On Jun. 29, 2021, Rigel Pharma announced that fostamatinib, the Company’s novel oral spleen tyrosine kinase (SYK) inhibitor, had been selected for a National Institutes of Health (NIH) ACTIV-4 (Accelerating COVID-19 Therapeutic Interventions and Vaccines) trial in hospitalized patients with COVID-19.

The trial, being conducted in collaboration with the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health (NIH), and Inova Health System, met its primary endpoint of safety. Fostamatinib reduced the incidence of Serious Adverse Events (SAEs) by half. By day 29, there were three SAEs in the fostamatinib plus standard of care (SOC) group of thirty patients compared to six SAEs in the placebo plus SOC group of twenty-nine patients. Of these, there was a reduction for the disease related SAE of hypoxia in the fostamatinib group compared to placebo (1 vs 3, respectively; p=0.29).

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