OPKO reports more than 50% enrollment in phase 3 trial of Rayaldy for treatment of secondary hyperparathyroidism

OPKO Health, Inc.May 24 2013

OPKO Health, Inc. (NYSE: OPK), has surpassed 50% enrollment in the first phase 3 trial of Rayaldy^TM to treat patients with secondary hyperparathyroidism (SHPT), stage 3 or 4 chronic kidney disease (CKD) and vitamin D insufficiency. This trial is the first of two identical randomized, double-blind, placebo controlled, multi-site studies intended to establish the safety and efficacy of Rayaldy^TM as a new treatment for SHPT in the targeted population. The endpoints of both studies, which will be conducted in parallel, include vitamin D status and changes in serum calcium, serum phosphorus and plasma intact parathyroid hormone (PTH).

“Secondary hyperparathyroidism develops in CKD patients due to vitamin D insufficiency or declining kidney function”

Each of the phase 3 trials will involve 210 patients recruited at approximately 40 sites in the U.S. These patients are being stratified by CKD stage and randomized in a 2:1 fashion to receive six months of treatment with either Rayaldy^TM or placebo. Dosing with Rayaldy^TM is titrated, as necessary, to achieve the desired blood concentration and the targeted reduction in PTH.

"Rayaldy^TM is being developed as a much needed and safer alternative to currently used activated vitamin D hormones," commented Dr. David Bushinsky, Chief of Nephrology at the University of Rochester. "Activated vitamin D hormone therapy is problematic in CKD patients with secondary hyperparathyroidism arising primarily from vitamin D insufficiency since it further stimulates catabolism (breakdown) of the available vitamin D stores and is often associated with hypercalcemia, a side effect linked to vascular calcification."

"Secondary hyperparathyroidism develops in CKD patients due to vitamin D insufficiency or declining kidney function," explained Joel Z. Melnick, M.D., Vice President, Clinical Research and Development of OPKO's Renal Division. "Most CKD patients have insufficient stores of vitamin D due to the abnormal upregulation of CYP24, an enzyme which specifically destroys vitamin D and its metabolites. Many recent studies in CKD patients have demonstrated that over-the-counter and presently available prescription vitamin D supplements cannot reliably raise blood vitamin D prohormone levels or effectively treat SHPT. In contrast, our phase 2b trial has demonstrated that Rayaldy^TM effectively and safely treats both SHPT and the underlying vitamin D insufficiency."