Tokai Pharmaceuticals, Inc., a US-based biopharmaceutical company focused on developing new treatments for prostate cancer, has received Fast Track designation from the US Food and Drug Administration (FDA) for its lead candidate, galeterone (TOK-001) for the potential treatment of metastatic castration-resistant prostate cancer (CRPC).

Tokai recently completed ARMOR1, a phase 1 proof-of-concept study of galeterone in patients with CRPC, part of the ARMOR (Androgen Receptor Modulation Optimized for Response) clinical development programme, and Tokai plans to initiate a phase 2 clinical trial in patients with CRPC in the second half of the year.

CRPC is an advanced, difficult-to-treat form of prostate cancer that occurs when the disease progresses despite the use of androgen deprivation therapy. Galeterone is a proprietary small molecule, oral drug for the treatment of CRPC that disrupts androgen receptor (AR) signaling, the key driver of CRPC, via a novel triple mechanism of action.

Galeterone selectively inhibits CYP17 lyase to prevent testosterone synthesis, antagonizes testosterone binding to the AR and degrades the AR protein. Results from the ARMOR1 clinical trial presented recently at the American Association for Cancer Research (AACR) Annual Meeting 2012 and the 2012 Annual Meeting of the American Society of Clinical Oncology (ASCO) show that galeterone demonstrated efficacy and was well-tolerated in patients with CRPC.

“We are very pleased with this Fast Track designation and believe the FDA’s decision further validates the potential therapeutic utility of galeterone for the treatment of prostate cancer,” said Martin D. Williams, president and chief executive officer, Tokai Pharmaceuticals. “Despite recent progress in prostate cancer treatment, CRPC often becomes resistant to androgen deprivation therapy and galeterone’s unique triple mechanism of action may offer an important therapeutic advance. We are very encouraged by the recent positive results from our ARMOR1 clinical study, and we look forward to advancing galeterone into phase 2 development in patients with CRPC later this year.”

Under the FDA Modernization Act of 1997, the Fast Track process was designed to facilitate the development and expedite the review of drug candidates intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs. A drug that receives Fast Track designation is eligible for accelerated approval, which provides for a potential approval by the FDA on the basis of a demonstrated effect on a surrogate endpoint deemed reasonably likely to predict clinical benefit, and rolling review, which facilitates the submission of individual sections of a New Drug Application (NDA) as they are completed for review by FDA.

Most drugs that are eligible for Fast Track designation are also considered appropriate to receive Priority Review, designed to reduce the time required for FDA review. In addition, Fast Track designation for a potential drug may allow more frequent meetings between the sponsor and FDA to discuss the proposed development plan and ensure collection of appropriate data needed to support approval, as well as possibly more frequent written correspondence from FDA about such matters as the suitability of designs for proposed clinical trials.

Galeterone is a proprietary small molecule, oral drug for the treatment of prostate cancer that disrupts androgen receptor signaling via a novel triple mechanism of action. In preclinical studies, galeterone acts as a highly selective CYP17 lyase inhibitor, as an androgen receptor antagonist, and decreases androgen receptor levels in prostate tumors – the only drug in development that has been shown to exhibit all three of these properties.

In galeterone, these three distinct mechanisms of action are combined in one therapeutic compound.