Biotechnology company Oncothyreon Inc. (ONTY: Quote), revealed details from its ongoing clinical trials of PX-866, a pan-isoform phosphatidylinositol-3-kinase inhibitor, in the treatment of cancer. The details were presented at the American Society of Clinical Oncology annual meet in Chicago.
Oncothyreon's phase 1 trial of PX-866 in combination with chemotherapeutic agent docetaxel - Taxotere, includes 43 patients with advanced cancer for whom docetaxel was considered standard of care. Subjects were treated at three different dose levels of PX-866 administered daily in combination with the standard dose of docetaxel once every three weeks.
No dose-limiting toxicities were identified. The combination of PX-866 and docetaxel was generally well-tolerated. Adverse events were 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, with at least two cycles of therapy and a follow-up tumor assessment. Disease control rate was 85 percent after two cycles of therapy and 58 percent after four cycles. No statistically significant differences in progression-free survival were identified for patients with PIK3CA mutations or PTEN deficiency.
Interim data from an open-label single-arm Phase 2 trial of PX-866 in patients with glioblastoma multiforme - a type of brain cancer, enrolled 17 patients in the first stage of the study. Subjects included patients with brain tumor in first relapse during or following primary therapy.
PX-866 was well-tolerated in the study, with the most common adverse events being diarrhea and reversible liver enzyme elevation. The efficacy data met the pre-specified endpoint, and the trial is currently enrolling a planned additional 15 patients in the second stage.
In its PX-866 phase 2 program, subjects include up to 40 patients with metastatic or recurrent castration resistant prostate cancer who have not received prior chemotherapy. The primary endpoint of this single-arm screening trial is the proportion of patients with lack of disease progression at 12 weeks from the initiation of therapy with PX-866. The trial has completed enrollment in the first stage of the study and the interim analysis is currently pending.
The study of PX-866 in combination with docetaxel has advanced to the Phase 2 portion, an open-label, randomized evaluation of the antitumor activity and safety of PX-866 administered at the recommended daily dose in combination with docetaxel, versus docetaxel alone, in two groups of patients.
Group 1 is enrolling patients with non-small cell lung cancer with second or third line treatment. Group 2 is enrolling patients with locally advanced, recurrent or metastatic squamous cell carcinoma of the head and neck, and having failed prior therapy.
Oncothyreon has also advanced to the Phase 2 portion of a phase 1/2 trial of PX-866 in combination with the chimeric monoclonal antibody cetuximab (Erbitux), evaluating the antitumor activity and safety of PX-866 in combination with cetuximab, versus cetuximab alone, in two groups of patients.
ONTY last traded at $3.51, down $0.12 or 3.31%, on the Nasdaq.
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by RTT Staff Writer
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