Investigational therapy for hormone-resistant PCa shows survival advantage

The investigational compound ZD4054, an endothelin-A receptor antagonist, appears to positively impact overall survival in patients with hormone-resistant prostate cancer, according to the results of a randomized, double-blind, placebo-controlled, phase II study presented at the European Congress of Clinical Oncology in Barcelona.

The EPOC (Endothelin-A Proof Of Concept) Study included a total of 312 asymptomatic or mildly symptomatic hormone-resistant prostate cancer patients with bone metastases who were randomized into one of three treatment arms: ZD4054, 15 mg once daily; ZD4054, 10 mg once daily; or a once-daily placebo tablet. In addition to study treatment, all men randomized into the study received best supportive care.

The primary endpoint of the study was progression-free survival, and a secondary endpoint was overall survival. The progression-free survival data did not show a statistically significant difference between ZD4054 and placebo treatment arms. The updated phase II data show that patients who received ZD4054, 10 mg once daily, had a median overall survival of 24.5 months, patients who received ZD4054, 15 mg once daily, had a median overall survival of 23.5 months, and the placebo arm had a median overall survival of 17.3 months.

"The results from the EPOC study suggest that ZD4054, 10 mg once daily, may have the potential to increase the median overall survival time for men with asymptomatic or mildly symptomatic metastatic hormone-resistant prostate cancer," said principal investigator Nick James, MD, of the Institute for Cancer Studies, Birmingham, United Kingdom.

Side effects of ZD4054 in this study included headache, edema, and nasal congestion. A phase III trial program will begin this year.