Assembly reports positive Phase 1b data; Gilead licenses herpes program for $35M, declines HBV

Filed March 19, 2026 · Period ending December 31, 2025 · Compared to 10-K Mar 20, 2025 · ~2 min read

Key Changes

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  Gilead exercised its option to license the HPI program (5366 and 1179) for $35M in December 2025, triggering the first major monetization under the collaboration. Assembly retains rights to opt into 40% U.S. profit-share or receive up to $330M in milestones plus royalties.

  MD&A: Gilead Collaboration verify on EDGAR →
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  Gilead declined its option on 4334 (HBV capsid assembly modulator) in March 2026. Assembly retains full control and initiated a structured partnering process; development will not proceed without a partner.

  MD&A: 4334 Partnering verify on EDGAR →
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  5366 and 1179 demonstrated exceptional Phase 1b results: 5366 achieved 94% reduction in HSV-2 shedding with weekly dosing (exceeding 80-85% target); 1179 achieved 98% reduction. Both candidates are ready for Phase 2.

  Business: HPI Phase 1b Results verify on EDGAR →