NEW YORK -- ArQule Inc. stock lost more than half its value in Tuesday trading after the company said it stopped a clinical trial of its cancer drug tivantinib because the therapy was not improving survival in lung cancer patients.
ArQule and its partner Daiichi Sankyo of Japan said they stopped a late-stage study of tivantinib as a treatment for non-small cell lung cancer. The companies said patients who were being treated with tivantinib and Tarceva, another cancer drug, were not living longer than patients treated with Tarceva and a placebo. The trial was designed to compare how long patients lived after treatment with the two drug regimens.
The trial was stopped after a review by a committee of independent monitors. The committee said the study would not show that tivantinib patients were living longer.
Shares of ArQule lost $2.73, or 54.7 percent, to $2.26 in late morning trading. Earlier the stock dropped to $1.98, its lowest price in nearly four years.
Tivantinib is ArQule's most advanced drug, and Tuesday's failure was its second recent setback. In late August, the company's Japanese partner Kyowa Hakko Kirin Co. temporarily suspended enrollment of patients in a separate trial of tivantinib because some patients are believed to have contracted interstitial lung disease, a condition that causes scarring of the lung tissue and impair a patient's ability to breathe.
ArQule stock traded as high as $6.80 in mid-August, before that news.
The Woburn, Mass., company said Tuesday that tivantinib and Tarceva were more effective at stopping the progression of lung cancer than Tarceva alone: patients treated with the two-drug regimen had longer progression-free survival, which means they lived longer before death or the resumption of disease progression, whichever came first. The companies enrolled about 1,000 patients in the trial.
Daiichi Sankyo and ArQule are working together to develop tivantinib in the U.S., Europe, and other regions. Kyowa Hakko Kirin has the right to develop and market the drug in Japan, China, South Korea, and Taiwan.
Tarceva is a pill marketed by Roche of Switzerland. It is approved as a maintenance treatment for non-small cell lung cancer and a secondary treatment for pancreatic cancer.