Oncothyreon commences combination PX-866/cetuximab Phase 1/2 trial in cancers

Oncothyreon Inc. (Nasdaq: ONTY) today announced enrollment of the first patient in a Phase 1/2 trial of PX-866 in combination with the chimeric monoclonal antibody cetuximab (Erbitux®). PX-866 is a small molecule compound designed to inhibit the activity of phosphatidylinositol-3-kinase (PI-3K), a component of an important cell survival signaling pathway.

The primary objective of the Phase 1 dose-escalation portion of the trial is to determine the maximum tolerated or recommended daily dose of PX-866 to be given in combination with the standard dose of cetuximab administered weekly to patients with either progressive metastatic colorectal carcinoma (CRC) or progressive, recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN). The Phase 2 portion is designed as a screening trial and will be an open-label, randomized evaluation of the antitumor activity and safety of PX-866 administered at the maximum tolerated or recommended dose in combination with cetuximab, versus cetuximab alone, in two groups of patients not previously treated with cetuximab.  Group 1 will enroll patients with metastatic CRC who have a history of progression or recurrence following prior treatment with irinotecan and oxaliplatin containing regimens or who are intolerant of irinotecan.  Patients with CRC and Kras mutations are excluded from the trial. Group 2 will enroll patients with progressive, recurrent or metastatic SCCHN. The two groups will be randomized and evaluated independently.

The primary endpoint of the Phase 1 portion of the trial is safety, and will enroll up to a total of 18 patients at three different dose levels of PX-866 in combination with cetuximab.  Up to 144 patients may be enrolled in the Phase 2 portion of the study, including 72 (36 per arm) in each group. The primary endpoint of the Phase 2 portion is objective response rate based on RECIST criteria. Secondary endpoints include progression free and overall survival, duration of response and disease control rate. Additional information is available through clinicaltrials.gov.

"We are delighted to have initiated this second of four planned Phase 1/2 and Phase 2 trials of PX-866," said Robert L. Kirkman, M.D., President and CEO of Oncothyreon. "As previously indicated, we are committed to a broad Phase 2 development program for PX-866, in combination with other agents, as a single agent, and in multiple tumor types, to maximize our opportunity to demonstrate the utility of this novel, irreversible PI-3K inhibitor."