Sickle Cell Advocates Affirm Support for Drug Development Following the Discontinuation of Pfizer’s THRIVE-131 Trial

August 15, 2025

WASHINGTON, D.C. — Pfizer announced today that its Phase 3 Trial, THRIVE-131, evaluating Inclacumab – an investigational P-selectin inhibitor – for the reduction of vaso-occlusive crises (VOCs) in people with sickle cell disease (SCD) did not meet its primary endpoint and will be discontinued.

While this news is disappointing, it is not unusual for drug trials to end before reaching the market. In fact, more clinical trials are halted than completed and such decisions are part of the rigorous process designed to ensure that any treatment made available is shown to be safe and effective before reaching the public.

Clinical trials and innovation remain vital to improving the health and quality of life for people living with SCD. We remain committed to supporting clinical research, ensuring that the perspectives and needs of the SCD community are reflected in every step of the process.

We are deeply grateful to the participants of THRIVE-131, whose involvement strengthens the future of sickle cell treatments. We are encouraged by the continued momentum in drug development for SCD and will keep advocating for studies that place the needs of people with SCD at the center.

— Sick Cells, Sickle Cell Medical Advocacy Inc., Sickle Cell Foundation of Georgia, Inc., Sickle Cell Disease Association of America Inc. Crescent Foundation, SC RED, Sickle Cell 101, Sickle Cell Community Consortium

View the official statement here.