On Sept. 1, 2021, Rigel Pharma announced the publication of results from a Phase 2 clinical trial evaluating the safety of fostamatinib for treatment of hospitalized patients with COVID-19, in Clinical Infectious Diseases, an official publication of the Infectious Disease Society of America. The study was sponsored by the National Heart, Lung, and Blood Institute.

The results from the 59 patient Phase 2 trial demonstrated that the addition of fostamatinib to standard of care (SOC), which included the antiviral remdesivir and the steroid dexamethasone, was well tolerated and associated with clinically meaningful improvement in clinical outcomes in hospitalized COVID-19 patients who required supplemental oxygen. While the study was not powered to test clinical efficacy, numerous prespecified secondary endpoints consistently favored fostamatinib, including mortality, time to sustained recovery, change in ordinal scale assessment, number of days on oxygen, and number of days in the ICU, suggesting that fostamatinib may provide an additional therapeutic benefit compared to current SOC alone.

The Phase 2 double-blind, placebo-controlled clinical trial sponsored by the NHLBI, part of the NIH, in collaboration with Inova Health System, enrolled fifty-nine hospitalized patients with COVID-19 who were a 5 to 7 on the 8-point ordinal scale (requiring supplemental oxygen via nasal cannula or non-invasive ventilation, requiring mechanical ventilation or extracorporeal membrane oxygenation). Patients were randomly assigned to one of two cohorts: fostamatinib plus SOC and matched placebo plus SOC (1:1). Treatment was administered orally twice daily for 14 days, with a follow-up period through day 60. The primary outcome was the cumulative incidence of SAEs by Day 29. Notably, all patients received dexamethasone (or other steroid) and remdesivir.