A small early-stage trial of Ariad Pharmaceuticals Inc's experimental pill AP26113 showed it shrank tumors in eight out of 11 lung cancer patients with a genetic mutation in a gene known as ALK.
The drug, called '113 for short, is being tested in patients with non-small cell lung cancer who test positive for the abnormal ALK gene, as well as those with a specific mutation in a gene known as EGFR.
Thirty-four patients have been enrolled in the Phase 1/2 trial, which is designed to determine the ideal dosage for later-stage trials.
Initial findings show that of 11 ALK-positive patients evaluated at five dose levels, eight had partial tumor shrinkage.
Two patients within that group had not been previously treated with Xalkori, the Pfizer Inc drug that also targets the ALK mutation and researchers said both of them experienced tumor shrinkage.
The study also evaluated six EGFR patients who had stopped responding to Tarceva, the lung cancer drug sold by Roche Holding AG. One of them achieved partial tumor shrinkage, two were stable and three had their cancer worsen, according to Ariad.
The trial update is scheduled for presentation on Saturday at a cancer conference in Vienna.
Ariad said 19 patients remain in the study, with 16 of them at the highest dose.
Side effects of '113 included fatigue, nausea and diarrhea, but one high-dose patient had elevated live enzymes, a signal of liver toxicity.
Ariad Chief Executive Harvey Berger said the company plans to launch the Phase 2 portion of the trial before the end of this year.
"Our ultimate goal in development of '113 will be to apply it first to ALK, then EGFR in those patients who have become resistant or intolerant to available therapies," he said.
About 4 percent of patients with non-small cell lung cancer, the most common type of the disease, have the targeted ALK mutation, while EGFR mutations occur in around 15 percent of them.
(Reporting By Deena Beasley in Los Angeles. Editing by Andre Grenon)