# Invivyd Begins Phase 2 Trial of VYD2311 for Long COVID and Post-Vaccination Syndrome

- URL: https://stocks.freetheai.org/news/invivyd-begins-phase-2-trial-of-vyd2311-for-long-covid-and-post-vaccination-0deae9
- Published: 2026-10-14T11:01:00Z
- Category: company_news; sentiment: neutral; impact: medium
- Symbols: [NASDAQ:IVVD](https://stocks.freetheai.org/symbols/NASDAQ-IVVD)
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Invivyd, Inc. (IVVD) has launched FLINTLOCK, a Phase 2 clinical study evaluating its investigational antibody VYD2311. The randomized, placebo-controlled trial plans to enroll approximately 130 adult participants suffering from Long COVID or Post-Vaccination Syndrome. Participants will receive an initial intravenous loading dose followed by intramuscular administration through day 60.

The trial represents a strategic expansion for Invivyd, moving its monoclonal antibody platform beyond pre-exposure prophylaxis into the treatment of post-acute conditions. VYD2311 shares the same structural backbone as pemivibart, allowing the company to build on existing safety and pharmacokinetic data. Demonstrating efficacy in this proof-of-concept study could help address significant unmet medical needs in post-acute care.

Investors will be watching for initial clinical safety and efficacy signals to determine whether the therapy can advance toward larger pivotal studies. Following the trial announcement, shares of Invivyd, Inc. traded down 4.05% at $0.646.

## Key points

- Invivyd, Inc. (IVVD) initiated FLINTLOCK, a Phase 2 trial evaluating VYD2311 in roughly 130 adults.
- The study focuses on treatment for Long COVID and Post-Vaccination Syndrome.
- Dosing includes an intravenous loading dose followed by intramuscular doses through day 60.
- VYD2311 shares the same structural backbone as pemivibart to leverage established safety data.

## Questions and answers

### What is the FLINTLOCK trial by Invivyd?

FLINTLOCK is a Phase 2 trial evaluating VYD2311 in about 130 adults with Long COVID or Post-Vaccination Syndrome using IV and IM dosing up to day 60.

### What drug candidate is Invivyd testing in Phase 2?

Invivyd is testing VYD2311, an antibody candidate that shares the same structural backbone as pemivibart.

### What conditions does VYD2311 target?

VYD2311 targets post-acute conditions, specifically Long COVID and Post-Vaccination Syndrome.