NASDAQ: PRLD

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The following table summarizes our product candidate pipeline:

Prelude Discovery and Development Approach

We carefully evaluate and select our targets based on three key pillars, which provide a framework for optimizing our drug discovery and development efforts.

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Identify target mechanisms with a compelling biological rationale

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Current target mechanisms of focus include transcriptional regulation and uncontrolled cell proliferation signaling mediated by well characterized driver mutations.

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Leverage our advanced medicinal chemistry capabilities to create better product candidates

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We leverage multiple modalities (inhibitors, degraders, and antibody-drug conjugates) in order to deliver clinical candidates that meet our desired target product profiles. Clinical candidates from all programs to-date have been internally designed and developed.

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Pursue targets that drive cancers with high unmet need

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Focus on targets that allow us to select patients and cancers with high unmet need with no approved therapies, or patient populations that are underserved by approved treatments.

Once we have identified optimal targets using the three pillars above, we engage our unique discovery engine to invent and develop molecules rapidly and efficiently. We believe our expertise, capabilities and experience to select potentially high value biological targets and invent molecules with an optimized balance of biological and chemical properties differentiates us from others in the precision oncology space.

We design our clinical trials to leverage the potential broad utility of our compounds with a focus on efficient regulatory pathways to enable our potentially transformative medicines, aiming to quickly reach patients with high unmet medical need. By focusing on what we believe are clinically validated targets with a clear path to differentiation and early clinical proof-of-concept, we seek to advance our programs through expedited approval processes, as available. We believe that we can generate proof-of-concept clinical data to guide our future regulatory pathways to approval.

Our Strategy

We aim to create better targeted and more effective cancer therapies. Our goal is to transform the lives of patients with cancer by leveraging the core competencies of our experienced team in medicinal chemistry, cancer biology and clinical

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development to bring novel drugs to market. We intend to become a fully integrated oncology company on the foundation of drug discovery excellence to deliver novel precision oncology medicines to patients with underserved cancers by pursuing the following objectives:

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Leverage our cancer biology and medicinal chemistry expertise

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Discover and develop first or best-in-class differentiated development candidates that address unmet needs of oncology patients.

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Rapidly progress our product candidates through clinical development in patients with solid tumors and hematological malignancies.

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Focus clinical development on underserved cancers and design clinical trials that allow for efficient decision-making with the highest probability of success and potential for rapid regulatory approval.

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Advance our product candidate pipeline in combination with internally discovered and third-party developed compounds.

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Evaluate strategic opportunities to accelerate development timelines and maximize the value of our product candidates.

Our Product Candidates

JAK2V617F

Background

JAK2V617F is the primary driver mutation responsible for disease progression in the majority of patients living with myeloproliferative neoplasms (MPNs). The mutation impacts approximately 95% of patients with polycythemia vera (PV), 60% of patients with essential thrombocythemia (ET) and 55% of patients with myelofibrosis (MF). Identifying JAK2 JH2 inhibitors that selectively target V617F+ cells has long been a shared goal and challenge for industry. If successful, this approach has potential to reduce mutant allele burden, modify disease progression, and transform treatment outcomes for MPN patients.

Our JAK2V617F Program

We have designed and identified novel allosteric inhibitors that bind into the JAK2 JH2 “deep pocket” where the V617F mutation resides. These candidates demonstrate mutant specific inhibition in multiple preclinical models of MPNs. We believe this approach may have the potential to reduce mutant allele burden, slow or even reverse disease progression, and transform treatment outcomes for MPN patients.

PRT12396, our lead, mutant-selective JAK2V617F inhibitor received IND clearance from the U.S. FDA, as announced in February 2026 and we anticipate initiating a Phase 1 study in the second quarter of 2026.

This program is the subject of an Exclusive Option Agreement (the “Option Agreement”) with Incyte Corporation (“Incyte”) as announced on November 4, 2025. Under the Option Agreement, Incyte received an exclusive option to acquire our entire right, title, and interest in and to certain assets, properties, and rights related to the Program, including our library of preclinical candidates (collectively, the “Transferred Assets”).

The Option Agreement included, as an exhibit, the form of an Asset Purchase Agreement (the “APA”), which contemplates the sale, transfer, assignment, and conveyance by us to Incyte, and the purchase, acquisition, and assumption by Incyte from us, of the our entire right, title, and interest in and to the Transferred Assets in the event Incyte exercises its option under the Option Agreement.

At any time commencing on the effective date of the Option Agreement until a maximum of 18 months from the effective date (the “Option Period”), Incyte may elect to exercise its exclusive option to acquire the Program and associated assets from us pursuant to the APA for $100 million. We are continuing to advance the Program during the Option Period. We received $60 million in capital upon signing the Option Agreement, comprised of an initial payment of $35 million in cash, plus a $25 million equity investment by Incyte. Under the APA, we would be eligible to receive up to $775 million in additional clinical and regulatory milestones, and single digit royalties on global net sales. Combined, total potential cash payments from the transaction could reach up to $910 million.

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We continue to own and develop all program assets during the Option Period. If the option is exercised during the Option Period and the parties enter into and close the transaction set forth in the APA, Incyte will own all Transferred Assets subject to our right, in our sole discretion and cost, to continue to conduct development activities during the Option Period to nominate and select additional development candidate(s) for the Program. If Incyte elects to not exercise its option to acquire the Program or close the transaction, all JAK2 V617F program assets would remain in our sole ownership and control.

KAT6A

Background

There is a high unmet need for novel modalities to treat advanced breast cancer & other solid tumors. KAT6A and KAT6B are part of the 8p11 amplicon and histone acetyltransferase (HAT) complex which regulates the expression of a number of genes involved in regulating cancer cell growth and survival, including the estrogen receptor (ER), progesterone receptor (PR) and MYC. KAT6A amplification and overexpression in cancer leads to increased activity and because KAT6A regulates the expression of ER, MYC and other cell cycle genes, its increased activity drives ER+ BC growth. Although KAT6A overexpression drives cancer growth, both KAT6A and its related family member KAT6B are important in normal hematopoiesis and preclinical data demonstrate that loss of both KAT6A and B results in bone marrow toxicity.

Our KAT6 Selective Degrader Program

Our approach of selectively degrading KAT6A has the potential to deliver differentiated safety and efficacy over non-selective KAT6A/B inhibitors. Our preclinical data demonstrate that selective KAT6A degradation shows robust efficacy in ER+ BC models. Our lead KAT6A degrader is a highly potent degrader of KAT6A with selectivity for KAT6A over KAT6B of greater than 1000 fold. We have observed oral PK across all species, and in vivo efficacy as monotherapy with complete regressions observed at well-tolerated, low once daily oral doses in preclinical models of KAT6A amplified and non-amplified ER+ BC.

We have selected a development candidate and remain on track to file an IND in mid-2026 with Phase 1 study initiation anticipated in the second half of 2026.

Other Discovery Programs

As mentioned above, our goal is to transform the lives of patients with cancer by leveraging the core competencies of our experienced team in medicinal chemistry, cancer biology and clinical development to bring novel drugs to market. As such, our discovery programs include the following:

Mutated Calreticulin (mCALR) degrader antibody conjugates (DACs)

Mutant CALR is a neoantigen presented on the cell surface of malignant myeloid cells but not normal cells and is found in approximately 25-35% of patients with myelofibrosis (MF) and essential thrombocythemia (ET). Current therapies for MPNs provide symptom relief but do not reduce allele burden, and are not curative and identification of therapeutic approaches that can selectively eliminate mutant CALR disease-initiating progenitors is an unmet medical need. Recently, an mCALR-targeted monoclonal antibody demonstrated robust clinical activity in high-risk ET patients. We are seeking to further optimize this modality by developing mCALR-targeted DACs using our proprietary degrader payloads.

SMARCA2/4 and CDK9 degraders are both highly active in CALR mutated MPN cell lines and can be used as payloads for mCALR-targeted DACs. mCALR-targeted DACs, delivering our degrader payloads to disease-initiating clones have the potential to be first-in-class, disease modifying therapies.

Precision Antibody Drug Conjugates (ADCs)

Background

Among ADCs in the clinic, “Precision ADCs” with novel degrader payloads are only now emerging. Most “Next Gen” ADCs in the clinic are still using older cytotoxics as payloads, with similar liabilities and limited scope for diversification. Targeted protein degraders (TPD) are uniquely suited as payloads with exquisite potencies and added benefit of targeting precision biological pathway. Novel TPD payloads can be designed with properties to avoid exposure to healthy tissues such

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as low cell penetration and high plasma clearance. Precision ADCs with degrader-prodrug payloads have the potential to confer both improved efficacy and improved tolerability.

In 2023, we entered into a multi-year, multi-program agreement with AbCellera Biologics Incorporated ("AbCellera") to jointly discover, develop, and commercialize novel degrader antibody conjugates (“DACs”) for up to five programs (the "Collaboration Agreement"). We believe the Collaboration Agreement will allow us to combine our small molecules and degraders expertise with their antibody expertise to develop precision antibody drug conjugates. As one of our first precision ADC programs, we and our partner AbCellera began work on an early-stage discovery program involving potent degraders of the SMARCA family of proteins as payloads for novel antibodies targeting tumor specific antigens. Given the potent anti-tumor activity of these molecules in pre-clinical models of cancers, we believe that these precision ADCs have the potential to extend the therapeutic utility of this class. The partnership includes up to five precision ADC targets. Under the terms of the agreement, AbCellera will lead manufacturing activities and the Company will lead clinical development and global commercialization, subject to AbCellera’s option to co-promote any resulting commercial products in the United States.

During the third quarter of 2025 we amended our collaboration with AbCellera (the "Amended Agreement") and, subsequently in October 2025, further expanded the collaboration (the "Expanded License Agreement"). The Amended Agreement and Expanded License Agreement provided AbCellera a non-exclusive license to use certain of our degrader payloads to independently discover, develop and commercialize a select number of DACs against undisclosed antibody targets. The agreements also entailed other changes to overall resource allocation and collaboration governance. For the newly licensed DAC programs, AbCellera received world-wide rights to lead and fully control the licensed programs at its sole cost and expense and we are not responsible for any additional financial responsibilities or go forward development costs associated with those programs. We received an upfront non-refundable payment from AbCellera of $6.5 million in the third quarter of 2025 upon signing the Amended Agreement and an upfront non-refundable payment of $6 million in October 2025 upon signing of the Expanded License Agreement. For the additional licensed DACs, we are also eligible to receive customary downstream milestones and single digit royalties on future product sales. The original Collaboration Agreement, whereunder the companies can jointly discover, develop, and commercialize novel DACs for up to five programs remains in effect.

Outside of the AbCellera collaboration, we have discovered and optimized a number of pre-clinical precision payloads. We disclosed first data about these precision payloads at the 36th EORTC-NCI-AACR Symposium describing preclinical proof-of-concept using a novel, potent SMARCA2/4 dual degrader as a “Precision Payload” conjugated to multiple antibodies. Our SMARCA2/4 dual degraders have shown picomolar potency with potential for increased efficacy, selectivity and improved therapeutic index across a wide range of cancer types.

With this experience, we have developed a degrader payload platform, designed and engineered to improve efficacy and tolerability, as compared to traditional cytotoxic payloads. Our potent and cell line selective targeted protein degraders are designed to be highly effective payloads. Payload permeability is maintained to provide an intact bystander effect for enhanced tumor kill. Prodrugs of the degrader payloads are engineered to have no membrane permeability to limit systemic toxicity. Payloads are engineered to have high clearance in vivo to help reduce systemic toxicity. In addition, highly stable degraders have the potential to provide improved efficacy. Accordingly, we believe that precision ADCs have the potential to deliver both improved efficacy and improved tolerability across several cancer types.

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SMARCA2 (BRM) selective degrader program

Background

SMARCA2, or BRM, and its related family member, SMARCA4, or BRG1, are the enzymatic subunits of the SWI/SNF complex that regulates gene expression by allowing the DNA to be accessible for transcription to mature RNA, a process known as chromatin remodeling. SMARCA4 is mutated in multiple cancers, including 10-12% of NSCLC, resulting in loss of SMARCA4 protein. Because the activity of either SMARCA2 or SMARCA4 is required for chromatin remodeling to occur, the SMARCA4-deficient cancer cells become highly dependent on SMARCA2 for their survival. Therefore, we believe targeting SMARCA2 in SMARCA4-deficient cancers will produce a strong synthetic lethality, resulting in SMARCA4 mutant tumor cell death while sparing normal cells that express SMARCA4 protein.

Our SMARCA2 Selective Degrader Program

A molecule capable of targeting a protein for degradation (degrader) typically contains a binding element to a targeted protein of interest (SMARCA2), a chemical linker and an E3 ligase binding element which allows for the formation of a ternary complex between the target, the degrader and the E3 ligase that induces ubiquitination and subsequent degradation of the targeted protein. Selectivity can be achieved, not only by the selective binding to the target (SMARCA2), but also through the optimization of the unique ternary complexes formed by the target (SMARCA2) versus its homologous protein (SMARCA4). PRT3789 is a first-in-class, highly selective degrader of SMARCA2 protein, which along with SMARCA4 controls gene regulation through chromatin remodeling. PRT7732 is >1000-fold selective for SMARCA2 vs. SMARCA4 and demonstrates robust activity in SMARCA4 deficient preclinical cancer models both as monotherapy and in combination with docetaxel at well-tolerated doses.

On November 4, 2025 we announced that we decided to pause the clinical development of our SMARCA2 degrader program which is comprised of PRT3789 and PRT7732 and prioritize allocation of resources to advancing the JAK2 V617F and KAT6A selective degrader programs.

Intellectual Property

We strive to protect the proprietary technologies that we believe are important to our business, including seeking and maintaining patent protection intended to cover the compositions of matter of our product candidates, their methods of use, related technology, and other inventions that are important to our business.

Our success will depend significantly on our ability to obtain and maintain patent and other proprietary protection for commercially important technology, inventions, and know-how related to our business, to defend and enforce our patents, to preserve the confidentiality of our trade secrets, and to operate without infringing valid and enforceable patents and other proprietary rights of third parties. We also rely on know-how and continuing technological innovation to develop, strengthen, and maintain our proprietary position in the field of precision oncology.

As more fully described below, our patent portfolio includes, inter alia, patent families with claims directed to compositions of matter for, and methods of using our compounds. The patent portfolio currently comprises of 282 patents and patent applications:

(A)(i) 14 issued U.S. patents, (ii) 28 U.S. non-provisional patent applications, and (iii) 19 U.S. provisional patent applications; and

(B)(iv) 21 PCT patent applications, (v) 59 issued foreign patents including patents in European jurisdictions, and (vi) 141 foreign patent applications.

As of the present filing, a total of 14 U.S. patents have been issued, which are wholly owned by us.

In addition to our filings in the U.S., we own patents and pending patent applications in Australia, Brazil, Canada, China, Eurasia, Europe, Hong Kong, India, Israel, Japan, Mexico, New Zealand, South Africa, South Korea, and Ukraine.

The term of individual patents depends upon the legal term of the patents in the countries in which they are obtained. In the countries in which we file, the patent term is 20 years from the earliest non-provisional filing date, subject to any disclaimers or extensions. The term of a patent in the United States can be adjusted due to any failure of the United States Patent and Trademark Office following certain statutory and regulation deadlines for issuing a patent.

In the United States, the patent term of a patent that covers an FDA-approved drug may also be eligible for patent term extension, which permits patent term restoration as compensation for a portion of the patent term lost during the FDA regulatory review process. The Hatch-Waxman Act permits a patent term extension of up to five years beyond the original

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expiration of the patent, subject to certain limits and calculations. The protection provided by a patent varies from country to country, and is dependent on the type of patent granted, the scope of the patent claims, and the legal remedies available in a given country.

Obtaining patent protection is not the only method that we employ to protect our proprietary rights. We also utilize other forms of intellectual property protection, including trademark, copyright, and trade secrets, when those other forms are better suited to protect a particular aspect of our intellectual property. Our belief is that our proprietary rights are strengthened by our comprehensive approach to intellectual property protection. It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers, and other advisors to execute confidentiality agreements upon the commencement of employment or consulting relationships with us. These agreements provide that all confidential information concerning our business or financial affairs developed or made known to the individual during the course of the individual’s relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. In the case of employees, the agreements provide that all inventions conceived by the individual, and which are related to our current or planned business or research and development or made during normal working hours, on our premises or using our equipment or proprietary information, are our exclusive property.

Manufacturing

We do not own or operate, and currently have no plans to establish, any manufacturing facilities. We currently rely, and expect to continue to rely for the foreseeable future, on third parties for the manufacture of our product candidates for preclinical and clinical testing, including pharmaceutical ingredients and clinical drug supply, as well as for commercial manufacture of any drugs that we may commercialize. We obtain our supplies from these manufacturers on a purchase order basis and do not have long-term supply arrangements in place. We do not own in-house warehouse facilities. We rely on third parties for storage and distribution of drug substance and drug product. We do not currently have arrangements in place for redundant supply for active pharmaceutical ingredients and drug product. As our development programs progress and we build new process efficiencies, we expect to continually evaluate this strategy with the objective of satisfying demand for registration trials and, if approved, the manufacture, sale and distribution of commercial products.

Commercialization

Given our stage of development, we have not yet established a commercial organization or distribution capabilities. If we are successful in obtaining the necessary regulatory approval, we may pursue commercialization on our own or seek to collaborate with a third party for commercialization, particularly outside the United States.

The biotechnology and pharmaceutical industries are characterized by the rapid evolution of technologies and understanding of disease etiology, intense competition and a strong emphasis on intellectual property. We believe that our approach, strategy, scientific capabilities, know-how and experience provide us with competitive advantages. However, we expect substantial competition from multiple sources, including major pharmaceutical, specialty pharmaceutical, and existing or emerging biotechnology companies, academic research institutions and governmental agencies and public and private research institutions worldwide. Many of our competitors, either alone or through collaborations, have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and patient enrollment in clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs. As a result, our competitors may discover, develop, license or commercialize products before or more successfully than we do.

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Competition

We face competition from segments of the pharmaceutical, biotechnology and other related markets that pursue the development of precision oncology therapies optimized to target the key driver mechanisms in cancers with high unmet need.

For our JAK2V617F inhibitor program, competition includes Ajax Therapeutics, Atavistik Bio, Cogent Biosciences, Eilean Therapeutics, Incyte Corporation, Llydlaw Therapeutics, Rathyra Therapeutics, and V6 Therapeutics. These companies have publicly disclosed their research and development efforts in this area.

For our KAT6A degrader program, other companies, including Pfizer, Olema Oncology, Menarini Group, BeOne Medicines (f/k/a BeiGene), Ideaya Biosciences, Isosterix, ProtAI, and Beijing Konruns Pharmaceutical have publicly disclosed their research and development efforts in this area.

More broadly, several global biopharmaceutical companies have prioritized precision oncology as an area of strategic focus, including but not limited to Amgen Inc., AbbVie Inc., AstraZeneca PLC, Astellas Inc., Bayer AG, Boehringer Ingelheim AG, Bristol Myers Squibb, Inc., Daiichi Sankyo Inc., Eli Lilly and Company, Inc., F. Hoffman-La Roche, Gilead Sciences Inc., GlaxoSmithKline PLC, Johnson & Johnson Services, Inc., Merck & Co. Inc., Novartis AG, and Pfizer Inc. In addition, there are multiple smaller biotech companies focused on discovery and development of precision oncology medicines, including but not limited to Arvinas Inc., Aurigene, Black Diamond Therapeutics, Inc., C4 Therapeutics, Foghorn Therapeutics Inc., Ideaya Biosciences, Kura Oncology, Inc., Kymera Therapeutics Inc., Nuvation Bio Inc., Repare Therapeutics Inc., Revolution Medicines, Inc., Relay Therapeutics, Inc., Tango Therapeutics, Inc., and Zentalis Pharmaceuticals, Inc.

We could see a reduction or elimination in our commercial opportunity if our competitors develop and commercialize drugs that are safer, more effective, have fewer or less severe side effects, are more convenient to administer, are less expensive or with more favorable labeling than our product candidates. Our competitors also may obtain FDA or other regulatory approval for their drugs more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market. The key competitive factors affecting the success of all of our product candidates, if approved, are likely to be their efficacy, safety, convenience, price, the level of generic competition and the availability of reimbursement from government and other third-party payors.

Government Regulation

Government authorities in the U.S., 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, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting, and import and export of pharmaceutical products such as those we are developing. The processes for obtaining regulatory approvals in the United States and in foreign countries and jurisdictions, along with subsequent compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources.

FDA Approval Process

In the U.S., pharmaceutical products are subject to extensive regulation by the FDA, under the Federal Food, Drug, and Cosmetic Act, or FD&C Act, and other federal and state statutes and regulations governing, 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 pharmaceutical 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, or NDAs, warning or untitled letters, inspectional findings product recalls, product seizures, import detention, total or partial suspension of production or distribution, injunctions, fines, civil penalties and criminal prosecution. We may also be debarred by the FDA, excluded, deemed to be ineligible, or debarred from government contracting, or excluded from participation in government healthcare programs. Regulatory requirements governing our business are evolving. FDA also continually issues guidance documents that provide FDA’s interpretation of its laws and regulations, as well as FDA’s approach to scientific issues and questions. For instance, with respect to cancer,

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FDA has issued a number of guidances with respect to patient reported outcomes, clinical trial eligibility criteria, dose optimization, and multiregional clinical trials.

Pharmaceutical product development for a new product or certain changes to an approved product in the U.S. typically involves preclinical laboratory and animal tests, the submission to FDA of an IND which must become effective before clinical testing in the U.S. may commence, and adequate and well-controlled clinical trials to establish the safety and effectiveness of the drug for each indication for which FDA approval is sought. Satisfaction of FDA pre-market approval requirements typically takes many years and the actual time required may vary substantially based upon the type, complexity and novelty of the product or disease.

Preclinical tests include laboratory evaluation of product chemistry, formulation and toxicity, as well as animal trials to assess the characteristics and potential safety and efficacy of the product. The conduct of the preclinical tests must comply with federal regulations and requirements, including Good Laboratory Practice, or GLP, regulations and other applicable laws or regulations. In 2025, however, FDA announced a plan to reduce animal testing, with an initial focus on monoclonal antibodies. The results of preclinical testing are submitted to FDA as part of an IND along with other information, including information about product chemistry, manufacturing and controls, a proposed clinical trial protocol, and any available clinical data or literature on the product candidate. Long-term preclinical tests, such as animal tests of reproductive toxicity and carcinogenicity, may continue after the IND is submitted. A 30-day waiting period after the submission of each IND is required prior to the commencement of clinical testing in humans. If FDA has not placed the study on clinical hold within this 30-day period, the clinical trial proposed in the IND may begin.

Clinical trials involve the administration of the investigational new drug to healthy volunteers or patients under the supervision of a qualified investigator. Clinical trials must be conducted: (i) in compliance with federal regulations; (ii) in compliance with Good Clinical Practice, or 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 the objectives of the trial, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. Each protocol involving testing on U.S. patients and subsequent protocol amendments must be submitted to FDA as part of the IND. Sponsors will also be required to provide FDA with diversity action plans once such requirements go into effect.

FDA may order the temporary, or permanent, discontinuation of a clinical trial at any time, or impose other sanctions, if it believes that the clinical trial either is not being conducted in accordance with FDA requirements or presents an unacceptable risk to the clinical trial patients. Imposition of a clinical hold may be full or partial. The study protocol and informed consent information for patients in clinical trials must also be submitted for approval to an institutional review board, or IRB, and ethics committee for approval. An IRB considers among other things, whether the risks to individuals participating in the trials are minimized and are reasonable in relation to anticipated benefits, and whether the planned human subject protections are adequate. The IRB will also monitor the clinical trial until completed. An IRB may also require the clinical trial at the site to be halted, either temporarily or permanently, for failure to comply with the IRB’s requirements, or may impose other conditions. Progress reports detailing the results of the clinical trials must be submitted at least annually to FDA and the IRB and more frequently if serious adverse events or other significant safety information is found. 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. Subjects participating in clinical trials must also provide their informed consent on the IRB approved form.

Clinical trials to support NDAs for marketing approval are typically conducted in three sequential phases. In Phase 1, the initial introduction of the drug into healthy human subjects or patients, the drug is tested to assess metabolism, pharmacokinetics, pharmacological actions, mechanism of action, absorption, metabolism distribution, excretion, side effects associated with increasing doses, and, if possible, early evidence of effectiveness. Phase 2 usually involves trials in a limited patient population to determine the effectiveness of the drug for a particular indication, dosage tolerance and optimum dosage, and to identify common adverse effects and safety risks. If a drug demonstrates evidence of effectiveness and an acceptable safety profile in Phase 2 evaluations, Phase 3 trials are undertaken to obtain the additional information about clinical efficacy and safety in a larger number of patients, typically at geographically dispersed clinical trial sites, to permit FDA to evaluate the overall benefit-risk relationship of the drug and to provide adequate information for the labeling of the drug. The FDA typically requires that product marketing applications include data from adequate and well controlled clinical trials, which provide substantial evidence of efficacy. In some instances, FDA may condition approval of an NDA on the applicant’s agreement to conduct additional clinical trials to further assess the product’s safety and effectiveness after approval, to answer unresolved questions. Such post-approval trials are typically referred to as Phase 4 studies. The results of Phase 4 studies can confirm or refute the effectiveness of a product candidate and can provide important safety information.

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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).

The manufacture of investigational drugs for the conduct of human clinical trials is subject to current Good Manufacturing Practice, or cGMP requirements. Investigational drugs and active ingredients substances imported into the United States are also subject to FDA regulation. Further, the export of investigational products outside the United States is subject to regulatory requirements of the receiving country as well as U.S. export requirements under the FDCA.

Concurrent with clinical trials, companies usually complete additional nonclinical studies and must also develop additional information about the physical characteristics of the product candidate and finalize a manufacturing process for the product candidate in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the product candidate. Further, appropriate packaging must be selected and tested and adequate stability studies must be conducted to demonstrate that the product candidate does not undergo unacceptable deterioration over its shelf life.

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.

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. Investigators must also report certain conflicts of interest to the clinical study sponsor, which the clinical study sponsor must report to FDA.

After completion of the required clinical testing, an NDA is prepared and submitted to FDA. FDA approval of the NDA is required before marketing of the product may begin in the U.S. The NDA 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.

The cost of preparing and submitting an NDA is substantial. The submission of most NDAs is additionally subject to a substantial application user fee. 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, provided that certain very specific qualifying criteria are met. Additionally, no application user fees are assessed on NDAs for products designated as orphan drugs, unless the product also includes a non-orphan indication. The applicant under an approved NDA is also subject to annual program fees. The FDA adjusts the user fees on an annual basis, and the fees typically increase annually.

FDA reviews each submitted NDA before it determines whether to file it, based on the agency’s threshold determination that it is sufficiently complete to permit substantive review, and FDA may request additional information. The FDA must make a decision on whether to file an NDA within 60 days of receipt, and such decision could include a refusal to file by the FDA. Once the submission is filed, FDA begins an in-depth review of the NDA. FDA has agreed to certain performance goals in the review of NDAs. FDA has set a performance goal for reviewing standard applications as within ten months of acceptance of an NDA for filing; and for priority review drugs, within six months of acceptance of an NDA for filing. Drugs may qualify for priority review if they would be a significant improvement in the safety or effectiveness of the treatment, diagnosis, or prevention of a serious condition. The review process for both standard and priority review may be extended by 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 NDAs, and the review process can be extended by FDA requests for additional information or clarification.

FDA may also refer applications for novel drug products, or drug 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. FDA is not bound by the recommendation of an advisory committee, but it generally follows such recommendations.

Before approving an NDA, FDA will conduct a pre-approval inspection (either in person or remotely) of the manufacturing facilities for the new product to determine whether they comply with cGMP requirements. 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 will not approve the product unless cGMP compliance is satisfactory. The FDA also typically inspects (either in person or remotely)

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one or more clinical trial sites to ensure compliance with GCP requirements and the integrity of the data supporting safety and efficacy.

After FDA evaluates the NDA and the manufacturing facilities, it issues either an approval letter or a complete response letter. A complete response letter, or CRL, generally outlines the deficiencies in the submission and may require substantial additional testing, or information, in order for 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. In 2025, FDA started publicly releasing complete response letters after issuance, for both products that eventually obtained approval and products that have not yet received approval. If a CRL is issued, the applicant may resubmit the NDA addressing all of the deficiencies identified in the letter, withdraw the application, engage in formal dispute resolution or request an opportunity for a hearing. FDA has committed to reviewing 90% of 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 the NDA does not satisfy the criteria for approval.

If, or when, the deficiencies identified in the CRL have been addressed to FDA’s satisfaction in a resubmission of the NDA, FDA will issue an approval letter. An approval letter authorizes commercial marketing of the drug with specific prescribing information for specific indications. As a condition of NDA approval, FDA may require a risk evaluation and mitigation strategy, or REMS, to help ensure that the benefits of the drug outweigh the potential risks to patients. A REMS can include medication guides, communication plans for healthcare professionals, and elements to assure safe use, or ETASU. ETASU can include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring, and the use of patient registries. The requirement for a REMS can materially affect the potential market and profitability of the drug. Moreover, product approval may require substantial post-approval testing and surveillance to monitor the drug’s safety or efficacy. Once granted, product approvals may be withdrawn if compliance with regulatory standards is not maintained or problems are identified following initial marketing.

There is no guarantee that FDA will approve an NDA. Moreover, even if marketing authorization of a product candidate is granted, the approval may be subject to limitations on the indicated uses for which the product may be marketed, the product may have labeling that includes significant restrictions, warnings, including black box warnings, and contraindications, the regulatory authorities may not approve label claims necessary for successful product marketing, or the approval may be subject to significant conditions of approval, including the requirement of a REMS.

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 supplement or, in some instances, a new NDA, before the change can be implemented. An NDA supplement for a new indication typically requires clinical data similar to that in the original application, and FDA uses the same procedures and actions in reviewing NDA supplements as it does in reviewing NDAs.

Disclosure of Clinical Trial Information

Sponsors of clinical trials of FDA regulated products, including drugs, are required to register and disclose certain clinical trial information. Information related to the product, patient population, phase of investigation, study sites and investigators, and other aspects of the clinical trial is then made public as part of the registration. Sponsors are also obligated to discuss the results of their clinical trials after completion. Disclosure of the results of these trials can be delayed in certain circumstances for up to two years after the date of completion of the trial, provided that certain criteria are met and certifications are provided. Competitors may use this publicly available information to gain knowledge regarding the progress of development programs. Failure to follow the applicable disclosure requirements can result in notices of noncompliance and civil monetary penalties.

Expedited Development and Review Programs

Fast Track Designation

Fast track designation may be granted for a product that is intended to treat a serious or life-threatening disease or condition for which preclinical or clinical data demonstrate the potential to address unmet medical needs for the condition. The sponsor of an investigational drug product may request that FDA designate the product candidate for a specific indication as a fast-track drug concurrent with, or after, the submission of the IND for the product candidate. FDA must determine if the product 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 potentially initiate review of

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sections of a fast track product’s NDA before the application is complete, referred to as “rolling review.” The sponsor must provide, and the FDA must approve, a schedule for the submission of the application and the sponsor must pay applicable user fees. The FDA may, however, not review applications submitted via rolling review until all sections of the application have been submitted. At the time of NDA filing, the FDA will determine whether to grant priority review designation. FDA will grant such designation if the proposed drug would be a significant improvement in the safety or effectiveness of the treatment, prevention, or diagnosis of a serious condition. Additionally, fast track designation may be withdrawn if FDA believes that the designation is no longer supported by data emerging in the clinical trial process.

Accelerated Approval

Accelerated approval may be granted for a product that is intended to treat a serious or life-threatening condition and that generally provides 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. 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. By the date of approval of an accelerated approval product, FDA must specify the conditions for the required post approval studies, including enrollment targets, the study protocol, milestones, and target completion dates. FDA may also, and frequently does, require that the confirmatory Phase 4 studies be commenced prior to FDA granting a product accelerated approval. Reports on the progress of the required Phase 4 confirmatory studies must be submitted to FDA every 180 days after approval. If the trials fail to verify the clinical benefit of the drug or biologics product, the FDA may withdraw approval of the application through a statutorily defined streamlined process. Failure to conduct the required Phase 4 confirmatory studies or to conduct such studies with due diligence, as well as failure to submit the required update reports can subject a sponsor to penalties. All promotional materials for product candidates approved under accelerated regulations are subject to prior review by the FDA.

Breakthrough Therapy Designation

FDA is also required to expedite the development and review of applications for approval of drugs that are intended to treat a serious or life-threatening disease or condition where preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints. Under the breakthrough therapy program, the sponsor of a new product candidate may request that FDA designate the product candidate for a specific indication as a breakthrough therapy concurrent with, or after, the filing of the IND for the product candidate. FDA must determine if the product candidate qualifies for a 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 but not limited to 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, granting priority review status or Fast Track Designation, reviewing applications on a rolling basis, and taking other steps to design the clinical studies in an efficient manner. FDA may withdraw breakthrough therapy designation if the conditions of the designation are no longer met.

Orphan Drugs

Under the Orphan Drug Act, 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. Additionally, to obtain orphan designation, sponsors must present a medically plausible basis for the use of the drug for the rare disease or condition and, if a product is already approved by the FDA that is considered by the FDA to be the same as

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the already approved product and is intended for the same indication, a plausible hypothesis for clinical superiority. This hypothesis must be demonstrated to obtain orphan exclusivity.

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

The first NDA applicant to receive FDA approval for a particular active moiety to treat a rare disease for which it has such designation is entitled to a seven-year exclusive marketing period in the U.S. for that product, for that indication for which it is approved. During the seven-year exclusivity period, 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 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.

Pediatric Information

Under the Pediatric Research Equity Act, or PREA, NDAs or supplements to NDAs must contain data to assess the safety and effectiveness of the drug for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the drug is safe and effective. FDA may grant full or partial waivers, or deferrals, for submission of data. Unless otherwise required by regulation, PREA does not apply to any drug for an indication for which orphan designation has been granted. However, compliance may be required if approval is sought for other indications for which the product has not received orphan designation.

Alternatively, product candidates intended for the treatment of adult cancer which are directed at molecular targets that the FDA determines to be substantially relevant to the growth or progression of pediatric cancer, must submit, with the marketing application, reports from molecularly targeted pediatric cancer investigations designed to yield clinically meaningful pediatric study data, gathered using appropriate formulations for each applicable age group, to inform potential pediatric labeling. The FDA may, on its own initiative or at the request of the applicant, grant deferrals or waivers of some or all of this data, as above. Orphan products are not exempt from this requirement.

The Best Pharmaceuticals for Children Act, or BPCA, provides NDA holders a six-month extension of any exclusivity—patent or nonpatent—for a drug if certain conditions are met. Conditions for exclusivity include FDA’s determination that information relating to the use of a new drug in the pediatric population may produce health benefits in that population, 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 is approved, a product will be subject to certain post-approval requirements. For instance, FDA closely regulates the post-approval marketing and promotion of drugs, including standards and regulations for direct-to-consumer advertising, off-label promotion, industry-sponsored scientific and educational activities and promotional activities involving the internet. Drugs may be marketed only for the approved indications and in a manner consistent with the approved labeling. Promotion and advertising must also be truthful and non-misleading, must be adequately substantiated, and with a fair balance between product benefit claims and risks, among other requirements. Over the last few years, FDA has taken a number of actions in the advertising and promotional spaces, including issuing a final rule and a guidance on risk and efficacy disclosures in direct-to-consumer advertising. In 2024, FDA also issued a final guidance on communication of off-label scientific information about approved products. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses. In fact, in 2025, FDA increased its enforcement activity regarding promotion and advertising, both in the areas of promotional statements to healthcare providers and direct to consumer advertising. Failure to comply with the laws and regulations governing advertising and promotion can have negative consequences, including FDA and other governmental authority enforcement actions.

Adverse event reporting and submission of periodic reports are required following FDA approval of an NDA. FDA also may require post-marketing testing, known as Phase 4 testing, REMS, and surveillance to monitor the effects of an approved product, or FDA may place conditions on an approval that could restrict the distribution or use of the product. In addition,

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quality control, drug manufacture, packaging and labeling procedures must continue to conform to cGMPs after approval. Drug manufacturers and certain of their subcontractors are required to register their establishments with FDA and certain state agencies and list the drugs produced. The information that must be submitted to FDA regarding manufactured products was expanded through the Coronavirus Aid, Relief, and Economic Security, or CARES Act to include the volume of drugs produced during the prior year. Registration with FDA subjects entities to periodic unannounced inspections or remote regulatory assessments by FDA, during which the Agency inspects or assesses manufacturing facilities to assess compliance with cGMPs. Accordingly, manufacturers must continue to expend time, money, and effort in the areas of production and quality-control to maintain compliance with cGMPs. 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. Sponsors are further subject to various requirements related to FDA drug shortage and manufacturing volume reporting, supply chain security, such as risk management plan requirements, and the promotion of supply chain redundancy. Legislation and executive actions have also been issued to encourage domestic manufacturing, as well as to decrease drug prices. For instance, FDA approved a plan that was submitted by Florida to import drugs from Canada. Executive orders have also been issued to facilitate and streamline the development of U.S. manufacturing, enhance the inspection of foreign manufacturing facilities, and potentially to increase foreign manufacturing facility user fees.

Changes to the product manufacturing process often require prior FDA approval or notification before being implemented. FDA regulations also require the investigation and correction of any identified deviations from cGMP and specifications, and impose reporting and documentation requirements upon the sponsor and any third-party manufacturers.

The Hatch-Waxman Amendments

Orange Book Listing

Under the Drug Price Competition and Patent Term Restoration Act of 1984, commonly referred to as the Hatch Waxman Amendments, NDA applicants are required to identify to FDA each patent whose claims cover the applicant’s drug or approved method of using the drug. Upon approval of a drug, the applicant must update its listing of patents to the NDA in timely fashion and each of the patents listed in the application for the drug is then published in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, commonly known as the Orange Book. In an effort to clarify which patents must be listed in the Orange Book, in January 2021, Congress passed the Orange Book Transparency Act of 2020, which largely codifies FDA’s existing practices into the FD&C Act. Listing patents in the Orange Book that do not qualify for listing can be considered to be anticompetitive conduct and subject to regulatory scrutiny and challenges. The Federal Trade Commission, or FTC, has sent letters to a number of companies with respect to certain patents that agency asserted were improperly listed or inaccurate. The FTC has signaled an increased focus on scrutinizing Orange Book listings as part of its broader efforts to combat practices that may delay generic and biosimilar competition. Listing these unqualified patents (e.g., patents covering unapproved formulations or non-drug product aspects) in the Orange Book has also been the subject of litigation.

Drugs listed in the Orange Book can, in turn, be cited by potential generic competitors in support of approval of an abbreviated new drug application, or ANDA or a 505(b)(2) NDA. An ANDA provides for marketing of a drug product that has the same active ingredient(s), strength, route of administration, and dosage form as the listed drug and has been shown through bioequivalence testing to be therapeutically equivalent to the listed drug. An approved ANDA product is considered to be therapeutically equivalent to the listed drug. Other than the requirement for bioequivalence testing, ANDA applicants are not required to conduct, or submit results of, pre-clinical or clinical tests to prove the safety or effectiveness of their drug product. Drugs approved under the ANDA pathway are commonly referred to as “generic equivalents” to the listed drug and can often be substituted by pharmacists under prescriptions written for the original listed drug pursuant to each state’s laws on drug substitution. 505(b)(2) NDAs are applications that contains full reports of investigations of safety and efficacy but where at least some of the information required for approval comes from investigations that were not conducted by or for the applicant and for which the applicant has not obtained the right of reference or use, and allows the 505(b)(2) applicant to rely, in part, on the FDA’s prior findings of safety and efficacy for an existing product, or published literature.

The ANDA or 505(b)(2) NDA applicant is required to certify to the FDA concerning any patents identified for the reference listed drug in the Orange Book. Specifically, the applicant must certify to each patent in one of the following ways: (i) the required patent information has not been filed; (ii) the listed patent has expired; (iii) the listed patent has not expired but will expire on a particular date and approval is sought after patent expiration; or (iv) the listed patent is invalid or will not be infringed by the new product. A certification that the new product will not infringe the already approved product’s listed

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patents, or that such patents are invalid, is called a Paragraph IV certification. For patents listed that claim an approved method of use, under certain circumstances the applicant may also elect to submit a section viii statement certifying that its proposed label does not contain (or carves out) any language regarding the patented method-of-use rather than certify to a listed method-of-use patent. If the applicant does not challenge the listed patents through a Paragraph IV certification, the application will not be approved until all the listed patents claiming the referenced product have expired. If the applicant has provided a Paragraph IV certification to the FDA, the applicant must also send notice of the Paragraph IV certification to the NDA-holder and patentee(s) within certain specified timeframes (referred to as the “notice letter”). The NDA and patent holders may then initiate a patent infringement lawsuit in response to the notice letter. The filing of a patent infringement lawsuit within 45 days of the receipt of a Paragraph IV certification automatically prevents the FDA from approving the ANDA or 505(b)(2) application until the earlier of 30 months from the date the notice letter is received, expiration of the patent, the date of a settlement order or consent decree signed and entered by the court stating that the patent that is the subject of the certification is invalid or not infringed, a decision in the patent case that is favorable to the ANDA or 505(b)(2) NDA applicant, or such shorter or longer period as may be ordered by a court.

The ANDA or 505(b)(2) application also will not be approved until any applicable non-patent exclusivity listed in the Orange Book for the referenced product has expired. In some instances, an applicant may receive approval prior to expiration of certain non-patent exclusivity if the applicant seeks, and FDA permits, the omission of such exclusivity-protected information from the prescribing information.

Exclusivity

Upon NDA approval of a new chemical entity, or NCE, which is a drug that contains no active moiety that has been approved by FDA in any other NDA, that drug receives five years of marketing exclusivity during which FDA cannot receive any ANDA or 505(b)(2) application seeking approval of a version of that drug unless the application contains a Paragraph IV certification, in which case the application may be submitted one year prior to expiration of the NCE exclusivity. If there is no listed patent in the Orange Book, there may not be a Paragraph IV certification, and, thus, no ANDA for a generic version of the drug or 505(b)(2) application relying on such drug may be filed before the expiration of the exclusivity period.

Certain changes to an approved drug, such as the approval of a new indication, the approval of a new strength, and the approval of a new condition of use, are associated with a three-year period of exclusivity from the date of approval during which FDA cannot approve an ANDA or 505(b)(2) application for a drug that includes the change. To qualify for three-year exclusivity, there must be new clinical investigations, other than bioavailability studies, supporting the application, that were conducted or sponsored by the applicant, and are deemed by the FDA to be essential to the approval of the application. In some instances, an applicant may receive approval prior to expiration of the three-year exclusivity if the applicant seeks, and FDA permits, the omission of such exclusivity-protected information from the package insert.

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, only applies to one patent per approved product and cannot extend the total term of a patent beyond 14 years from the product’s approval date. After NDA approval, owners of relevant drug patents may apply for the extension. The allowable patent term extension is calculated by taking into account (i) half of the drug’s testing phase (the time between IND application and NDA submission) and (ii) all of the review phase (the time between the full NDA submission and approval), up to a maximum of five years. The time can be reduced for any time the FDA determines the applicant did not pursue approval with due diligence.

The United States Patent and Trademark Office, or USPTO, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. The FDA provides a factual assessment of regulatory delay, while the USPTO makes the final determination regarding eligibility and the length of the extension. However, the USPTO may deny an application for 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 application for the extension must be submitted prior to the expiration of the patent. If a patent is set to expire while a patent term extension application is still under review, the patent owner may request an interim extension, which

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extends the term by one year per request, up to a maximum of four years. For each interim patent extension granted, the post-approval patent extension is reduced by an equal duration (e.g., one year per interim patent extension). 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. Interim patent extensions are not available for a drug for which an NDA has not been submitted.

FDA Regulation of Companion Diagnostics

If use of an in vitro diagnostic is essential to safe and effective use of a drug product, then the FDA generally will require approval or clearance of the diagnostic, known as a companion diagnostic, at the same time that the FDA approves the drug product. FDA has generally required manufacturers of in vitro companion diagnostics intended to select the patients who will respond to cancer treatment to submit a pre-market approval application, or PMA, for that diagnostic device simultaneously with the submission of the drug approval application by the drug manufacturer (which may be the same company as the device manufacturer or a different company). The review of these in vitro companion diagnostics in conjunction with the review of a cancer therapeutic involves coordination of review by the FDA’s Center for Drug Evaluation and Research and by the FDA’s Center for Devices and Radiological Health. Approval and clearance of a companion diagnostic also requires a high level of coordination between the drug manufacturer and device manufacturer, if different companies. In some cases, FDA may permit the use of a Laboratory Developed Test (LDT) as a companion diagnostic device. In general, tests that meet the definition of an LDT are not subject to FDA oversight and are not required to comply with FDA’s medical device regulatory requirements, including PMA approval requirements. However, LDTs must be developed, manufactured, and used in a single clinical laboratory location that has been certified under the Clinical Laboratory Improvement Amendments (CLIA). The laboratory also must be compliant with the CLIA regulations issued by the Centers for Medicare and Medicaid Services (CMS).

For those companion diagnostics that are not LDTs, the PMA process, including the gathering of extensive clinical and preclinical data and device manufacturing information, as well as the submission to and review by the FDA, can take several years or longer. It involves a rigorous premarket review during which the applicant must prepare and provide the FDA with test data and other information to demonstrate reasonable assurance of the device’s safety and effectiveness for its intended use, along with information about the device and its components regarding, among other things, device design, manufacturing and labeling. PMA applications are subject to a substantial application fee, which is typically increased annually.

In addition, PMAs must generally include the results from extensive preclinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for each indication for which FDA approval is sought. In particular, for a diagnostic, the applicant must demonstrate that the diagnostic has adequate sensitivity and specificity, has adequate specimen and reagent stability, and produces reproducible results when the same sample is tested multiple times by multiple users at multiple laboratories. As part of the PMA review, the FDA will inspect the manufacturer’s facilities for compliance with the Quality Management System Regulation, or QMSR, which imposes good manufacturing practice requirements for medical devices, including requirements for established processes, controls, recordkeeping, reporting, documentation and other quality assurance activities.

PMA approval is not guaranteed, and the FDA may ultimately respond to a PMA submission with a not approvable determination based on deficiencies in the application and require additional clinical trial or other data that may be expensive and time-consuming to generate and that can substantially delay approval. If the FDA’s evaluation of the PMA application is favorable, the FDA typically issues an approvable letter requiring the applicant’s agreement to specific conditions, such as changes in labeling, or submission of specific additional information, such as submission of final labeling, in order to secure final approval of the PMA. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the approved indications, which can be more limited than those originally sought by the applicant. The PMA can include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, restrictions on labeling, promotion, sale and distribution.

After a device is placed on the market, it remains subject to significant regulatory requirements. Medical devices may be marketed only for the uses and indications for which they are cleared or approved. Device manufacturers must also register each of their establishment(s) engaged in design, manufacturing or initial importation activities, including payment of an annual establishment registration fee, and list the device(s) at each such establishment with the FDA. A medical device manufacturer’s design and manufacturing processes and those of its contract manufacturers are required to comply with the applicable portions of the QMSR, which cover the methods and documentation of the design, testing, production, processes, controls, quality assurance, labeling, packaging and shipping of medical devices. Device manufacturers also have post-market reporting requirements for certain types of adverse events and device malfunctions, as well as for device correction

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and removal activities (including recalls). Domestic facility records and manufacturing processes are subject to periodic unscheduled inspections by the FDA. The FDA also may inspect foreign facilities that export products to the United States.

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, false claims, transparency and health information privacy laws and other healthcare laws and regulations.

The federal Anti-Kickback Statute is a criminal statute that 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. The term “remuneration” has been interpreted broadly to include anything of value. Several courts have interpreted the statute’s intent requirement to mean that if any one purpose of an arrangement involving remuneration is to induce or reward referrals of federal healthcare program business, including purchases of products paid by federal healthcare programs, the statute has been violated. The Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, collectively, the ACA, amended the intent element of the federal statute so that a person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it in order to commit a violation. 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 drawn narrowly, and practices that involve remuneration that may be alleged to be intended to induce prescribing, purchases or recommendations may be subject to scrutiny and enforcement action if they do not qualify for an exception or safe harbor. Failure to meet all of the requirements of a particular applicable statutory exception or regulatory safe harbor does not make the conduct per se illegal under the Anti-Kickback Statute. Instead, the legality of the arrangement will be evaluated on a case-by-case basis based on a cumulative review of all of the facts and circumstances. Additionally, the ACA amended the federal Anti-Kickback Statute such that a violation of that statute is a per se violation of the federal civil False Claims Act. The Beneficiary Inducement Civil Monetary Penalties Law imposes similar restrictions on interactions between the biopharmaceutical industry and federal healthcare program beneficiaries.

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, using, or causing to be made or used, a false statement to have a false claim paid, or avoiding, decreasing or concealing an obligation to pay money to the federal government. Intent to deceive is not required to establish liability under the civil False Claims Act. Rather, a claim may be false for deliberate ignorance of the truth or falsity of the information provided or for acts in reckless disregard of the truth or falsity of that information. Civil False Claims Act actions may be brought by the government or may be brought by private individuals on behalf of the government, called “qui tam” actions. If the government decides to intervene in a qui tam action and prevails in the lawsuit, the individual will share in the proceeds from any damages, penalties or settlement funds. If the government declines to intervene, the individual may pursue the case alone if it is not also dismissed by the government. The civil False Claims Act provides for treble damages and a civil penalty for each false claim, such as an invoice or pharmacy claim for reimbursement, which can aggregate into tens and even hundreds of millions of dollars. For these reasons, since 2004, False Claims Act lawsuits against biopharmaceutical companies have increased significantly in volume and breadth, leading to several substantial global civil and criminal settlements of as much as $3.0 billion regarding certain sales and promotional practices.

The civil False Claims Act has been used to assert liability on the basis of 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. Pharmaceutical and other healthcare companies have been prosecuted under these laws for, among other things, 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 rebates, 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. Private payers have been filing follow-on lawsuits alleging fraudulent misrepresentation, although establishing liability and damages in these cases is more difficult than under the 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.

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The government may further prosecute conduct constituting a false claim under the criminal False Claims Act. The criminal False Claims Act prohibits the making or presenting of a claim to the government knowing such claim to be false, fictitious or fraudulent. Unlike the civil False Claims Act, the criminal False Claims Act requires proof of intent to submit a false claim.

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 or 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, or HIPAA, which prohibit, among other things, knowingly and willfully executing or attempting to execute a scheme to defraud any healthcare benefit program, regardless of whether the payor is public or private, 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.

In addition, we may be subject to healthcare data privacy and security regulations promulgated by both the federal government and the states in which we conduct our business. HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, (“HITECH Act”), and their respective implementing regulations, impose certain requirements on covered entities relating to the privacy, security, and transmission of certain individually identifiable health information known as protected health information. The HIPAA privacy regulations impose certain requirements with respect to the disclosure of protected health information for research purposes, such as clinical trials. Among other things, the HITECH Act and its implementing regulations, made HIPAA’s security standards and certain privacy standards directly applicable to business associates, who, on behalf of covered entities, other than members of a covered entity’s workforce, create, receive, maintain or transmit protected health information for a function or activity regulated by HIPAA. The HITECH Act also strengthened the civil and criminal sanctions that may be imposed against covered entities, business associates, and individuals, and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts to enforce the federal HIPAA laws and seek attorneys’ fees and costs associated with pursuing federal civil actions. Other federal and state laws, such as the California Consumer Privacy Act (“CCPA”) and Washington’s My Health My Data Act, may govern the privacy and security of health and other information in certain circumstances, many of which differ from each other in significant ways and may not be preempted by HIPAA, thus complicating compliance efforts. Since the CCPA was signed into law in 2018, numerous other states, including Virginia, Colorado, Utah and Connecticut, have enacted similar privacy laws that may apply to personal information that we collect or maintain.

Further, pursuant to the ACA, the Centers for Medicare & Medicaid Services, or CMS, issued a final rule implementing the federal Physician Payment Sunshine Act that requires certain manufacturers of prescription drugs, medical devices and medical products to collect and annually report information on certain payments or transfers of value to U.S.-licensed physicians, as defined by such law, and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members. The reported data is made available in searchable form on a public website on an annual basis. Failure to submit timely, accurate and complete required information may result in civil monetary penalties. Beginning calendar year 2021, manufacturers must also collect information regarding payments and other transfers of value to physician assistants, nurse practitioners, clinical nurse specialists, certified registered nurse anesthetists and anesthesiologist assistants, and certified nurse- midwives for reporting in 2022.

In addition, several states now require prescription drug companies to report certain expenses relating to the marketing and promotion of drug products, to report gifts and payments to individual healthcare practitioners, to prohibit various marketing-related activities, such as the provision of certain kinds of gifts or meals, and/or to comply with certain compliance requirements.

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. Several additional states are considering similar proposals. Certain states and local jurisdictions also require the registration of pharmaceutical sales representatives. Compliance with these laws is difficult and time consuming, and companies that do not comply with these state laws face civil penalties. Additionally, we may also be subject to state and foreign laws governing the privacy and security of health information in some circumstances, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

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 sanctions, including civil and administrative penalties and damages, criminal fines and confinement, disgorgement, the curtailment or restructuring of its operations, loss of eligibility to obtain approvals from the FDA,

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exclusion from participation in federal health care programs, suspension and debarment from government procurement and non-procurement programs, refusal of orders under existing government contracts, integrity oversight and reporting obligations, and reputational harm. Although effective compliance programs can mitigate the risk of investigation and enforcement actions 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, which was intended to broaden access to health insurance, reduce or constrain the growth of healthcare spending, enhance remedies against fraud and abuse, add new transparency requirements for the healthcare and health insurance industries, impose new taxes and fees on the health industry and impose additional health policy reforms. The ACA substantially changed the way healthcare is financed by both governmental and private insurers, and significantly impacts the U.S. pharmaceutical industry. The ACA, among other things, (i) subjected therapeutic biologics to potential competition by lower-cost biosimilars by creating a licensure framework for follow-on biologic products, (ii) proscribed a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for drugs and therapeutic biologics that are inhaled, infused, instilled, implanted or injected, (iii) increased the minimum Medicaid rebates owed by manufacturers under the Medicaid Drug Rebate Program and extended the rebate program to individuals enrolled in Medicaid managed care organizations, (iv) established annual nondeductible fees and taxes on manufacturers of certain branded prescription drugs and therapeutic biologics, apportioned among these entities according to their market share in certain government healthcare programs, (v) expanded eligibility criteria for Medicaid programs by, among other things, allowing states to offer Medicaid coverage to additional individuals and by adding new mandatory eligibility categories for individuals with income at or below 133% of the federal poverty level, thereby potentially increasing manufacturers’ Medicaid rebate liability, (vi) expanded the entities eligible for discounts under the Public Health program, (vii) created a new Patient-Centered Outcomes Research Institute to oversee, identify priorities in, and conduct comparative clinical effectiveness research, along with funding for such research, and (viii) established a Center for Medicare and Medicaid Innovation at CMS to test innovative payment and service delivery models to lower Medicare and Medicaid spending, potentially including prescription drug spending. There have been legislative and judicial efforts to modify, repeal, or otherwise invalidate all, or certain provisions of, the ACA. We cannot predict the ultimate content, timing or effect of any healthcare reform legislation or the impact of potential legislation on us.

Other legislative changes have been proposed and adopted in the United States since the ACA was enacted to reduce healthcare expenditures. United States federal government agencies also currently face potentially significant spending reductions, which may further impact healthcare expenditures. On August 2, 2011, the Budget Control Act of 2011 among other things, created measures for spending reductions by Congress. A Joint Select Committee on Deficit Reduction, tasked with recommending a targeted deficit reduction of at least $1.2 trillion for the years 2012 through 2021, was unable to reach required goals, thereby triggering the legislation’s automatic reduction to several government programs. This includes aggregate reductions of Medicare payments to providers of 2% per fiscal year. These reductions went into effect on April 1, 2013 and, due to subsequent legislative amendments to the statute, including the BBA, regardless of whether the payor is public or private, will remain in effect through 2032 unless additional Congressional action is taken. Moreover, on January 2, 2013, the American Taxpayer Relief Act of 2012 was signed into law, which, among other things, further reduced Medicare payments to several types of providers, including hospitals, imaging centers and cancer treatment centers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years. If federal spending is further reduced, anticipated budgetary shortfalls may also impact the ability of relevant agencies, such as the FDA or the National Institutes of Health to continue to function at current levels. Amounts allocated to federal grants and contracts may be (and have been) reduced or eliminated. These reductions may also impact the ability of relevant agencies to timely review and approve research and development, manufacturing, and marketing activities, which may delay our ability to develop, market and sell any products we may develop.

Recently, there has been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing and price increases, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products.

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The Trump and Biden administrations both issued executive orders intended to favor and encourage domestic manufacturing. And on August 16, 2022, former President Biden signed into the law the Inflation Reduction Act of 2022, or the IRA. Among other things, the IRA has multiple provisions that may impact the prices of drug products, such as negotiated ceiling prices and penalties for price increases that exceed the rate of inflation that are sold into the Medicare program. Drug price negotiations and other IRA program implementation measures could potentially be affected by the changes in leadership at Health and Human Services (HHS) and the Centers for Medicare and Medicaid Services (CMS) under the new administration.

Further, on November 20, 2020, HHS finalized a regulation removing safe harbor protection for price reductions from pharmaceutical manufacturers to plan sponsors under Part D, either directly or through pharmacy benefit managers, unless the price reduction is required by law. The rule also creates a new safe harbor for price reductions reflected at the point-of-sale, as well as a safe harbor for certain fixed fee arrangements between pharmacy benefit managers and manufacturers. Recent legislation has delayed implementation of the aforementioned regulation until January 1, 2032. CMS also published an interim final rule that establishes an MFN Model under which reimbursement for certain Medicare Part B drugs and biologicals would be based on a price that reflects the lowest per capita Gross Domestic Product-adjusted (GDP-adjusted) price of any non-U.S. member country of the Organization for Economic Co-operation and Development (OECD) with a GDP per capita that is at least sixty percent of the U.S. GDP per capita. While this rule now has been rescinded, in November 2025, CMS introduced the GENEROUS Model (launching 2026), which requires manufacturers to provide rebates aligned with most favored nation pricing to participating state Medicaid programs that opt into the 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 reimbursement constraints or caps, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, to encourage importation from other countries and bulk purchasing. States, such as Maryland, have also established Drug Affordability Review Boards for the purpose of establishing upper payment limits for certain high-cost drugs which could result in reduced reimbursement for those products.

Coverage and Reimbursement

Patients in the United States and elsewhere generally rely on third-party payors to reimburse part or all of the costs associated with their prescription drugs. Accordingly, market acceptance of our drug products is dependent on the extent to which third-party coverage and reimbursement is available from government health administration authorities (including in connection with government healthcare programs, such as Medicare and Medicaid in the United States), private healthcare insurers and other healthcare funding organizations. Significant uncertainty exists as to the coverage and reimbursement status of any drug products for which we may obtain regulatory approval. Coverage decisions may not favor new drug products when more established or lower-cost therapeutic alternatives are already available. Patients are unlikely to use our products unless reimbursement is adequate to cover all or a significant portion of the cost of our drug products.

Coverage and reimbursement policies for drug products can differ significantly from payor to payor as there is no uniform policy of coverage and reimbursement for drug products among third-party payors in the United States, although private payors often, but not always, follow CMS’s decisions regarding coverage and reimbursement. There may be significant delays in obtaining coverage and reimbursement as the process of determining coverage and reimbursement is often time-consuming and costly which will require us to provide scientific and clinical support for the use of our products to each payor separately, with no assurance that coverage or adequate reimbursement will be obtained. It is difficult to predict at this time what government authorities and third-party payors will decide with respect to coverage and reimbursement for our drug products. Additionally, we may develop, either by ourselves or with collaborators, companion diagnostic tests for our product candidates for certain indications. We, or our collaborators, if any, will be required to obtain coverage and reimbursement for these tests separate and apart from the coverage and reimbursement we seek for our product candidates, once approved.

The market for our product candidates will depend significantly on access to third-party payors’ drug formularies or lists of medications for which third-party payors provide coverage and reimbursement. Competition to be included in such formularies often leads to downward pricing pressures. In particular, third-party payors may refuse to include a particular reference listed drug in their formularies or otherwise restrict patient access to a reference listed drug when a less costly generic equivalent or other alternative is available. Third-party payors may require prior authorizations or failure on another type of treatment before covering a particular drug, particularly with respect to higher-priced drugs. Decreases in third-party reimbursement for a product or a decision by a third-party payor to not cover a product could reduce physician usage of the

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product. If these products do not achieve an adequate level of acceptance, we may not generate significant product revenues or any profits from operations.

The U.S. government, state legislatures and foreign governmental entities have shown significant interest in implementing cost containment programs to limit the growth of government-paid healthcare costs, including price controls, restrictions on reimbursement and coverage and requirements for substitution of generic products for branded prescription drugs. Adoption of government controls and measures and tightening of restrictive policies in jurisdictions with existing controls and measures could exclude or limit our drugs products from coverage and limit payments for pharmaceuticals.

In addition, we expect that the increased emphasis on managed care and cost containment measures in the United States by third-party payors and government authorities to continue, which will place pressure on pharmaceutical pricing and coverage. 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 drug products for which we receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

Employees

As of December 31, 2025, we had 79 full-time employees. Of our employees, 53% have an M.D. or a Ph.D. From time to time, we also retain independent contractors to support our organization. None of our employees are represented by a labor union or covered by collective bargaining agreements, and we believe our relationship with our employees is good.

Corporate Information

We were incorporated under the laws of the State of Delaware in 2016. Our principal executive offices are located in Wilmington, DE. Our website address is www.preludetx.com. Website references in this Annual Report on Form 10-K are inactive, textual references only, and the information contained on, or that can be accessed through, our website is not part of, and is not incorporated by reference into, this Annual Report on Form 10-K.

The mark “Prelude Therapeutics,” the Prelude logo and all product names are our common law trademarks. All other service marks, trademarks and trade names appearing in this Annual Report on Form 10-K are the property of their respective owners. Solely for convenience, the trademarks and tradenames referred to in this Annual Report on Form 10-K appear without the ® and ™ symbols, but those references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights, or the right of the applicable licensor to these trademarks and tradenames.

Available Information

We file our annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, electronically with the U.S. Securities and Exchange Commission, or the SEC. The SEC maintains an Internet site that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC. The address of that site is http://www.sec.gov.

We make available free of charge electronic versions of our Annual Report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and amendments to those reports on our website, preludetx.com, as soon as reasonably practicable after we electronically file or furnish such materials to the Securities and Exchange Commission, or SEC.

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