Tokai Pharmaceuticals’ Reformulated Galeterone Demonstrates Robust PSA Reductions in Advanced Prostate Cancer Patients

CAMBRIDGE, Mass. and SAN FRANCISCO, January 29, 2014 – Tokai Pharmaceuticals, Inc., a biopharmaceutical company focused on developing new treatments for prostate cancer and other hormonally driven cancers, today announced positive interim results from the Phase 2 ARMOR2 study with reformulated galeterone (TOK-001) which demonstrated promising reductions in prostate-specific androgen (PSA) levels, a marker of prostate cancer growth in patients with castration-resistant prostate cancer (CRPC). To date, galeterone has been well tolerated.

These data will be presented tomorrow in a poster presentation (abstract #71) by Mary-Ellen Taplin, M.D., associate professor of medicine, director of genitourinary clinical research, Dana-Farber Cancer Institute, Harvard Medical School, and co-principal investigator of the ARMOR2 trial, at the American Society of Clinical Oncology Genitourinary Cancers Symposium (ASCO GU) in San Francisco.

“The interim results of the ARMOR2 trial utilizing the new formulation of galeterone demonstrate an encouraging efficacy and safety profile and support the potential clinical benefit of galeterone’s multiple mechanisms of action in prostate cancer,” said Dr. Taplin.“ While there have been important improvements in the treatment of CRPC over the past several years, there remains a need for new treatment options with improved efficacy and tolerability.”

The ongoing ARMOR2 trial is a two-part Phase 2 study designed to confirm the dose of reformulated galeterone (Part 1) and demonstrate safety and efficacy in four distinct CRPC patient cohorts (Part 2). Approximately 136 patients are expected to be enrolled in the study. At the conclusion of Part 1 of the study, a once-daily galeterone dose of 2550 mg was selected for Part 2 based upon review of safety, efficacy and pharmacokinetic data. Interim data shows that for 39 patients followed for at least 12 weeks across all doses, 79% achieved a PSA decline of at least 30% (PSA30) and 67% achieved a PSA decline of at least 50% (PSA50). The most mature dataset is in metastatic treatment naïve CRPC where interim data in 21 patients show 90% achieved a PSA30 and 81% achieved a PSA50. In addition, initial data in abiraterone refractory patients shows both biochemical activity and stable disease.

Galeterone was well tolerated with (94%) of reported adverse events (AEs) Grade 1 or 2. There were no reported cases of seizures or cases of mineralocorticoid excess (ME). Consistent with ARMOR1 results, no patients received prednisone.

“We believe these data demonstrate the potential of reformulated galeterone to be an important new treatment option for CRPC patients,” said Jodie Morrison, president and chief executive officer of Tokai Pharmaceuticals. “ The robust PSA responses in treatment naïve patients, early signs of pharmacological responses in refractory patients and the safety profile observed to date support the potential for a differentiated profile for galeterone in comparison to other second generation anti-hormonal treatments. The results from the ARMOR2 trial will be used to support future development plans including defining the designs of Phase 3 trials we expect to be prepared to initiate in the second half of this year.”

Prior to ARMOR2, ARMOR1 was conducted in 49 CRPC patients and demonstrated clinical proof-of-concept with both PSA reductions and radiographic responses observed. Galeterone was well tolerated at all doses and there were no reports of seizure or secondary ME. However, the drug formulation used in ARMOR1 exhibited inconsistent gastrointestinal absorption due to a significant food effect. Prior to initiating ARMOR2, galeterone was reformulated as a spray dried dispersion which mitigated the food effect and substantially increased drug exposure.

About Galeterone

Galeterone (TOK-001), is a first-in-class, multi-targeted, oral small molecule drug being developed for the treatment of castration-resistant prostate cancer (CRPC) that disrupts androgen receptor (AR) signaling, the key driver of CRPC, via multiple mechanisms of action. Galeterone is the only drug in development or on the market that combines all three of these mechanisms in a single compound to treat CRPC. Galeterone is differentiated from other second-generation anti-hormonal treatments for CRPC due to fact that it does not bind to GABAa (no class effect risk for seizures) and exhibits a selective CYP17 lyase over hydroxylase inhibition profile (no prednisone requirement).

Tokai is investigating galeterone as part of the ARMOR (Androgen Receptor Modulation Optimized for Response) clinical development program in patients with CRPC. Clinical proof-of-concept of galeterone in CRPC has been completed and results from the ongoing ARMOR2 Phase 2 trial will be used to define the Phase 3 trials planned for initiation in the second half of 2014.

About Tokai Pharmaceuticals

Tokai Pharmaceuticals is a biopharmaceutical company focused on developing new treatments for prostate cancer and other hormonally driven cancers . The company’s lead drug candidate, galeterone (TOK - 001), is a first - in - class , multi - targeted, oral small molecule drug being developed for the treatment of patients with castration - resistant prostate cancer (CRPC). Based in Cambridge, Massachusetts, Tokai is backed by Apple Tree Partners , Novartis Ven ture Fund and the Satter Foundation . For more information on the company and galeterone, please visit www.tokaipharma.com .

Posted: January 2014

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