First Patient Inducted into Phase II Clinical Trial Evaluating Galeterone
Building on the success of Phase I clinical trials, Tokai Pharmaceuticals has advanced its lead prostate cancer drug for the treatment of advanced disease into Phase II trials this week.
December 17, 2012—Galeterone, also known as TOK-001, is an oral prostate cancer candidate drug. The triple-action therapeutic thwarts prostate cancer cell proliferation by targeting the primary driver of treatment-resistance disease—androgen receptor signaling—in various ways. Researchers hope this three-in-one-punch drug may provide a new option to men with advanced disease. PCF-funded researcher, Dr. Philip Kantoff, director at the Lank Center for Genitourinary Oncology at the Dana-Farber Cancer Institute—an institution that will participate in the Phase II clinical trial of galeterone—said in a press release put out by the company: “Galeterone is unique in that it is the first and only single agent therapeutic that combines three distinct approaches to attack prostate cancer….We are excited to further explore the clinical utility of galeterone in [treatment-resistant prostate cancer], a cancer for which additional new therapies with improved tolerability and novel mechanisms of action are needed to address the emergence of resistance of existing agents.”
The male androgen testosterone fuels prostate cancer and galeterone works by blocking testosterone synthesis, blocking testosterone’s ability to bind to its androgen receptor and, finally, by limiting overall androgen receptor levels in the body.
The results of the Phase I trials were presented earlier this year at both the American Society of Clinical Oncology (ASCO) and the American Association for Cancer Research (AACR). The data presented showed that of the 49 chemotherapy-naïve patients enrolled in the early dose-finding trial, 11 patients (or 22 percent) experienced declines in their PSA levels of greater than 50 percent. Another 26 percent of patients had PSA declines ranging between 30 to 50 percent. (PSA is prostate specific antigen, a marker of disease progression in prostate cancer patients.) The study found the drug to be well-tolerated at the optimal dosage and a few patients experienced a significant reduction in tumor size, as shown in CT scans. Patient responders were given the option to continue treatment with galeterone in an extension arm of the trial.
Dr. Robert B. Montgomery, a PCF-funded researcher and the lead author on the poster of the Phase I study results said in a media release at the time that they hope the drug will address treatment-resistance in a novel fashion. “Cancer cells mutate and change to get around drugs, and resistance to therapy is a growing concern in treating cancer,” he said, adding that the unique three-pronged action of galeterone “may help to prevent resistance….and could potentially be more effective than drugs we know have.”
For the Phase II trial, Tokai plans to enroll 196 patients, the first of whom has already begun treatment. This trial will use a slightly reformulated version of galeterone that has improvements in its uptake and absorption in the body. In addition, the Phase II trial will not only include men who are chemotherapy-naïve, but also men whose disease has progressed while taking Zytigia, another androgen-ablation drug. All patients will be evaluated to determine galeterone’s effects upon PSA levels and their overall safety profiles.