VYD2311 - (DECLARATION)

April 9, 2026: Invivyd, Inc. (NASDAQ: IVVD) provided a Phase 3 update for VYD2311, an investigational monoclonal antibody for pre-exposure prophylaxis of symptomatic COVID-19, and announced a new measles antibody candidate.

VYD2311 – Phase 3 DECLARATION (BLA-directed): In a pre-specified pooled, blinded sample-size re-estimation conducted when the first 1,500 of 1,818 enrolled participants reached Day 45 (April 6), accumulated COVID-19 events (~50% study progress) were stated to already support statistical power for the high end of anticipated efficacy; the conservative algorithm nevertheless triggered an upsizing. The trial will add ~500 subjects (on top of 1,818 randomized), and top-line results are now expected in Q3 2026, ~2 months later than prior “mid-year” 2026 guidance.

VYD2311 – Pediatrics (“DRUMMER”): Invivyd and FDA aligned on an initial Pediatric Study Plan for a BLA-directed pediatric immunobridging/safety trial in ages 0–11, to be initiated only if DECLARATION is successful.

Measles – VMS063 (new preclinical/IND-enabling): Invivyd advanced VMS063, a half-life-extended anti-measles F protein mAb with in vitro neutralization across lineages; IND-enablement and regulatory outreach have begun with target IND readiness in late 2026.