Cytochroma announces positive Phase I results for CTAP201 Injection in
hemodialysis patients

MARKHAM, ON, May 6 /CNW/ - 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.

About Chronic Kidney Disease (CKD)

CKD is a condition characterized by a progressive decline in the function of the kidney, which is normally responsible for excreting waste and excess water from the body, and for regulating various hormones. CKD is classified in five different stages - mild (stage 1) to severe (stage 5) disease - as measured by the kidney's glomerular filtration rate. According to the National Kidney Foundation, CKD afflicts over 26 million people in the United States (U.S.), including more than eight million patients with moderate (stages 3 and 4) and severe (stage 5) forms of CKD. In stage 5 CKD, kidney function is minimal to absent and patients require regular dialysis or a kidney transplant for survival.

About Secondary Hyperparathyroidism (SHPT)

SHPT is a condition commonly associated with CKD in which the parathyroid glands secrete excessive amounts of parathyroid hormone (PTH). Excess PTH secretion arises as a result of impaired kidneys that are unable to produce sufficient quantities of vitamin D hormones to maintain a state of balance (homeostasis) between calcium and phosphorus in the body. Prolonged elevation of PTH causes excessive calcium and phosphorus to be released from bone into the blood, leading to elevated serum calcium and phosphorus, softening of the bones (osteomalacia) and calcification of vascular tissues. SHPT affects 40-60% of patients with moderate CKD and approximately 90% of patients with severe CKD.

About CTAP201 Injection

CTAP201 is a hormone naturally produced in the human body from vitamin D(2) and is the active metabolite of the marketed prohormone doxercalciferol. It has been formulated for intravenous administration as CTAP201 Injection, a product under development to treat SHPT in CKD patients. In preclinical CKD models, the product has exhibited excellent parathyroid hormone-lowering activity with limited impact on serum calcium and phosphorus. CTAP201 Injection is being developed under a 505(b)(2) regulatory pathway, and may provide nephrologists with a new alternative to treat SHPT more safely and effectively.

About Cytochroma

Cytochroma is a clinical stage specialty pharmaceutical company focused on developing and commercializing proprietary products to treat and prevent the clinical consequences of vitamin D insufficiency and SHPT associated with CKD. The Company specializes in developing new vitamin D therapies which are designed to safely and effectively treat patients with stage 3, 4 or 5 CKD. Cytochroma has three product candidates in clinical development for CKD patients: CTA018 Injection and CTAP201 Injection are being developed for the treatment of SHPT in stage 5 CKD, while CTAP101 Capsules are being developed for the treatment of vitamin D insufficiency and associated SHPT in stage 3 and 4 CKD. CTA018 Injection is being developed in partnership with Mitsubishi Tanabe Pharma Corporation for the U.S. and Asian markets, and Cytochroma retains co-promotion rights for this product in the U.S. In addition, Cytochroma is developing novel therapies to treat hyperphosphatemia in CKD patients.

For more information about Cytochroma, please visit www.cytochroma.com.

For further information: Cytochroma Investors: Gordon Ngan, Executive Director, Corporate Development, Tel: [phone] ext. 333, [email protected]; Cytochroma Media: Robert Stanislaro (FD), Tel: [phone], [email protected]