On Aug. 13, 2021, Rigel Pharma announced that the U.S. Food and Drug Administration (FDA) had informed the Company that clinical data submitted in late-May from a 59-patient NIH/NHLBI-sponsored Phase 2 trial of fostamatinib to treat hospitalized patients suffering from COVID-19 are insufficient for an emergency use authorization (EUA) at this time.

The Company was concurrently conducting a larger Phase 3 clinical trial evaluating fostamatinib in hospitalized patients with COVID-19.