NEW YORK (AP) -- Shares of ArQule Inc. plunged Wednesday after the company said one of its partners has stopped enrolling patients in a clinical trial of its cancer drug tivantinib.
THE SPARK: ArQule's Japanese partner Kyowa Hakko Kirin Co. temporarily suspended enrollment of patients in a late-stage trial of tivantinib as a treatment for lung cancer. Kyowa made the decision on a recommendation from a safety monitoring committee because some patients are believed to have contracted interstitial lung disease.
Interstitial lung disease is a group of conditions that cause scarring of the lung tissue and impair a patient's ability to breathe. The Mayo Clinic says the scarring is generally irreversible.
ArQule disclosed the stoppage in a form filed with the Securities and Exchange Commission Wednesday. It said Kyowa Hakko Kirin is still treating patients who had already enrolled in the study.
THE BIG PICTURE: Tivantinib is designed to block a molecule that is involved in cancer cell growth, blood vessel formation, survival, and metastasis. It is also being studied as a treatment for liver cancer and other forms of the disease in addition to lung cancer.
Kyowa Hakko Kirin has the rights to market the drug in Japan and some other Asian countries, and Daiichi Sankyo, another Japanese drug company, has the rights to market the drug in the U.S., Europe, South America, and other regions.
In January, ArQule and Daiichi Sankyo said tivantinib delayed the progression of hepatocellular carcinoma, the most common type of primary liver cancer, by 56 percent compared to a placebo.
Tivantinib is ArQule's most advanced drug candidate. The Woburn, Mass., company has three other drugs in early-stage clinical testing.
SHARE ACTION: ArQule shares sank $1.31, or 19.6 percent, to $5.39 in afternoon trading. Earlier the stock dropped 28 percent to $4.81. Before the start of trading on Wednesday, ArQule stock was down 19.5 percent from its annual high of $8.32.