patents that may issue from these pending patent applications are expected to expire between May 2032 and April 2045, absent any patent term adjustments or patent term extensions for regulatory delay.

As of December 31, 2025, our patent portfolio consisted of issued patents and pending patent applications that we own related to amezalpat and TPST-1495. In total, as of the same date, we owned ten issued United States patents, four pending United States patent applications, one pending Patent Cooperation Treaty (“PCT”) application, and in various markets outside of the United States, including Europe, China and Japan: 68 issued patents and 8 pending patent applications.

With respect to amezalpat, as of December 31, 2025, we owned issued patents and pending patent applications in the United States, Europe, China, Japan, and other markets outside of the United States as well as one pending PCT application. The issued United States patents covering amezalpat as compositions of matter, pharmaceutical compositions, and related methods of use are expected to expire in December 2033, absent any patent term adjustments or patent term extensions for regulatory delay. Any additional patents that may issue from these pending patent applications are expected to expire between December 2033 and March 2046, absent any patent term adjustments or patent term extensions for regulatory delay.

With respect to TPST-1495, as of December 31, 2025, we owned issued patents and pending patent applications in the United States, Europe, China, Japan, and other markets outside of the United States. The issued United State patents covering TPST-1495 as compositions of matter, pharmaceutical compositions, and related methods of use are expected to expire between April 2038 and April 2039, absent any patent term adjustments or patent term extensions for regulatory delay. Any additional patents that may issue from these pending patent applications are expected to expire between April 2038 and April 2039, absent any patent term adjustments or patent term extensions for regulatory delay.

We also possess substantial know-how and trade secrets relating to the development and commercialization of our product candidates, including related manufacturing processes and technology.

With respect to our product candidates and processes that we intend to develop and commercialize in the normal course of business, we intend to pursue patent protection covering, when possible, compositions, methods of use, dosing, and formulations. We may also pursue patent protection with respect to manufacturing and drug development processes and technologies.

Issued patents can provide protection for varying periods of time, depending upon the date of filing of the patent application, the date of patent issuance and the legal term of patents in the countries in which they are obtained. In general, patents issued for patent applications filed in the United States can provide exclusionary rights for 20 years from the earliest effective filing date. The term of United States patents may be extended by delays encountered during prosecution that are caused by the USPTO, also known as patent term adjustment. In addition, in certain instances, the term of an issued United States patent that covers or claims an FDA approved product can be extended to recapture a portion of the term effectively lost as a result of the FDA regulatory review period, which is called patent term extension. The restoration period cannot be longer than five years and the total patent term, including the restoration period, must not exceed 14 years following FDA approval. The term of patents outside of the

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United States varies in accordance with the laws of the foreign jurisdiction but typically is also 20 years from the earliest effective filing date. However, the actual protection afforded by a patent varies on a product-by-product basis, from country-to-country and depends upon many factors, including the type of patent, the scope of its coverage, the availability of regulatory-related extensions, the availability of legal remedies in a particular country and the validity and enforceability of the patent.

The patent positions of companies like ours are generally uncertain and involve complex legal and factual questions. No consistent policy regarding the scope of claims allowable in patents in the field of oncology has emerged in the United States. The relevant patent laws and their interpretation outside of the United States are also uncertain. Changes in either the patent laws or their interpretation in the United States and other countries may diminish our ability to protect our technology or product candidates and could affect the value of such intellectual property. In particular, our ability to stop third parties from making, using, selling, offering to sell, or importing products that infringe our intellectual property will depend in part on our success in obtaining and enforcing patent claims that cover our technology, inventions, and improvements. We cannot guarantee that patents will be granted with respect to any of its pending patent applications or with respect to any patent applications we may file in the future, nor can we be sure that any patents that may be granted to us in the future will be commercially useful in protecting its products, the methods of use or manufacture of those products.

Moreover, even its issued patents may not guarantee us the right to practice our technology in relation to the commercialization of its products. Patent and other intellectual property rights in the pharmaceutical and biotechnology space are evolving and involve many risks and uncertainties. For example, third parties may have blocking patents that could be used to prevent us from commercializing our product candidates and practicing our proprietary technology, and our issued patents may be challenged, invalidated, or circumvented, which could limit our ability to stop competitors from marketing related products or could limit the term of patent protection that otherwise may exist for its product candidates. In addition, the scope of the rights granted under any issued patents may not provide us with protection or competitive advantages against competitors with similar technology. Furthermore, our competitors may independently develop similar technologies that are outside the scope of the rights granted under any issued patents. For these reasons, we may face competition with respect to our product candidates. Moreover, because of the extensive time required for development, testing, and regulatory review of a potential product, it is possible that, before any particular product candidate can be commercialized, any patent protection for such product may expire or remain in force for only a short period following commercialization, thereby reducing the commercial advantage the patent provides.

Government Regulation

Government authorities in the United States at the federal, state and local level and in other countries and jurisdictions extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, labeling, packaging, storage, record-keeping, promotion, advertising, distribution, post-approval monitoring and reporting, marketing and export and import of pharmaceutical products, such as our investigational medicines and any future investigational medicines. Generally, before a new pharmaceutical product can be marketed, considerable data demonstrating its quality, safety and efficacy must be obtained, organized into a format specific for each regulatory authority, submitted for review and approved by the regulatory authority.

FDA Approval Process

In the United States, biopharmaceutical products are subject to extensive regulation by the FDA under the Federal Food, Drug, and Cosmetic Act (“FFDCA”), the Public Health Service Act, and other federal and state statutes and regulations govern, among other things, the research, development, testing, manufacture, storage, recordkeeping, approval, labeling, promotion and marketing, distribution, post-approval monitoring and reporting, sampling and import and export of biopharmaceutical products. Failure to comply with applicable U.S. requirements may subject a company to a variety of administrative or judicial sanctions, such as clinical hold, FDA refusal to approve pending New Drug Applications (“NDAs”) or Biologic License Applications (“BLAs”), warning or untitled letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, civil penalties and criminal prosecution.

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Our investigational medicines and any future investigational medicines must be approved by the FDA before they may be legally marketed in the United States. The process generally involves the following:

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Completion of extensive preclinical laboratory and animal studies in accordance with applicable regulations, including studies conducted in accordance with Good Laboratory Practice (“GLP”) requirements;

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Submission to the FDA of an IND, which must become effective before human clinical trials may begin;

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Approval by an Institutional Review Board (“IRB”) or independent ethics committee at each clinical trial site before each clinical trial may be commenced;

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Performance of adequate and well-controlled human clinical trials in accordance with applicable Investigational New Drug (“IND”) regulations, Good Clinical Practice (“GCP”) requirements and other clinical trial-related regulations to establish the safety and efficacy of the investigational product for each proposed indication;

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Submission to the FDA of an NDA for small molecule candidates and BLA for biologic candidates;

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Payment of any user fees for FDA review of applications;

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A determination by the FDA within 60 days of its receipt of an application to accept the filing for review;

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Satisfactory completion of one or more FDA pre-approval inspections of the manufacturing facility or facilities where the drug, or components thereof, will be produced to assess compliance with Good Manufacturing Practices (“cGMP”) requirements to assure that the facilities, methods and controls are adequate to preserve the product’s identity, strength, quality and purity, and in the case of cell therapies, compliance with Good Tissue Practices;

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Satisfactory completion of any potential FDA audits of the clinical trial sites that generated the data in support of the application to assure compliance with GCPs and integrity of the clinical data;

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FDA review and approval of an NDA or BLA, including consideration of the views of any FDA advisory committee; and

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Compliance with any post-approval requirements, including risk evaluation and mitigation strategy (“REMS”), where applicable, and post-approval studies required by the FDA as a condition of approval.

The preclinical and clinical testing and approval process requires substantial time, effort and financial resources, and we cannot be certain that any approvals for our product candidates will be granted on a timely basis, or at all.

Preclinical Studies

Before testing any product candidates in humans, the product candidate must undergo rigorous preclinical testing. Preclinical tests include laboratory evaluation of product chemistry, formulation and toxicity, as well as in vitro and animal studies to assess the potential for adverse events and in some cases to establish a rationale for therapeutic use. The conduct of the preclinical tests must comply with federal regulations and requirements, including GLP. An IND sponsor must submit the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical studies, among other things, to the FDA as part of an IND. An IND is a request for authorization from the FDA to administer an investigational product to humans and must become effective before human clinical trials may begin. Some long-term preclinical testing may continue after an IND is submitted. An IND automatically becomes effective 30 days after receipt by the FDA, unless before that time the FDA raises concerns or questions related to one or more proposed clinical trials and places the trial on clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. As a result, submission of an IND may not result in the FDA allowing clinical trials to commence.

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Clinical Trials

Clinical trials involve the administration of the investigational new drug or biologic to healthy volunteers or patients under the supervision of a qualified investigator, generally a physician not employed by or under the trial sponsor’s control. Clinical trials must be conducted: (i) in compliance with federal regulations; (ii) in compliance with GCP, an international standard meant to protect the rights and health of patients and to define the roles of clinical trial sponsors, administrators and monitors; as well as (iii) under protocols detailing, among other things, the objectives of the trial, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated in the trial. Each protocol involving testing on U.S. patients and subsequent protocol amendments must be submitted to the FDA as part of an IND.

Furthermore, each clinical trial must be reviewed and approved by an IRB for each institution at which the clinical trial will be conducted to ensure that the risks to individuals participating in the clinical trials are minimized and are reasonable in relation to anticipated benefits. The IRB also approves the informed consent form that must be provided to each clinical trial subject or his or her legal representative and must monitor the clinical trial until completed.

There also are requirements governing the reporting of ongoing clinical trials and completed clinical trial results to public registries. Information about certain clinical trials, including clinical trial results, must be submitted within specific timeframes for publication on the www.clinicaltrials.gov website. Information related to the product, patient population, phase of investigation, clinical trial sites and investigators and other aspects of the clinical trial is then made public as part of the registration. Disclosure of the results of these clinical trials can be delayed in certain circumstances for up to two years after the date of completion of the trial.

A sponsor who wishes to conduct a clinical trial outside of the United States may, but need not, obtain FDA authorization to conduct the clinical trial under an IND. If a foreign clinical trial is not conducted under an IND, the sponsor may submit data from the clinical trial to the FDA in support of an NDA. The FDA will accept a well-designed and well-conducted foreign clinical trial not conducted under an IND if the clinical trial was conducted in accordance with GCP requirements, and the FDA is able to validate the data through an onsite inspection if deemed necessary.

Clinical trials are generally conducted in three sequential phases, known as Phase 1, Phase 2 and Phase 3:

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Phase 1 clinical trials generally involve a small number of healthy volunteers or disease-affected patients who are initially exposed to a single dose and then multiple doses of the product candidate. The primary purpose of these clinical trials is to assess the metabolism, pharmacokinetics, pharmacologic action, side effect tolerability, safety of the product candidate, and, if possible, early evidence of effectiveness.

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Phase 2 clinical trials generally involve studies in disease-affected patients to evaluate proof of concept and/or determine the dosing regimen(s) for subsequent investigations. At the same time, safety and further pharmacokinetic and pharmacodynamic information is collected, possible adverse effects and safety risks are identified, and a preliminary evaluation of efficacy is conducted.

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Phase 3 clinical trials generally involve a large number of patients at multiple sites and are designed to provide the data necessary to demonstrate the effectiveness of the product for its intended use, its safety in use and to establish the overall benefit/risk relationship of the product and provide an adequate basis for product labeling. In most cases, the FDA requires two adequate and well-controlled Phase 3 clinical trials to demonstrate the efficacy of the drug.

These Phases may overlap or be combined. For example, a Phase 1/2 clinical trial may contain both a dose-escalation stage and a dose expansion stage, the latter of which may confirm tolerability at the recommended dose for expansion in future clinical trials (as in traditional Phase 1 clinical trials) and provide insight into the anti-tumor effects of the investigational therapy in selected subpopulation(s).

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Typically, during the development of oncology therapies, all subjects enrolled in Phase 1 clinical trials are disease-affected patients and, as a result, considerably more information on clinical activity may be collected during such trials than during Phase 1 clinical trials for non-oncology therapies. A single Phase 3 or Phase 2 trial with other confirmatory evidence may be sufficient in rare instances to provide substantial evidence of effectiveness (generally subject to the requirement of additional post-approval studies). The manufacturer of an investigational drug in a phase 2 or 3 clinical trial for a serious or life-threatening disease is required to make available, such as by posting on its website, its policy on evaluating and responding to requests for expanded access.

Phase 1, Phase 2, Phase 3 and other types of clinical trials may not be completed successfully within any specified period, if at all. The FDA, the IRB, or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including non-compliance with regulatory requirements or a finding that the patients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug has been associated with unexpected serious harm to patients. Additionally, some clinical trials are overseen by an independent group of qualified experts organized by the clinical trial sponsor, known as a data safety monitoring board or committee. This group provides authorization for whether a trial may move forward at designated checkpoints based on access to certain data from the trial.

Concurrent with clinical trials, companies usually complete additional animal studies and must develop additional information about the chemistry and physical characteristics of the product as well as finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the product and, among other things, companies must develop methods for testing the identity, strength, quality, potency and purity of the final product. Additionally, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the investigational medicines do not undergo unacceptable deterioration over their shelf life.

FDA Review Process

After completion of the required clinical testing, an NDA or BLA is prepared and submitted to the FDA. FDA approval of an NDA or BLA is required before marketing of the product may begin in the U.S. An NDA or BLA must include the results of all preclinical, clinical and other testing and a compilation of data relating to the product’s pharmacology, chemistry, manufacture and controls. To support marketing approval, the data submitted must be sufficient in quality and quantity to establish the safety and efficacy of the investigational product to the satisfaction of the FDA. FDA approval of an NDA or BLA must be obtained before a drug or biologic may be marketed in the United States. Under the Prescription Drug User Fee Act (“PDUFA”), each NDA or BLA must be accompanied by a substantial user fee. The FDA adjusts the user fees on an annual basis. Fee waivers or reductions are available in certain circumstances, including a waiver of the application fee for the first application filed by a small business. Additionally, no user fees are assessed on applications for products designated as orphan drugs, unless the product also includes a non-orphan indication. The sponsor under an approved application is also subject to an annual program fee.

The FDA reviews each submitted NDA or BLA before it determines whether to file it and may request additional information. The FDA must make a decision on whether to file an application within 60 days of receipt, and such decision could include a refusal to file by the FDA. Once the submission is filed, the FDA begins an in-depth review of the application. The FDA has agreed to certain performance goals in the review process. Most applications for standard review products are reviewed within ten months of filing; most applications for priority review are reviewed in six months from filing. Priority review can be applied to products that the FDA determines may offer significant improvement in safety or effectiveness compared to marketed products or where no adequate therapy exists. The review process for both standard and priority review may be extended by the FDA for three additional months to consider certain late-submitted information, or information intended to clarify information already provided in the submission. The FDA does not always meet its goal dates for standard and priority timeframes, and the review process can be extended by FDA requests for additional information or clarification.

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The FDA may also refer applications for novel products, or products that present difficult questions of safety or efficacy, to an outside advisory committee—typically a panel that includes clinicians and other experts—for review, evaluation and a recommendation as to whether the application should be approved and under what conditions, if any. The FDA is not bound by the recommendation of an advisory committee, but it generally follows such recommendations.

Before approving an NDA or BLA, the FDA will conduct a pre-approval inspection of the manufacturing facilities for the new product to determine whether they comply with cGMP requirements. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. The FDA also typically inspects clinical trial sites to ensure compliance with GCP requirements and the integrity of the data supporting safety and efficacy.

After the FDA evaluates the application and the manufacturing facilities, it issues either an approval letter or a complete response letter. A complete response letter (“CRL”), generally outlines the deficiencies in the submission and may require substantial additional testing, or information, in order for the FDA to reconsider the application, such as additional clinical data, additional pivotal clinical trial(s), and/or other significant and time-consuming requirements related to clinical trials, preclinical studies or manufacturing. If a CRL is issued, the applicant may resubmit the NDA or BLA addressing all of the deficiencies identified in the letter, withdraw the application, engage in formal dispute resolution or request an opportunity for a hearing. The FDA has committed to reviewing resubmissions in two or six months depending on the type of information included. Even if such data and information are submitted, the FDA may decide that an application does not satisfy the criteria for approval.

As a potential condition of approval, the FDA may require a REMS to help ensure that the benefits of the product outweigh the potential risks to patients. A REMS can include medication guides, communication plans for healthcare professionals and elements to assure a product’s safe use (“ETASU”). An ETASU can include, but is not limited to, special training or certification for prescribing or dispensing the product, dispensing the product only under certain circumstances, special monitoring and the use of patient-specific registries. The requirement for a REMS can materially affect the potential market and profitability of the product. Moreover, the FDA may require substantial post-approval testing and surveillance to monitor the product’s safety or efficacy.

Changes to some of the conditions established in an approved application, including changes in indications, labeling, or manufacturing processes or facilities, require submission and FDA approval of an NDA or BLA supplement or, in some case, a new application, before the change can be implemented. A supplement for a new indication typically requires clinical data similar to that in the original application, and the FDA uses the same procedures and actions in reviewing supplements as it does in reviewing NDAs and BLAs.

Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant orphan drug designation to drugs intended to treat a rare disease or condition, which is generally a disease or condition that affects fewer than 200,000 individuals in the United States, or more than 200,000 individuals in the United States but for which there is no reasonable expectation that the cost of developing and making the product for this type of disease or condition will be recovered from sales of the product in the United States.

Orphan drug designation must be requested before submitting an NDA. After the FDA grants orphan drug designation, the identity of the drug and its potential orphan use are disclosed publicly by the FDA. Orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.

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If a product that has orphan designation subsequently receives the first FDA approval for the disease or condition for which it has such designation, the product is entitled to a seven-year exclusive marketing period in the U.S. for that product, for that indication. During the seven-year exclusivity period, the FDA may not approve any other applications to market the same drug for the same disease, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity by means of greater effectiveness, greater safety, or providing a major contribution to patient care, or in instances of drug supply issues. Orphan drug exclusivity does not prevent the FDA from approving a different drug for the same disease or condition, or the same drug for a different disease or condition. Other benefits of orphan drug designation include tax credits for certain research and an exemption from the NDA user fee.

Expedited Development and Review Programs

The FDA is authorized to designate certain products for expedited review if they are intended to address an unmet medical need in the treatment of a serious or life-threatening disease or condition.

Fast Track Designation

Fast track designation may be granted for products that are intended to treat a serious or life-threatening disease or condition for which there is no effective treatment and preclinical or clinical data demonstrate the potential to address unmet medical needs for the condition. Fast track designation applies to both the product and the specific indication for which it is being studied. The sponsor of an investigational drug product may request that the FDA designate the drug candidate for a specific indication as a fast track drug concurrent with, or after, the submission of the IND for the drug candidate. The FDA must determine if the drug candidate qualifies for fast track designation within 60 days of receipt of the sponsor’s request. For fast track products, sponsors may have greater interactions with the FDA and the FDA may initiate review of sections of a fast track product’s NDA or BLA before the application is complete. This rolling review is available if the FDA determines, after preliminary evaluation of clinical data submitted by the sponsor, that a fast track product may be effective. The sponsor must also provide, and the FDA must approve, a schedule for the submission of the remaining information and the sponsor must pay applicable user fees. At the time of an NDA or BLA filing, the FDA will determine whether to grant priority review designation. Additionally, fast track designation may be withdrawn if the FDA believes that the designation is no longer supported by data emerging in the clinical trial process.

Breakthrough Therapy Designation

Breakthrough therapy designation may be granted for products that are intended, alone or in combination with one or more other products, to treat a serious or life-threatening condition and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over currently approved therapies on one or more clinically significant endpoints. Under the breakthrough therapy program, the sponsor of a new drug candidate may request that the FDA designate the candidate for a specific indication as a breakthrough therapy concurrent with, or after, the submission of an IND for the drug candidate. The FDA must determine if the drug product qualifies for breakthrough therapy designation within 60 days of receipt of the sponsor’s request. The FDA may take certain actions with respect to breakthrough therapies, including holding meetings with the sponsor throughout the development process, providing timely advice to the product sponsor regarding development and approval, involving more senior staff in the review process, assigning a cross-disciplinary project lead for the review team and taking other steps to design the clinical studies in an efficient manner.

Priority Review

Priority review may be granted for products that are intended to treat a serious or life-threatening condition and, if approved, would provide a significant improvement in safety and effectiveness compared to available therapies. The FDA will attempt to direct additional resources to the evaluation of an application designated for priority review in an effort to facilitate the review.

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Accelerated Approval

Accelerated approval may be granted for products that are intended to treat a serious or life-threatening condition and that generally provide a meaningful therapeutic advantage to patients over existing treatments. A product eligible for accelerated approval may be approved on the basis of either a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity or prevalence of the condition and the availability or lack of alternative treatments. In clinical trials, a surrogate endpoint is a measurement of laboratory or clinical signs of a disease or condition that substitutes for a direct measurement of how a patient feels, functions or survives. The accelerated approval pathway is most often used in settings in which the course of a disease is long, and an extended period of time is required to measure the intended clinical benefit of a product, even if the effect on the surrogate or intermediate clinical endpoint occurs rapidly. Thus, accelerated approval has been used extensively in the development and approval of products for treatment of a variety of cancers in which the goal of therapy is generally to improve survival or decrease morbidity and the duration of the typical disease course requires lengthy and sometimes large studies to demonstrate a clinical or survival benefit. The accelerated approval pathway is contingent on a sponsor’s agreement to conduct additional post-approval confirmatory studies to verify and describe the product’s clinical benefit. These confirmatory trials must be completed with due diligence and, in some cases, the FDA may require that the trial be designed, initiated and/or fully enrolled prior to approval. Failure to conduct required post-approval studies, or to confirm a clinical benefit during post-marketing studies, would allow the FDA to withdraw the product from the market on an expedited basis. All promotional materials for product candidates approved under accelerated regulations are subject to prior review by the FDA.

Even if a product qualifies for one or more of these programs, the FDA may later decide that the product no longer meets the conditions for qualification or the time period for FDA review or approval may not be shortened. Furthermore, fast track designation, breakthrough therapy designation, priority review and accelerated approval do not change the standards for approval but may expedite the development or approval process.

Pediatric Information

Under the Pediatric Research Equity Act (“PREA”), an NDA or BLA or supplements thereto must contain data to assess the safety and effectiveness of the product for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. The FDA may grant full or partial waivers, or deferrals, for submission of data. Unless otherwise required by regulation, PREA does not apply to any product for an indication for which orphan designation has been granted, with certain exceptions.

The Best Pharmaceuticals for Children Act (“BPCA”) provides NDA or BLA holders a six-month extension of any exclusivity—patent or nonpatent—for a product if certain conditions are met. Conditions for exclusivity include the FDA’s determination that information relating to the use of a new product in the pediatric population may produce health benefits in that population, the FDA making a written request for pediatric studies, and the applicant agreeing to perform, and reporting on, the requested studies within the statutory timeframe. Applications under the BPCA are treated as priority applications, with all of the benefits that designation confers.

Post-Approval Requirements

Once an NDA or BLA is approved, a product will be subject to certain post-approval requirements. For instance, the FDA closely regulates the post-approval marketing and promotion of biopharmaceutical products, including standards and regulations for direct-to-consumer advertising, off-label promotion, industry-sponsored scientific and educational activities and promotional activities involving the internet. Products may be marketed only for the approved indications and in a manner consistent with the approved labeling.

Adverse event reporting and submission of periodic reports are required following FDA approval of an NDA or BLA. The FDA also may require post-marketing testing, known as phase 4 testing, REMS, and surveillance to monitor the effects of an approved

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product, or the FDA may place conditions on an approval that could restrict the distribution or use of the product. In addition, quality control, drug manufacture, packaging and labeling procedures must continue to conform to cGMP after approval. Manufacturers and certain of their subcontractors are required to register their establishments with the FDA and certain state agencies. Registration with the FDA subjects entities to periodic unannounced inspections by the FDA, during which the Agency inspects manufacturing facilities to assess compliance with cGMP. Accordingly, manufacturers must continue to expend time, money and effort in the areas of production and quality-control to maintain compliance with cGMP. Regulatory authorities may withdraw product approvals or request product recalls if a company fails to comply with regulatory standards, if it encounters problems following initial marketing, or if previously unrecognized problems are subsequently discovered.

Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing processes or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information, imposition of post-market studies or clinical studies to assess new safety risks or imposition of distribution or other restrictions under a REMS program. Other potential consequences include, among other things:

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Restrictions on the marketing or manufacturing of the product, suspension of the approval, complete withdrawal of the product from the market or a product recall;

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Fines, warning or other enforcement-related letters or holds on post-approval clinical studies;

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Refusal of the FDA to approve pending applications or supplements to approved applications, or suspension or revocation of product license approvals;

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Product seizure or detention, or refusal to permit the import or export of products; or

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Injunctions or the imposition of civil or criminal penalties.

Patent Term Extension

The Hatch Waxman Amendments permit a patent term extension as compensation for patent term lost during the FDA regulatory review process. Patent term extension, however, cannot extend the remaining term of a patent beyond a total of 14 years from the product’s approval date. After approval, owners of relevant patents may apply for the extension. The allowable patent term extension is calculated as half of the product’s testing phase (the time between an IND application and an NDA or BLA submission) and all of the review phase (the time between NDA or BLA submission and approval) up to a maximum of five years. The time can be reduced for any time the FDA determines that the applicant did not pursue approval with due diligence.

The United States Patent and Trademark Office (“USPTO”), in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. However, the USPTO may not grant an extension because of, for example, failing to exercise due diligence during the testing phase or regulatory review process, failing to apply within applicable deadlines, failing to apply prior to expiration of relevant patents or otherwise failing to satisfy applicable requirements. Moreover, the applicable time period or the scope of patent protection afforded could be less than requested.

The total patent term after the extension may not exceed 14 years, and only one patent can be extended. The application for the extension must be submitted prior to the expiration of the patent, and for patents that might expire during the application phase, the patent owner may request an interim patent extension. An interim patent extension increases the patent term by one year and may be renewed up to four times. For each interim patent extension granted, the post-approval patent extension is reduced by one year. The director of the USPTO must determine that approval of the drug covered by the patent for which a patent extension is being sought is likely.

Coverage, Pricing, and Reimbursement

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In the United States and in foreign markets, sales of pharmaceutical products depend, in part, on the extent to which third-party payors provide coverage and establish adequate reimbursement levels for such products. In the United States, third-party payors include federal and state healthcare programs, private managed care providers, health insurers and other organizations. Adequate coverage and reimbursement from governmental healthcare programs, such as Medicare and Medicaid in the United States, and commercial payors are critical to new product acceptance.

There is significant uncertainty related to third-party payor coverage and reimbursement of newly approved products. In the United States, for example, principal decisions about reimbursement for new products are typically made by the Centers for Medicare & Medicaid Services (“CMS”), an agency within the U.S. Department of Health and Human Services (“HHS”). CMS decides whether and to what extent a new product will be covered and reimbursed under Medicare, and private third-party payors often follow CMS’s decisions regarding coverage and reimbursement to a substantial degree. In the United States, no uniform policy of coverage and reimbursement for products exists among third-party payors. Therefore, coverage and reimbursement for products can differ significantly from payor to payor. Decisions regarding the extent of coverage and amount of reimbursement to be provided for each of our product candidates will be made on a plan-by-plan basis. One payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage, and adequate reimbursement, for the product. Additionally, the coverage determination process is often a time-consuming and costly process that will require us to provide scientific and clinical support for the use of our product candidates to each payor separately, with no assurance that coverage and adequate reimbursement will be obtained. Coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which we or our collaborators receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

Increasingly, third-party payors are requiring that drug companies provide them with predetermined discounts from list prices and are challenging the prices charged for medical products. Further, such payors are increasingly challenging the price, examining the medical necessity and reviewing the cost effectiveness of medical product candidates. There may be especially significant delays in obtaining coverage and reimbursement for newly approved drugs. Third-party payors may limit coverage to specific product candidates on an approved list, known as a formulary, which might not include all FDA-approved drugs for a particular indication. Further, HHS imposes rebates on many Medicare Part B and Medicare Part D products to penalize price increases that outpace inflation on an annual basis. HHS has also been empowered to negotiate the price of certain single-source drugs that have been on the market for at least seven (7) years and biologics that have been on the market for at least eleven (11) years covered under Medicare as part of the Medicare Drug Price Negotiation Program. Each year up to twenty (20) products will be selected by HHS for the Medicare Drug Price Negotiation Program. Products subject to the Medicare Drug Price Negotiation Program are expected to experience a significant reduction in reimbursement from the Medicare program on a per unit basis.

Outside the United States, the commercialization of therapeutics is generally subject to extensive governmental price controls and other market regulations, and we believe the increasing emphasis on cost containment initiatives in Europe, Canada and other countries has, and will continue to, put pressure on the pricing and usage of therapeutics such as our product candidates.

Other Healthcare Laws

In addition to FDA restrictions on marketing of pharmaceutical products, several other types of state and federal laws have been applied to restrict certain general business and marketing practices in the pharmaceutical industry. These laws include anti-kickback statutes, false claims statutes and other healthcare laws and regulations.

The federal Anti-Kickback Statute prohibits, among other things, knowingly and willfully offering, paying, soliciting or receiving remuneration to induce, or in return for, purchasing, leasing, ordering or arranging for the purchase, lease or order of any healthcare item or service reimbursable under Medicare, Medicaid, or other federally financed healthcare programs. This statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on the one hand and prescribers, purchasers and formulary managers, among others, on the other. Although there are a number of statutory exceptions and regulatory safe harbors protecting certain common activities from prosecution or other regulatory sanctions, the exceptions and safe harbors are

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drawn narrowly, and practices that involve remuneration intended to induce prescribing, purchases or recommendations may be subject to scrutiny if they do not qualify for an exception or safe harbor. In addition, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to commit a violation.

Federal civil and criminal false claims laws, including the federal civil False Claims Act, prohibit any person or entity from knowingly presenting, or causing to be presented, a false claim for payment to the federal government, or knowingly making, or causing to be made, a false statement to have a false claim paid. This includes claims made to programs where the federal government reimburses, such as Medicare and Medicaid, as well as programs where the federal government is a direct purchaser, such as when it purchases off the Federal Supply Schedule. Recently, several pharmaceutical and other healthcare companies have been prosecuted under these laws for allegedly inflating drug prices they report to pricing services, which in turn were used by the government to set Medicare and Medicaid reimbursement rates, and for allegedly providing free product to customers with the expectation that the customers would bill federal programs for the product. In addition, certain marketing practices, including off-label promotion, may also violate false claims laws. Additionally, the government may assert that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the federal civil False Claims Act. Most states also have statutes or regulations similar to the federal Anti-Kickback Statute and civil False Claims Act, which apply to items and services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payor.

Other federal statutes pertaining to healthcare fraud and abuse include the civil monetary penalties statute, which prohibits, among other things, the offer or payment of remuneration to a Medicaid or Medicare beneficiary that the offeror or payor knows or should know is likely to influence the beneficiary to order a receive a reimbursable item or service from a particular supplier, and the additional federal criminal statutes created by the Health Insurance Portability and Accountability Act of 1996 (“HIPAA”), which prohibits, among other things, knowingly and willfully executing or attempting to execute a scheme to defraud any healthcare benefit program or obtain by means of false or fraudulent pretenses, representations or promises any money or property owned by or under the control of any healthcare benefit program in connection with the delivery of or payment for healthcare benefits, items or services. Similar to the federal Anti-Kickback Statute, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to commit a violation.

Further, pursuant to the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation (the “Affordable Care Act” or the “ACA”), CMS has issued a final rule that requires manufacturers of prescription drugs to collect and report information on certain payments or transfers of value to physicians (defined to include doctors, dentists, optometrists, podiatrists and chiropractors), other healthcare professionals (such as physicians assistants and nurse practitioners), and teaching hospitals, as well as investment interests held by physicians and their immediate family members. The reports must be submitted on an annual basis. The reported data is made available in searchable form on a public website on an annual basis. Failure to submit required information may result in civil monetary penalties.

HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act and its implementing regulations, imposes obligations, including mandatory contractual terms, on covered entities, business associates and their covered subcontractors with respect to safeguarding the privacy, security and transmission of individually identifiable health information.

In addition, several states now require prescription drug companies to report certain expenses relating to the marketing and promotion of drug products and to report gifts and payments to individual healthcare practitioners in these states. Other states prohibit various marketing-related activities, such as the provision of certain kinds of gifts or meals. Still other states require the posting of information relating to clinical studies and their outcomes. Some states require the reporting of certain drug pricing information, including information pertaining to and justifying price increases. In addition, certain states require pharmaceutical companies to implement compliance programs and/or marketing codes. Certain states and local jurisdictions also require certain regulatory licenses to manufacture or distribute products commercially and/or the registration of pharmaceutical sales and medical representatives. Compliance with these laws is difficult and time consuming, and companies that do not comply with these state laws may face significant penalties.

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Efforts to ensure that business arrangements with third parties comply with applicable healthcare laws and regulations involve substantial costs. If a drug company’s operations are found to be in violation of any such requirements, it may be subject to significant penalties, including civil, criminal and administrative penalties, damages, fines, disgorgement, imprisonment, the curtailment or restructuring of its operations, loss of eligibility to obtain approvals from the FDA, exclusion from participation in government contracting, healthcare reimbursement or other federal or state government healthcare programs, including Medicare and Medicaid, integrity oversight and reporting obligations, imprisonment, and reputational harm. Although effective compliance programs can mitigate the risk of investigation and prosecution for violations of these laws, these risks cannot be entirely eliminated. Any action for an alleged or suspected violation can cause a drug company to incur significant legal expenses and divert management’s attention from the operation of the business, even if such action is successfully defended.

U.S. Healthcare Reform

In the United States there have been, and continue to be, proposals by the federal government, state governments, regulators and third-party payors to control or manage the increased costs of health care and, more generally, to reform the U.S. healthcare system. The pharmaceutical industry has been a particular focus of these efforts and has been significantly affected by major legislative initiatives. For example, in March 2010, the ACA was enacted, substantially changed the way healthcare is financed by both governmental and private insurers.

There have been judicial, executive brand, and Congressional challenges and amendments to certain aspects of the ACA. For example, on July 4, 2025, the One Big Beautiful Bill Act the (“OBBBA”) was signed into law, which narrowed access to ACA marketplace exchange enrollment and declined to extend the ACA enhanced advanced premium tax credits that expired at the end of 2025, which, among other provisions in the law, are anticipated to reduce the number of Americans with health insurance. The OBBBA also is expected to reduce Medicaid spending and enrollment by implementing work requirements for some beneficiaries, capping state-directed payments, reducing federal funding, and limiting provider taxes used to fund the program. Congress is considering proposed legislation intended to further reduce healthcare costs with alternatives to replace the expired ACA subsidies.

In addition, other legislative changes have been proposed and adopted in the United States since the ACA was enacted to reduce healthcare expenditures. These changes include aggregate reductions to Medicare payments to providers of 2% per fiscal year, which began in 2013 and will remain in effect until 2032 unless additional Congressional action is taken.

The current administration is pursuing policies to reduce regulations and expenditures across government agencies including at HHS, the FDA, CMS and related agencies. These actions, presently directed by executive orders or memoranda from the Office of Management and Budget, may propose policy changes that create additional uncertainty for our business. For example, the current administration has announced agreements with several pharmaceutical companies that require the drug manufacturers to offer, through a direct to consumer platform (“TrumpRx”) U.S. patients and Medicaid programs prescription drug Most-Favored Nation pricing equal to or lower than those paid in other developed nations, with additional mandates for direct-to-patient discounts and repatriation of foreign revenues. Other recent actions, for example, include (1) directing agencies to reduce agency workforce and cut programs; (2) directing HHS and other agencies to lower prescription drug costs through a variety of initiatives; (3) imposing tariffs on imported pharmaceutical products; and (4) as part of the Make America Healthy Again Commission’s Strategy Report released in September 2025, working across government agencies to increase enforcement on direct-to-consumer pharmaceutical advertising. Additionally, the current administration recently called on Congress to enact "The Great Healthcare Plan," to codify and expand Most-Favored Nation pricing, lower government subsidies to private insurance companies, increase healthcare price transparency, expand pharmaceutical drugs available for over-the-counter purchase, and enact restrictions on pharmacy benefit manager (“PBM”) payment methodologies, among other things. These actions and policies may significantly reduce U.S. drug prices, potentially impacting manufacturers’ global pricing strategies and profitability, while increasing their operational costs and compliance risks. In June 2024, the U.S. Supreme Court’s Loper Bright decision greatly reduced judicial deference to regulatory agencies, which could increase successful legal challenges to federal regulations affecting our operations. Congress may introduce and ultimately pass health care related legislation that could impact the drug approval process and make changes to the Medicare Drug Price Negotiation Program. At the state level, legislatures are increasingly passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient

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reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

Employees and Human Capital Resources

As of March 1, 2026, we had four employees, including four full-time employees and three holding Ph.D., MBA and/or M.S. degrees. Our employees have established internal expertise in cellular biology, pre-clinical development, and early-to-late-stage clinical development, as well as finance, business development and strategic transactions. None of our employees are represented by a labor union or covered by collective bargaining agreements. We will continue to add experienced and talented scientists in areas, such as medicinal chemistry, that we believe are critical for the discovery of highly differentiated small-molecule compounds.

We consider a number of measures and objectives in managing our human capital assets, including, among others, employee engagement, development and training, talent acquisition and retention, employee safety and wellness, diversity and inclusion, and compensation and pay equity. We provide our employees with salaries and bonuses intended to be competitive for our industry, opportunities for equity ownership, development programs that enable continued learning and growth and a benefits package to promote well-being across all aspects of their lives, including health care, retirement planning and paid time off. The principal purposes of our equity incentive plans are to attract, retain and motivate selected employees, consultants and directors through the granting of equity-based compensation awards and cash-based compensation awards, in order to increase stockholder value and the success of our company by motivating such individuals to perform to the best of their abilities and achieve our objectives.

We believe that a diverse workforce is important to our success and we are fundamentally committed to creating and maintaining a work environment in which employees are treated fairly, with dignity, decency, respect and in accordance with all applicable laws. We understand that varied perspectives lead to the best ideas and outcomes. We believe that by creating a workplace where every individual can feel welcome and valued, we will be better able to achieve our corporate objectives. All employees must adhere to a code of business conduct and ethics and our employee handbook, which combined, define standards for appropriate behavior. Our recruitment, hiring, development, training, compensation, and advancement is based on qualifications, performance, skills, and experience without regard to gender, gender identity, sexual orientation, race, or ethnicity. People of color and those who are part of underrepresented groups in the biotech industry are encouraged to apply for open positions.

Corporate Information

We were incorporated in Delaware in April 2011. Our corporate headquarters are located at 2000 Sierra Point Parkway, Suite 400, Brisbane, California 94005, and our telephone number is (415) 798-8589.

Available Information

Our internet website address is www.tempesttx.com. In addition to the information about us and our subsidiaries contained in this Annual Report, information about us can be found on our website. Our website and information included in or linked to our website are not part of this Annual Report.

Our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, are available free of charge through our website as soon as reasonably practicable after they are electronically filed with or furnished to the Securities and Exchange Commission (“SEC”). Additionally, the SEC maintains an internet site that contains reports, proxy and information statements and other information. The address of the SEC’s website is www.sec.gov.

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