April 9, 2012

Drug Effective Against Prostate Cancer

(Ivanhoe Newswire) -- Do you or someone you know suffer from advanced prostate cancer (CRPC)? A new treatment may be available that can help treat the deadly disease.

Castration-resistant prostate cancer (CRPC) is an advanced form of prostate cancer that occurs when the disease progresses after treatment with androgen deprivation therapy.

A drug called galeterone works against CRPC by blocking the androgen receptor, reducing levels of the ligand that binds to the receptor and degrading the androgen receptor protein.

"This drug has a novel combined mechanism of action," R. Bruce Montgomery, M.D., co-author, at the University of Washington School of Medicine in Seattle, Wash, was quoted as saying. "Cancer cells are sly and mutate to get around drugs. The fact that this drug hits the prostate cancer cell in three different ways may help prevent resistance. It is a well-tolerated drug that could potentially be more effective than drugs we have now."

For the study, Montgomery and colleagues assigned 49 patients with CRPC to one of eight dose regimens in single or split oral escalation doses of 650 mg, 975 mg, 1,300 mg, 1,950 mg or 2,600 mg every day for 12 weeks. None of the patients had received chemotherapy for their prostate cancer.

Researchers found that no patients reached a maximum tolerated dose. Most side effects were minimal and included fatigue, nausea and diarrhea. Researchers observed transient, increased liver function tests in 15 patients, many of whom were asymptomatic. Eleven of these patients temporarily stopped galeterone treatment, and six returned to treatment with no recurring liver function test elevations. Only one serious complication occurred involving rhabdomyolysis during simvastatin therapy.

In early adequacy tests, 49 percent of patients had prostate-specific antigen (PSA) reductions of 30 percent or more; 11 of these patients had reductions of 50 percent or more. In addition, CT scans showed reduction in tumor size for some patients.

"Because the androgen receptor controls PSA expression, improved PSA response shows that the drug is getting to the target," Montgomery said. "For the majority of patients, to reduce their PSAs by 30 percent or more is quite good in a phase I dose-finding trial."

Researchers plan to investigate long-term safety and an assessment of effectiveness in a phase II study that Tokai Pharmaceuticals has planned for the second half of 2012.

SOURCE: AACR Annual Meeting 2012, March 31, 2012