CAMBRIDGE, Mass. ( TheStreet) --An oral cancer drug from Ariad Pharmaceuticals ( ARIA) helped patients with soft tissue and bone cancer remain in remission longer than a placebo, according to results from a phase III study released Tuesday. The Ariad drug, ridaforolimus, is being jointly developed by Merck ( MRK), which plans to file for approval later this year based on positive data from Tuesday's study. The "Succeed" study enrolled 711 patients with soft-tissue or bone sarcoma who responded to previous treatment with chemotherapy. Patients were then treated with daily ridaforolimus or a placebo to determine whether the former could extend the time before the patients' tumors started to grow again. Based on a full, independent analysis of the study, patients treated with ridaforolimus reported a 28% reduction in risk of cancer progression compared to patients treated with a placebo. The result was highly statistically significant, achieving the primary endpoint of the study. At the median, ridaforolimus' benefit was more modest, demonstrating a 3.1-week benefit in progression-free survival over placebo (17.7 weeks compared to 14.6 weeks.) The most common side effects of ridaforolimus observed in the study stomatitis (mouth sores), fatigue, diarrhea and thrombocytopenia. Patients in the study are still be followed to determine, in part, whether ridaforolimus can help sarcoma patients live longer. The study was conducted under a Special Protocol Agreement with FDA that allows the company to seek approval based on the positive disease-progression endpoint. Ariad shares were up 36% to $7.16 in pre-market trading. --Written by Adam Feuerstein in Boston. >To contact the writer of this article, click here: Adam Feuerstein. >To follow the writer on Twitter, go to http://twitter.com/adamfeuerstein. >To submit a news tip, send an email to: email@example.com.