Tokai unveils promising Phase I data for 'triple whammy' prostate cancer contender

Cambridge, MA-based Tokai Pharmaceuticals presented a promising set of Phase I data pointing to the early efficacy of its "triple whammy" pill for castration-resistant prostate cancer. The PSA levels in about half of the 49 patients in the dose-ranging study declined 30% or more in the trial, with 11 patients registering a plunge of 50% or more. PSA levels are a commonly used biomarker for prostate cancer at this stage of development.

Harvard investigators determined that galeterone, or TOK-001, worked largely as hoped in the study. Prostate cancer cells are fueled by androgen, a hormone produced in the testes. CRPC cells become resistant to currently used therapies by finding alternative means of spurring the development of androgen. Tokai's program is aimed at shutting down the three mechanisms involved in CRPC cases: preventing the body from synthesizing new androgen by inhibiting the CYP17 enzyme, blocking the androgen receptor and then degrading the receptor itself. 

In addition to the drop registered for PSA levels, Tokai noted that "CT scans revealed a significant reduction in tumor size for some patients."

Galeterone, then, is designed to do what Zytiga does, adds the same effect sought by Medivation's ($MDVN) closely watched MDV3100 and adds a third mechanism--a combination approach likely to excite specialists if the company can pull off a successful mid-stage study, followed by positive data in Phase III.

"Two of the hottest drugs in the field, we do in one pill," CEO Martin Williams tells FierceBiotech this morning. And even with the combinatorial approach, he adds that there's potential for a combo of their own, adding an mTOR inhibitor like Novartis' ($NVS) Afinitor would be a likely match.

Tokai announced last fall that it had rounded up $23 million in new venture capital commitments as it laid the groundwork for a Phase IIb study of the treatment, which should get under way in the second half of this year. Once that study is complete, says the CEO, the company can see about signing up a partner--though it is conceivable that they could raise the funds to accomplish Phase III on their own.

Before it goes into the mid-stage trial, Tokai plans to complete a crossover study to test a reformulation of the drug. Investigators wound up giving "too many pills" to patients in Phase I, says the CEO, which spurred the decision to reformulate the drug for more convenient dosing.

- here's the press release
- read the report from The Guardian