Invivyd, Inc. (Nasdaq: IVVD) announced positive topline results from the LIBERTY Phase 3 study on September 29, 2026. The study evaluated the safety and tolerability of VYD2311, an investigational COVID-19 monoclonal antibody, compared to the mRNA-based COVID-19 vaccine COMIRNATY and a combination of both.

The LIBERTY study enrolled 210 healthy adults aged 18 to 49. Subjects were randomized 1:1:1 to receive a single intramuscular dose of either 250mg VYD2311, COMIRNATY, or the combination of VYD2311 and COMIRNATY. To maintain blinding, all subjects received two injections, with placebo injections volume-matched to either VYD2311 (2mL) or the vaccine (0.5mL).

The study met its co-primary endpoints, demonstrating that VYD2311 had a statistically superior safety and tolerability profile compared to the mRNA vaccine. Over the first six days following dosing, 56.5% of subjects in the VYD2311 arm experienced a treatment-emergent adverse event, injection site reaction, or hypersensitivity reaction, compared to 91.4% in the COMIRNATY arm (P < 0.0001). Similarly, systemic adverse events were reported by 44.1% of VYD2311 recipients versus 68.1% of vaccine recipients (P = 0.008). Over the full 56-day study period, VYD2311 showed a 60.9% rate of such events compared to 91.4% for the vaccine (P < 0.0001).

Invivyd also evaluated the combination of VYD2311 and the mRNA vaccine. The data indicate that the combination did not interfere with vaccine-induced neutralizing titers; instead, it increased neutralizing titers from the vaccine alone by approximately 2.5x over the 56-day study. The company noted that no adverse events related to VYD2311 exceeded Grade 2, and no hypersensitivity or anaphylaxis was observed.

Regarding regulatory plans, Invivyd intends to submit a Biologics License Application (BLA) for VYD2311 to the U.S. Food and Drug Administration via the Accelerated Approval Program following a recent Type C meeting. The company expects to receive placebo-controlled safety and immunogenicity data from the ongoing DECLARATION pivotal study in October. If Accelerated Approval is granted, Invivyd plans to unblind efficacy data from DECLARATION later, subject to clinical event accrual.