Cytochroma reports positive results from Phase I trial for CTAP201 Injection in hemodialysis patients

May 6 2010

Cytochroma today announced positive Phase I results for CTAP201 Injection, a product being developed to treat secondary hyperparathyroidism in hemodialysis patients. The study demonstrated that single intravenous doses of 1 and 3 mcg of CTAP201 were safe and well tolerated. It also identified a starting dose of 2 mcg for subsequent pivotal trials intended to establish the product's safety and efficacy in the targeted population.

"CTAP201 Injection fully met our expectations in the initial clinical trial," stated Joel Z. Melnick, M.D., Cytochroma's Vice President, Clinical Research and Development. "During treatment, we observed similar serum parathyroid hormone responses, but lower levels of serum calcium, with CTAP201 Injection compared with doxercalciferol injection. Serum phosphorus trended lower with CTAP201. Currently available therapies do not allow most hemodialysis patients to maintain simultaneous and adequate control of parathyroid hormone, serum calcium and serum phosphorus."

The Phase I clinical trial was an open label pharmacokinetic cross-over study comparing CTAP201 Injection to doxercalciferol (Hectorol(R)) injection in 24 hemodialysis patients in two treatment cohorts. Both cohorts received a single dose of CTAP201 and a single dose of doxercalciferol, separated by a two-week washout. The treatment order was balanced by randomization. The first cohort received 1 mcg of CTAP201 and 4 mcg of doxercalciferol while the second cohort received 3 mcg of CTAP201 and 6 mcg of doxercalciferol. Laboratory assessments included serum parathyroid hormone, calcium, phosphorus and the calculated calcium-phosphorus product.

Analysis of the data concluded that CTAP201 Injection is approximately twice as effective as doxercalciferol injection in raising blood vitamin D hormone levels. Further, serum calcium was lower after treatment with CTAP201 than after doxercalciferol. Adverse events were mostly mild or moderate and unrelated to study drug. Based on these data, the therapeutic dose of CTAP201 Injection is expected to be half that of doxercalciferol injection.