SEATTLE, June 2, 2012 /PRNewswire/ - Oncothyreon Inc. (Nasdaq: ONTY) today announced that data from two clinical trials of PX-866, a pan-isoform phosphatidylinositol-3-kinase (PI-3K) inhibitor, were presented today at the American Society of Clinical Oncology (ASCO) meeting in Chicago. Oncothyreon also provided an update on the status of its ongoing Phase 2 development program for PX-866.
Phase 1 Trial of PX-866 in Combination with Docetaxel
Data from the Phase 1 portion of the ongoing Phase 1/2 of PX-866 in combination with the chemotherapeutic agent docetaxel (Taxotere®) were presented by Antonio Jimeno, M.D., Ph.D., of the University of Colorado Cancer Center, Aurora, Colorado. The trial enrolled 43 patients with advanced cancer for whom docetaxel was considered standard of care. Patients were treated at three different dose levels of PX-866 administered daily in combination with the standard dose of docetaxel (75 mg/m 2) administered once every three weeks. No dose-limiting toxicities were identified, and the recommended Phase 2 daily dose of PX-866 to be given in combination with docetaxel was determined to be the same as the single agent daily maximum tolerated dose of 8 mg.
The combination of PX-866 and docetaxel was generally well-tolerated, with most adverse events being mild to moderate in severity. The safety profile for combination treatment was consistent with that for either drug administered alone. Combination treatment had no impact on the pharmacokinetic profile of either drug.Thirty-three patients were evaluable for response, defined as having undergone at least two cycles of therapy and a follow-up tumor assessment. In these patients, the disease control rate (partial response or stable disease) was 85 percent (28/33) after two cycles of therapy and 58 percent (19/33) after four cycles. Ten patients were on study for more than 200 days, five of whom remained on therapy at the time of the report. Nine patients with stable disease or better discontinued docetaxel after four or more cycles and continued on single agent PX-866, including all five remaining on therapy. No statistically significant differences in progression-free survival were identified for patients with PIK3CA mutations or PTEN deficiency.