ArQule colorectal cancer drug misses study goal

WOBURN, Mass. (AP) -- Drug developer ArQule Inc. and Japan's Daiichi Sankyo Co. said Friday that their experimental colorectal cancer drug did not meet the main goal for survival without tumor growth in a mid-stage patient study.

ArQule shares were down 15 percent, or 44 cents, at $2.48 on the news in afternoon trading.

Preliminary results of the study of tivantinib, in patients with colorectal cancer that had relapsed or didn't respond to prior treatment, found that the drug appeared to delay tumor growth only slightly.

Patients getting tivantinib in addition to two standard cancer drugs, irinotecan and cetuximab, on average had tumors resume growth after 8.3 months. A comparison patient group getting just the two standard drugs and a placebo had tumor growth, or progression, after 7.3 months on average.

However, both those progression-free periods were longer than expected, based on previous published studies, the companies said. They plan to present detailed results from their study at a future medical meeting.

The study included 122 patients in the U.S., Russia and Western Europe with inoperable colorectal cancer that didn't respond to initial treatment and whose tumors had a particular genetic variation. Side effects were similar in the two patient groups, except that more of the patients getting tivantinib had neutropenia, an abnormally low level of infection-fighting white blood cells called neutrophils.

"We are encouraged by these findings," said Reinhard von Roemeling, Daiichi's head of clinical development for cancer treatments. "We plan to continue discussions . to determine how best to proceed with further clinical development of tivantinib in this tumor type."

ArQule, based in Woburn, Mass., is a biotechnology company trying to develop next-generation cancer pills. Its partner on tivantinib, Tokyo-based Daiichi Sankyo, conducted the study.

The drug works by blocking an enzyme that, when inappropriately activated, can cause cancer cells to grow, spread and live longer.

Colorectal cancer is the No. 2 cause of cancer-related deaths in the U.S., with about 52,000 deaths and more than 140,000 new cases each year, according to the National Cancer Institute.