OPKO Health, Inc. OPK announced that it has initiated a phase II study — REsCue — to evaluate its vitamin D3 analog drug, Rayaldee, as a potential treatment for mild-to-moderate COVID-19.The study will enroll 160 patients including patients with stage 3 or 4 chronic kidney disease (“CKD”), who are at higher risk of developing more severe illness.The REsCue study will evaluate a four-week treatment regimen of Rayaldee in COVID-19 outpatients followed by two weeks of follow-up. Patients will receive 300 mcg per day on first three days of treatment followed by 60 mcg per day for the rest of the treatment period or a placebo. The primary endpoints of the study are to raise and maintain serum total 25-hydroxyvitamin D (25D) within the range of 50-100 ng/mL, and time to resolution of COVID-19 symptoms. The study’s secondary endpoints include new cases of emergency room or urgent care visits, patient’s oxygen saturation below 94%, any need for and duration of hospitalizations, requirement for mechanical ventilation, mortality rate, and severity and duration of illness evidenced by quality-of-life measures.The company anticipates top-line data from the phase II study by the end of 2020. The company remains hopeful about its drug as potential treatment for COVID-19 as several independent studies have demonstrated that there is a correlation between vitamin D status and COVID-19 risk and severity.Please note that Rayaldee is approved for treating secondary hyperparathyroidism in adults with stage 3 or 4 CKD and vitamin D insufficiency.Shares of OPKO Health have gained 114.3% so far this year compared with the industry’s increase of 16.8%. Currently, there are no FDA-approved treatments for the severe illness caused by SARS-CoV-2. However, several pharma companies are developing treatments/antibodies for different stages of COVID-19. Leading among them is Gilead’s (GILD) Veklury (remdisivir), which has already received an emergency use authorization from the FDA for treating all hospitalized patients with COVID-19.Earlier this week, Eli Lilly LLY and partner Incyte INCY announced that a phase III study evaluating their rheumatoid arthritis drug, Olumiant, in combination with remdesivir for hospitalized patients with COVID-19 infections met the primary endpoint of reduction of time to recovery in comparison with remdesivir alone.Roche RHHBY is conducting a late-stage study on its arthritis drug, Actemra/RoActemra, in combination with remdesivir in hospitalized patients with severe COVID-19 pneumonia.We note that Regeneron also initiated studies on REGN-COV2, a novel investigational antibody cocktail treatment designed to prevent and treat the SARS-CoV-2 virus this month. Moreover, Amgen’s Otezla is being investigated as a potential immunomodulatory treatment in patients hospitalized with SARS-CoV-2 infection in multiple COVID-19 platform trials. Vanda Pharmaceuticals' is evaluating its pipeline candidate, tradipitant, for treating COVID-19 pneumonia.OPKO Health, Inc. Price OPKO Health, Inc. price | OPKO Health, Inc. QuoteZacks RankOPKO Health currently carries a Zacks Rank #2 (Buy). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.More Stock News: This Is Bigger than the iPhone!It could become the mother of all technological revolutions. Apple sold a mere 1 billion iPhones in 10 years but a new breakthrough is expected to generate more than 27 billion devices in just 3 years, creating a $1.7 trillion market.Zacks has just released a Special Report that spotlights this fast-emerging phenomenon and 6 tickers for taking advantage of it. If you don't buy now, you may kick yourself in 2021.Click here for the 6 trades >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Roche Holding AG (RHHBY): Free Stock Analysis Report Incyte Corporation (INCY): Free Stock Analysis Report Eli Lilly and Company (LLY): Free Stock Analysis Report OPKO Health, Inc. (OPK): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research