OPKO Health has reported initial data from the Phase II clinical trial which showed that Rayaldee was effective for the treatment of mild-to-moderate Covid-19.
Rayaldee is an extended-release oral form of calcifediol, which is a calcitriol prohormone, the active form of vitamin D3.
The randomised, double-blind, placebo-controlled trial analysed the safety and efficacy of Rayaldee to treat Covid-19 in symptomatic individuals.
It enrolled 171 subjects in the outpatient setting at multiple trial centres in the US. They were categorised in a 1:1 ratio to receive the oral drug or placebo for four weeks.
In the 42-day trial, Covid-19 symptoms were self-reported every day using the FLU-PRO Plus questionnaire, an outcome tool proven for upper respiratory tract infections.
Furthermore, blood samples and safety analysis were conducted every seven days.
Initial results from the trial showed that enhancing vitamin D status with the therapy led to early resolution of respiratory symptoms linked to Covid-19.
Data showed that a primary efficacy goal neared the targeted serum 25D level.
On treatment with Rayaldee, mean serum 25D levels rose to 82ng/mL by day seven and were maintained throughout the study, with 88% of patients achieving the targeted level versus placebo.
The advantage of inversing serum 25D on the time to resolution of five symptoms of the disease was the trial’s second primary efficacy goal. The symptoms included breathing trouble, congestion in the chest, dry or hacking cough, body pain and chills and shivering.
When serum 25D was raised on days 7 and 14, findings showed that the three symptoms linked to respiratory function resolved more quickly with chest congestion clearing 3.4 days sooner.
Resolution of chest congestion was observed four days earlier in participants who attained a rise in serum 25D of a minimum of 25ng/mL.
As symptoms not linked to respiratory function were unresponsive to the therapy, the meantime to resolution for all five symptoms was not substantially different between the trial arms, OPKO noted.
Rayaldee treatment offered no significant changes on safety endpoints such as vital signs, physical examinations, side effects, electrocardiograms and biochemical analysis.
In August this year, the company concluded participant enrolment in the Phase II REsCue trial of Rayaldee for mild-to-moderate Covid-19 treatment.