Invivyd completes enrolment in Phase 3 LIBERTY COVID antibody trial
Invivyd has completed enrolment in its Phase 3 LIBERTY clinical trial, which is comparing the safety, tolerability, and immune response of its investigational monoclonal antibody VYD2311 against an approved mRNA COVID-19 vaccine. The Connecticut-based biopharmaceutical company said it expects to report topline results in the third quarter of 2026, potentially alongside data from its larger, pivotal DECLARATION trial.
LIBERTY is a randomised, double-blind study involving approximately 210 healthy adults. Its primary endpoint focuses on side-effect profile and tolerability over the first seven days following administration, rather than efficacy against infection. The co-administration arm, in which participants receive both VYD2311 and an mRNA vaccine together, adds a further dimension that could inform future real-world use if the antibody reaches the market.
The case for an antibody alternative
The clinical rationale for the trial rests on a recognised gap in the COVID-19 prevention landscape. Chief Medical Officer Michael Mina noted that systemic side effects associated with mRNA vaccines, driven by the inflammatory response those products are designed to elicit, have on average persisted for around three days in recipients, and that concerns about these effects have contributed to reduced booster uptake in some populations. Invivyd is positioning VYD2311 as a candidate that may offer an improved tolerability profile and thus reach individuals who have declined or cannot tolerate vaccination.
VYD2311 is administered by intramuscular injection and was engineered using Invivyd's molecular evolution platform. It shares an antibody backbone with pemivibart, which received emergency use authorisation from the US FDA in March 2024 for pre-exposure prophylaxis of COVID-19 in certain immunocompromised patients. LIBERTY sits within the company's broader REVOLUTION clinical programme alongside DECLARATION, a roughly 2,400-participant randomised, triple-blind, placebo-controlled study evaluating single and monthly doses of VYD2311.
Market and regulatory context
The monoclonal antibody field for COVID-19 prevention has contracted sharply since the early pandemic years, with several authorisations withdrawn or not renewed as dominant viral lineages changed. Invivyd is one of the few remaining developers pursuing an antibody-based prophylaxis strategy for the broader population rather than solely for the immunocompromised. That commercial positioning is unusual but not unique: a small number of academic and industry groups continue to explore long-acting antibodies as a complement or substitute for vaccines, particularly for individuals with suboptimal vaccine responses.
Regulatory engagement will be central to the programme's prospects. The company has indicated ongoing dialogue with the FDA, and the results from both LIBERTY and DECLARATION will need to support a Biologics Licence Application submission. A tolerability advantage demonstrated in LIBERTY would strengthen the clinical narrative, but payers and regulators are likely to weigh efficacy data from DECLARATION more heavily when assessing the overall benefit-risk profile of VYD2311 relative to existing approved options.
The Q3 2026 topline readout timeline gives investors and the broader field a near-term catalyst. The scale of the LIBERTY study, at 210 participants, means the safety and tolerability dataset will carry inherent statistical limitations; the more consequential evidence is expected to come from DECLARATION. How clearly the two datasets tell a coherent story together will shape the regulatory and commercial path for VYD2311.