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Tokai Pharma Shutters Prostate Cancer Drug Trial Early, Shares Crumble

Xconomy Boston — 

Tokai Pharmaceuticals has been trying to play catch-up for years in the fast-moving field of prostate cancer treatments. But that plan just took a major hit this morning.

Cambridge, MA-based Tokai (NASDAQ: TKAI) said that an independent data monitoring committee instructed the company to stop the big Phase 3 trial of its prospective prostate cancer drug, galeterone, early because the study was likely to fail: Galeterone wasn’t going to do better than enzalutamide (Xtandi) at stopping patients’ prostate cancer from spreading. Top-line data from the study, known as Armor3-SV, weren’t expected until next year.

Tokai said the recommendation wasn’t due to safety problems, but the news is nonetheless a big setback for the company, whose shares plummeted more than 63 percent, to $1.91 apiece, on Tuesday morning just after the announcement. Galeterone isn’t just Tokai’s most advanced drug, it’s the company’s only drug in clinical testing. Tokai went public at $15 per share in September 2014.

Tokai has been testing galeterone in various settings in prostate cancer, hoping to find the right niche for the drug. But its development plans are now up in the air. Tokai said it will evaluate the one mid-stage trial currently underway, in prostate cancer patients who have developed resistance to enzalutamide, and the other Phase 2 trial it had planned to run in patients who quickly progress after treatment with either enzalutamide or another prostate cancer drug, abiraterone (Zytiga). The future of both galeterone and the company are in doubt. Tokai had about $43.9 million in cash as of June 30.

“We are very disappointed by this outcome. An immediate priority is to analyze the unblinded study data in detail as we evaluate potential paths forward for galeterone and our pipeline,” said CEO Jodie Morrison, in a statement.

Tokai will hold a conference call this morning to discuss the results.

Tokai has been chasing after the big players in the prostate cancer field, namely Medivation and Astellas Pharma (which co-own enzalutamide), and Johnson & Johnson (abiraterone), which helped change the paradigm of treatment for prostate cancer. Both drugs have shown benefits for patients not just after they’re treated with chemotherapy, but before.

Tokai’s pitch with galeterone was to combine some of the best features of those two drugs into a single pill. The drug employs tactics used by both enzalutamide (an androgen blocker) and abiraterone (which targets an enzyme called Cyp17 lyase that’s required for androgen production), while also degrading the androgen receptor on tumor cells, in theory blocking the androgen hormones that feed prostate cancer tumors in three different ways. Given the way its drug is designed to work—and the intensely competitive field—Tokai first aimed to find a niche for itself treating prostate cancer patients who couldn’t be effectively treated by drugs like abiraterone or enzalutamide before branching out into other subsets of prostate cancer patients.

Tokai’s big test in that regard was Armor3-SV, a roughly 150-patient late-stage trial in prostate cancer patients whose tumor cells have an altered, “truncated” androgen receptor that rendered them unlikely to respond to enzalutamide or abiraterone.  Patients in the study were given either galeterone or enzalutamide once a day. The primary goal was to keep patients’ cancers from spreading—what’s known as progression-free survival—for longer than enzalutamide.

Apple Tree Partners held 35 percent of Tokai shares as of April, according to a regulatory filing. Novartis Bioventures (19.9 percent) also had a sizeable stake.

Check out this story for more on Tokai, which was formed in 2004 around work done by Angela Brodie and Vincent Njar of the University of Maryland School of Medicine.

Ben Fidler is Xconomy's Deputy Biotechnology Editor. You can e-mail him at bfidler@xconomy.com Follow @benthefidler

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