Rigel Pharmaceuticals, Inc. (Nasdaq: RIGL), today announced that the U.S. Food and Drug Administration (FDA) has 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 FDA noted in their response that they remain committed to working with Rigel in the development of fostamatinib for COVID-19 as the Company is currently conducting a larger Phase 3 clinical trial evaluating fostamatinib in hospitalized patients with COVID-19.
"With new virus variants spreading and vaccination rates plateauing, there remains a need for therapies that can improve outcomes for hospitalized patients, particularly patients suffering from hyperinflammatory COVID-19-related complications," said Raul Rodriguez, president and CEO of Rigel. "The Rigel team continues to focus on enrolling our Phase 3 clinical trial, which we anticipate completing later this year, and we look forward to providing further safety and efficacy data from this larger, 308-patient trial of fostamatinib in COVID-19 patients. If this trial meets its endpoints, we plan to resubmit our EUA application with this additional data."
Fostamatinib Clinical Development Program in COVID-19
The broader clinical development program for fostamatinib is comprised of three ongoing studies and a recently completed Phase 2 study. These studies are evaluating a wide range of hospitalized patients, including those not on oxygen therapy, who are experiencing mild to severe COVID-19-related complications:
Rigel-led Phase 3 Trial. This ongoing Phase 3 clinical trial will evaluate the safety and efficacy of fostamatinib in hospitalized COVID-19 patients without respiratory failure that have certain high-risk prognostic factors. This multi-center, double-blind, placebo-controlled study will enroll ~308 evaluable patients to either fostamatinib plus SOC or matched placebo plus SOC (1:1). The primary endpoint of this study is the proportion of patients who progress to severe/critical disease within 29 days. The study has enrolled ~176 patients as of August 12, 2021, and enrollment is expected to be complete by year-end. More detail on the study can be found on clinicaltrials.gov: NCT04629703.
ACTIV-4 Host Tissue Phase 3 Trial. The Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) study, initiated and funded by the National Heart Lung and Blood Institute (NHLBI), part of the National Institutes of Health, is a multi-site, randomized, placebo-controlled trial of therapies, including fostamatinib, targeting the host response to COVID-19 in hospitalized patients. The Master Protocol is designed to be flexible in the number of study arms, the use of a single placebo group, and the stopping and adding of new therapies. Each active arm will include approximately 300 patients. Eligible participants will include patients hospitalized for COVID-19 with laboratory-confirmed SARS-CoV-2 infection on oxygen therapy. The primary outcome is oxygen-free days through day 28. Secondary outcomes include hospital mortality, use of mechanical ventilation, and WHO scale scores. The study enrolled its first patient on July 22, 2021. More detail on the study can be found on clinicaltrials.gov: NCT04924660.
Imperial College of London IST. The Imperial College London Investigator-Sponsored Trial (IST) is a two-stage, open-label, controlled clinical trial of patients randomized (1:1:1) to fostamatinib, ruxolitinib, or SOC. The primary objective will be to determine the efficacy of fostamatinib and the efficacy of ruxolitinib compared to SOC to reduce the proportion of hospitalized patients progressing from mild or moderate to severe COVID-19 pneumonia. Rigel is providing support for this trial along with Novartis. More detail on the study can be found on clinicaltrial...
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