Invivyd Inc. (NASDAQ: IVVD) announced the publication of research comparing side effects between its investigational COVID-19 monoclonal antibody and vaccines. The study, published as a preprint on MedRxiv, analyzed tolerability data from the company's EVADE trial of adintrevimab, comparing it to vaccine data from Sanofi's COMPARE study.

The research showed significant differences in systemic adverse events within seven days of administration. According to the data, mRNA vaccines caused Grade 2/3 systemic adverse events in 91.6% of recipients, while protein vaccines affected 83.6%. In contrast, Invivyd's monoclonal antibody adintrevimab showed adverse events in 2% of recipients compared to 1% for placebo.

The COMPARE study, presented at the European Society of Clinical Microbiology and Infectious Diseases in April 2026, found that protein vaccines resulted in symptoms lasting 3.1 days on average, while mRNA vaccines caused symptoms for 3.5 days.

Adintrevimab serves as the parent antibody to Invivyd's current candidates pemivibart and VYD2311. The company received emergency use authorization from the FDA in March 2024 for pemivibart as a monoclonal antibody treatment.

Invivyd plans to initiate its LIBERTY Phase 3 study, which will directly compare VYD2311 against mRNA vaccines in a controlled trial. The study is expected to enroll approximately 210 participants and will evaluate safety, antibody responses, and pharmacokinetics.

The research represents a cross-trial comparison with methodological differences between the studies, as acknowledged by the company. VYD2311 is designed for intramuscular administration and was developed using Invivyd's antibody engineering platform.