Invivyd and the SPEAR Study Group Announce Initiation of “FLINTLOCK” Phase 2 Study of VYD2311, a Monoclonal Antibody for the Potential Treatment of Long COVID or Post-Vaccination Syndrome
Key Highlights
- ➤FLINTLOCK Phase 2 trial initiated for VYD2311 in Long COVID and PVS adults
- ➤Approximately 130 participants will receive three VYD2311 doses over 90 days
- ➤Initial FLINTLOCK data expected in mid-2027
- ➤VYD2311 demonstrated in vitro antiviral potency across tested SARS-CoV-2 variants
Expert Statements
David Putrino, Ph.D., Nash Family Director of the Cohen Center for Recovery from Complex Chronic Illness at Mount Sinai and Founding Member of the SPEAR Study Group
“Long COVID continues to be a significant challenge for millions of Americans. It is a disease state characterized by persistent and debilitating symptoms impacting multiple systems across the human body, including immune dysfunction, cardiovascular issues, respiratory challenges, nervous system dysfunction, pain, and other health issues that can impact a person’s day-to-day life.”
David Putrino, Ph.D., Nash Family Director of the Cohen Center for Recovery from Complex Chronic Illness at Mount Sinai and Founding Member of the SPEAR Study Group
“We are excited to take the next step in advancing this potential therapeutic option for patients living with Long COVID or Post-Vaccination Syndrome, a diagnosis which has received very little attention.”
Marc Elia, Chairman and CEO of Invivyd
“Both Long COVID and COVID PVS may share the inflammatory presence of persistent SARS-CoV-2 spike protein in the underlying disease processes, and so we are bringing to bear our pharmacology that is specifically directed against the SARS-CoV-2 spike protein target in large quantities.”
Marc Elia, Chairman and CEO of Invivyd
“Previous Long COVID antiviral therapeutic efforts have been limited by use of short course therapies that may not adequately inhibit viral replication, or by the use of monoclonal antibody candidates that lacked activity against many known and circulating clinical variants.”
Marc Elia, Chairman and CEO of Invivyd
“However, given anecdotal independent case reports of highly active monoclonal antibodies generating clinical improvements in Long COVID patients, including with our current monoclonal antibody medicine PEMGARDA(®) (pemivibart), we are looking forward to advancing FLINTLOCK and potentially bringing forward a therapeutic option for the benefit of people suffering from Long COVID.”
* FLINTLOCK Phase 2 clinical trial will evaluate the safety, tolerability, pharmacokinetics, and clinical efficacy of high-dose monoclonal antibody VYD2311 in adults aged 18-65 years with Long COVID or Post-Vaccination Syndrome, also known as COVID vaccine injury * Design includes VYD2311 administered in three doses to assess the safety and potential clinical benefit of VYD2311 treatment versus placebo over 90 days * VYD2311 has demonstrated high in vitro antiviral potency across all SARS-CoV-2 variants tested from original Wuhan through contemporary Omicron variants * FLINTLOCK is part of Invivyd’s broader REVOLUTION clinical program for VYD2311, including DECLARATION and LIBERTY * Millions of individuals continue to live with persistent and debilitating symptoms of Long COVID, underscoring the significant unmet need for development of effective treatment options NEW HAVEN, Conn., Oct. 14, 2026 (GLOBE NEWSWIRE) -- Invivyd, Inc. (Nasdaq: IVVD) and the SPEAR Study Group today announced the initiation of FLINTLOCK, a Phase 2 clinical trial evaluating the safety, tolerability, pharmacokinetics, and clinical efficacy of high-dose monoclonal antibody VYD2311 in individuals with Long COVID or Post-Vaccination Syndrome (PVS), also known as COVID vaccine injury.
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