OPKO Health, Inc. (NYSE: OPK), has surpassed 50% enrollment in the first phase 3 trial of RayaldyTM 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 RayaldyTM 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 RayaldyTM or placebo. Dosing with RayaldyTM is titrated, as necessary, to achieve the desired blood concentration and the targeted reduction in PTH.
"RayaldyTM 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 RayaldyTM effectively and safely treats both SHPT and the underlying vitamin D insufficiency."