Synta Pharmaceuticals Corp. (SNTA) plunged the most in four years after its experimental lung cancer drug showed less benefit than anticipated in a study.
Patients given the company’s ganetespib treatment along with docetaxel, a standard chemotherapy for lung cancer, had a 32 percent increase in survival compared with those given docetaxel only, Synta said. The results from the company-funded study, presented today at the American Society of Clinical Oncology meeting in Chicago, showed less benefit than the previous update of the study, released in October at another scientific meeting.
The shorter survival result “was considered a disappointment by investors, leading to today’s sell-off,” George Zavoico, an analyst with MLV & Co. in New York, said in a note to clients. “However, it is our view that even a 4-plus month improvement in median overall survival in this difficult-to-treat patient population is a significant achievement that must now be confirmed.”
Researchers in the study included 252 patients with advanced non-small cell lung adenocarcinoma. Adenocarcinoma accounts for almost half of the 170,000 cases of non-small cell lung malignancies diagnosed in the U.S. each year, according to the American Society of Clinical Oncology. Half of the patients in the trial received ganetespib plus docetaxel, while the other half were given just docetaxel.
Those given ganetespib had survival of 9.8 months compared with 7.4 months in the docetaxel-only group. The group reported an 18 percent reduction in the risk of death, which wasn’t statistically significant. Previously, research presented at the European Society for Medical Oncology on Oct. 1, showed a reduction in death risk of 31 percent.
Ganetespib works by blocking a protein, known as heat shock protein 90, that helps activate many cancer-promoting compounds in the body and supports the growth and survival of tumor cells. Results reported today were from the second of three stages of human testing generally required for marketing approval.
About 228,190 new cases of lung cancer, the leading cause of cancer death in men and women, will be diagnosed this year in the U.S., according to the American Cancer Society. If approved, ganetespib may be the first new drug for non-small cell lung adenocarcinoma in almost a decade, said Safi Bahcall, chief executive officer of Lexington, Massachusetts-based Synta.
“This is the first time we’re seeing a real survival advantage in this setting,” Bahcall said in a telephone interview. “This is a patient population where there hasn’t been a new drug in nine years. These results suggest real potential that this drug can move the needle on survival for these patients.”
Bahcall said the company could seek U.S. Food and Drug Administration clearance for the treatment in the next two years if a bigger trial, now under way, shows similar results. Synta also is studying the treatment in cancers of the breast, colon and blood.
Docetaxel, a generic medicine, is also sold by Sanofi (SAN) under the name Taxotere. Survival for patients in the ganetespib group who were diagnosed with their disease at least six months prior to treatment rose about 67 percent, the study showed. These patients are being studied in a separate trial.
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