On Jun. 1, 2020, OPKO Health announced the U.S. Food and Drug Administration (FDA) had authorized OPKO to undertake a Phase 2 trial with RAYALDEE as a treatment for patients with mild-to-moderate COVID-19. The trial, entitled ‘A Randomized, Double-Blind Placebo-Controlled Study to Evaluate the Safety and Efficacy of RAYALDEE (calcifediol) Extended-release Capsules to Treat Symptomatic Patients Infected with SARS-CoV-2 (REsCue),’ was estimated to enroll 166 subjects, including many with stage 3 or 4 chronic kidney disease.

The REsCue trial will have 4 weeks of treatment with RAYALDEE or placebo and 2 weeks of follow-up. The objective is to raise and maintain serum total 25-hydroxyvitamin D (25D) within the range of 50-100 ng/mL in order to mitigate COVID-19 severity.

COVID-19 disproportionately afflicts patients with obesity, older age, darker skin or CKD, all of which are risk factors for reduced serum 25D. Raising 25D sufficiently with supplements is difficult.

RAYALDEE is an extended-release oral formulation of calcifediol, a prohormone of calcitriol, the active form of vitamin D₃.  The product is the first and only medicine approved by the U.S. FDA for raising serum total 25D and lowering blood levels of intact parathyroid hormone (iPTH). RAYALDEE, approved to treat secondary hyperparathyroidism (SHPT) in adults with stage 3 or 4 CKD and vitamin D insufficiency, was launched in November 2016. 

OPKO is a multinational biopharmaceutical and diagnostics company that seeks to establish industry-leading positions in large, rapidly growing markets by leveraging its discovery, development, and commercialization expertise and novel and proprietary technologies.