OPKO Health has closed patient enrolment in the first Phase III trial of Rayaldy for the treatment of patients with secondary hyperparathyroidism (SHPT), stage 3 or 4 chronic kidney disease (CKD) and vitamin D insufficiency.
The trial is the first of two identical randomised, double-blind, placebo-controlled, multi-site trials, which are aimed at establishing the safety and efficacy of Rayaldy, a first-in-class oral vitamin D prohormone therapy, as a new treatment for SHPT.
Endpoints of the two trials include vitamin D status and changes in serum calcium, serum phosphorus and plasma intact parathyroid hormone (PTH).
Around 210 patients were recruited at some 40 US sites and were enrolled in each of the trial.
In the trials, patients being stratified by CKD stage and randomised in a 2:1 fashion to receive six months of treatment with either Rayaldy or placebo.
According to the company, top-line data from both trials is expected to be released in mid-2014.
The two Phase III trials are being followed by an open-label extension study, involving patients treated for an additional six months with Rayaldy. The company has so far enrolled 129 patients.
Rayaldy has a proprietary modified-release formulation designed to gradually and reliably raise serum total 25-hydroxyvitamin D (prohormone) concentrations to targeted levels at least 30 ng/mL, while avoiding upregulation of CYP24, a cytochrome P-450 enzyme that reduces the PTH lowering potency of current vitamin D supplements.
The company said that activation of calcifediol, the active ingredient in Rayaldy, by the kidney is tightly regulated, preventing excessive elevation of serum calcium and related side effects which encumber current vitamin D hormone therapies and promote vascular and renal calcification.
Following approval, Rayaldy will help serve CKD stage 3 and 4 patients in the US and elsewhere, with SHPT and vitamin D insufficiency.