Synta Pharma rebounds on early results from drug study for breast cancer

Synta Pharmaceuticals ($SNTA) revealed some early signs of efficacy from a small sampling of breast cancer patients in a midstage study of its candidate ganetespib. Though very preliminary, the results and news that the study would advance to the next stage sparked a rally in Synta's shares.

Shares of Synta jumped 40.9% to $7.13 as of 3:30 p.m. ET today, recovering some of the lost value of the stock this year. Its stock price is still off about 20% year-to-date. As TheStreet's Adam Feuerstein reported, Lexington, MA-based Synta's decision to leap into late-stage development of ganetespib in lung cancer before completing the Phase II study of the drug in that disease has drawn ire on Wall Street.

Has Synta gone too far in promoting the preliminary results of the Enchant-1 study of ganetespib in breast cancer? Tumors shrank in two patients on the Hsp90 inhibitor with HER2-positive breast cancer and the same number of patients with triple-negative disease. These data come from just 15 of 70 patients expected to enroll in the Phase II study, however.

"Ganetespib may hold promise as a breast cancer treatment, but a signal of activity derived from 70 patients would be a lot more convincing than from 15 patients," Feuerstein wrote, "particularly in a study where the company has the ability to monitor every patient's results in real time."

Synta CEO Safi Bahcall

Synta CEO Safi Bahcall has led a credible comeback built around ganetespib, after the Phase III fiasco involving its drug elesclomol in myeloma four and half years ago triggered a meltdown in its stock price. Investors are willing to forgive failures in biotech, yet Synta is under pressure to deliver a winner with ganetespib.

Synta is shooting for some big-ticket markets such as lung and breast cancers, both of which affect large numbers of patients who need new treatment options. This year the CDC expects nearly 300,000 new cases of breast cancer, for example, and 15% of all cases are considered triple-negative and lack targeted treatments, according to the company.

- here's the release
- check out TheStreet's article
- and Reuters' report