Agios Pharmaceuticals Inc. (NASDAQ: AGIO) submitted a supplemental new drug application to the U.S. Food and Drug Administration seeking accelerated approval of mitapivat for treating sickle cell disease, the company announced.

The submission follows an agreement with the FDA on a confirmatory clinical trial required under the accelerated approval pathway. The confirmatory trial will evaluate mitapivat's ability to reduce transfusion burden in sickle cell disease patients, with a primary endpoint of transfusion-free status from week 4 through week 52.

The global, randomized, double-blind, placebo-controlled trial will enroll approximately 159 patients aged 12 years or older with sickle cell disease over 52 weeks. The trial design incorporates findings from the RISE UP Phase 3 trial, which showed a reduction in transfusion burden with mitapivat compared to placebo.

The application is based on data from the RISE UP Phase 2 and Phase 3 trials. In the Phase 3 trial, mitapivat demonstrated statistically significant improvement in hemoglobin response compared to placebo, defined as a 1.0 g/dL or greater increase from baseline in average hemoglobin concentration from week 24 through week 52. The drug showed a reduction in annualized rate of sickle cell pain crises compared with placebo, though this endpoint did not reach statistical significance.

Agios expects to receive notice of the application's filing acceptance and anticipated review timeline in the third quarter of 2026, following the FDA's 60-day filing review period.

Mitapivat is an oral pyruvate kinase activator designed to enhance red blood cell energy production. The drug has received regulatory approvals for two other rare hemolytic anemias.