Epizyme Shares Climb on New Data for Cancer Drug

Xconomy Boston — 

Back in March, Epizyme regained most of the rights to a drug it’s been developing for a wide array of cancers. There’s still a long way to go, but the move appears prescient given some of the signs the Cambridge, MA-based company is seeing in early clinical trials.

This past weekend, Epizyme (NASDAQ: EPZM) offered up the latest data from a small, Phase 1 study of tazemetostat (previously known as EPZ-6438).

Epizyme says the data, disclosed at a medical meeting in Switzerland, show a few key early signals. First, nine out of 15 evaluable patients with advanced forms of Non-Hodgkin lymphoma (NHL)—very sick folks who have failed treatment with multiple therapies—have responded to Epizyme’s drug. Second, those responses appear to pick up over time. And third, no major safety problems have cropped up so far, leading management to suggest on a conference call this morning that the drug could be combined with other therapies in future studies, and potentially taken chronically without causing severe side effects.

Epizyme shares surged over 30 percent in midday trading on Monday.

Tazemetostat is a small molecule drug designed to switch off the activity of a specific enzyme—a type of histone methyltransferase called EZH2—that’s implicated in a variety of cancers. Epizyme had been developing the drug with the help of Japan’s Eisai, but in March bought back all commercial rights—aside from in Japan—for $40 million up front, potentially another $70 million in milestone payments, and royalties on drug sales outside of Japan.

So while Epizyme will still owe Eisai some cash if tazemetostat progresses—and is now picking up the tab for development costs—it also stands to benefit much more if the drug succeeds. Epizyme CEO Robert Gould (pictured above, left) said at the time that the move was made due to some better-than-expected results in a broader group of patients than the company had first envisioned—in certain types of blood cancers (follicular lymphoma and diffuse large B-cell lymphoma, or DLBCL) and solid tumors (so-called “INI-1 deficient” solid tumors).

The results have gotten better since then. In March, four of 10 patients had responded to Epizyme’s drug; now, nine of 15. Chief development officer Peter Ho said on a conference call with analysts this morning that the company has been noticing a pattern of “gradual but prolonged reduction of tumor mass” across all the different subtypes of NHL for which tazemetostat has been tested. One 78-year-old male with follicular lymphoma, for instance, had a partial response after 16 weeks and no trace of cancer after 32. Another lymphoma patient had no presence of cancer after 40 weeks, Ho said.

Epizyme has been enrolling patients in a Phase 2 study of EPZ-6438 of 150 patients with various forms of non-Hodgkin lymphoma, and a separate study in patients with INI-1 deficient solid tumors. Ho said on the call this morning that given the results Epizyme has seen so far, it intends to test tazemetostat in combination with what’s known as “R-CHOP” therapy (the standard of care for DLBCL, which consists of rituximab (Rituxan) plus a chemo regimen); or potentially with a B-cell targeting blood cancer drug (Epizyme hasn’t said which type specifically).

Epizyme should have another update coming shortly regarding its other drug, EPZ-5676: Celgene (NASDAQ: CELG) will decide whether to opt in to another year of a research collaboration between the two by July 8. Celgene has international rights to EPZ-5676. More data from patients with solid tumors are expected later this year as well.