Oncothyreon Initiates Phase 1/2 Trial of its PI-3 Kinase Inhibitor PX-866 in Combination with Cetuximab

SEATTLE, WA, Dec. 20 /CNW/ - 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."

About PX-866

PX-866 is an inhibitor of the PI-3K/PTEN/AKT pathway, a critical cell signaling pathway that is activated in many types of human cancer. Aberrant activation and regulation of PI-3K is implicated in a large proportion of human cancers, where it leads to increased proliferation and inhibition of apoptosis (programmed cell death). Results from a single-agent Phase 1 open-label, dose escalation study of PX-866 in patients with advanced metastatic cancer presented at the American Society of Clinical Oncology earlier this year demonstrated that PX-866 was well tolerated using both an intermittent and continuous (daily) dosing schedule.   Additional data from the Phase 1 trial presented at the EORTC/NCI/AACR meeting in Berlin on November 18, 2010 demonstrated that 8 of 19 evaluable patients treated with continuous dosing achieved stable disease as their best response.

About Oncothyreon

Oncothyreon is a biotechnology company specializing in the development of innovative therapeutic products for the treatment of cancer. Oncothyreon's goal is to develop and commercialize novel synthetic vaccines and targeted small molecules that have the potential to improve the lives and outcomes of cancer patients. For more information, visit www.oncothyreon.com.

Forward Looking Statements

In order to provide Oncothyreon's investors with an understanding of its current intentions and future prospects, this release contains statements that are forward looking, including statements related to future preclinical and clinical development plans for our product candidates. These forward-looking statements represent Oncothyreon's intentions, plans, expectations and beliefs and are based on its management's experience and assessment of historical and future trends and the application of key assumptions relating to future events and circumstances.

Forward-looking statements involve risks and uncertainties, including risks and uncertainties related to Oncothyreon's business and the general economic environment. Many of these risks and uncertainties are beyond Oncothyreon's control. These risks, uncertainties and other factors could cause our actual results to differ materially from those projected in forward-looking statements. Risks, uncertainties, and assumptions include those predicting the timing, duration and results of clinical trials, the timing and results of regulatory reviews, the safety and efficacy of our product candidates, and the indications for which our product candidates might be developed. There can be no guarantee that the results of preclinical studies or clinical trials will be predictive of either safety or efficacy in future clinical trials. These and other risks and uncertainties are described in the reports and other documents filed by Oncothyreon Inc. with the SEC and/or Canadian regulatory authorities.

Although Oncothyreon believes that any forward-looking statements contained herein are reasonable, it can give no assurance that its expectations are correct. All forward-looking statements are expressly qualified in their entirety by this cautionary statement. For a detailed description of the risks and uncertainties associated with Oncothyreon, you are encouraged to review the official corporate documents filed with the securities regulators in the United States on U.S. EDGAR and in Canada on SEDAR. Oncothyreon is under no obligation to (and expressly disclaims any such obligation to) update or alter its forward-looking statements whether as a result of new information, future events, or otherwise.

Investor and Media Relations Contact:
Julie Rathbun
Rathbun Communications
206-769-9219
[email protected]