NATIONAL HARBOR, Md.—An investigational treatment safely and effectively lowers elevated plasma intact parathyroid hormone (iPTH) levels in patients with stage 3 or 4 chronic kidney disease and vitamin D deficiency, researchers reported at the National Kidney Foundation 2012 Spring Clinical Meetings.
The treatment, CTAP101 Capsules, is a first-in-class, modified-release oral formulation of calcifediol that is being developed as a treatment for secondary hyperparathyroidism (SHPT).
Stuart Sprague, DO, of NorthShore University Health System in Evanston, Ill., and colleagues tested CTAP101 Capsules in a Phase 2b, randomized, double-blind, placebo-controlled study that included 78 stage 3 or 4 CKD patients with vitamin D insufficiency and SHPT. Subjects were assigned to receive one of three formulations of the active drug (30, 60, or 90 mcg) or a matching placebo for six weeks. Serum total 25-hydroxyvitamin D (25D), plasma iPTH, serum calcium, and serum phosphorus were monitored at least weekly.
Compared with placebo, the capsules increased serum total 25D and decreased plasma iPTH significantly. Low serum total 25D was corrected to adequate levels (30 ng/mL or higher) in nearly every treated subject. Plasma iPTH was decreased by 30% or more from pre-treatment levels in 39%, 65%, and 63% of subjects treated with doses of 30, 60, and 90 mcg, respectively. CTAP101 had no adverse effects on serum calcium, serum phosphorus, or urinary calcium throughout the six-week treatment period or the six-week follow-up period.
The product is being developed by Cytochroma, whose president and CEO Charles W. Bishop, MD, stated in a press release that CTAP101 Capsules performed well above expectations. “No marketed therapy both effectively controls elevated serum parathyroid hormone levels and corrects the underlying vitamin D insufficiency in CKD patients,” he said. “These strong data indicate that CTAP101 Capsules is a highly differentiated product compared to current treatment options. We look forward to initiating Phase 3 trials later this year.”