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Oncothyreon Presents Phase 1b Results of ONT-380 in Combination with T-DM1 in HER2+ Metastatic Breast Cancer at ASCO

CHICAGO, June 05, 2016 (GLOBE NEWSWIRE) -- Oncothyreon Inc. (NASDAQ:ONTY), a clinical-stage biopharmaceutical company, today announced the presentation of clinical data on its lead product candidate, ONT-380, at the 52nd Annual Meeting of the American Society of Clinical Oncology (ASCO). ONT-380 is a highly selective small molecule HER2 inhibitor being developed in combination to treat HER2+ advanced or metastatic breast cancer.

Data from a poster presentation (#513 “Efficacy Results of a Phase 1b Study of ONT-380, a CNS-Penetrant TKI, in Combination with T-DM1 in HER2+ Metastatic Breast Cancer (MBC), Including Patients with Brain Metastases”) showed promising safety and efficacy results in a Phase 1b study as treatment in patients with progressive disease who were previously treated with trastuzumab and a taxane.

“These results continue to demonstrate the potential of ONT-380 in the treatment of HER2+ breast cancer,” said Luke Walker, M.D., Vice President, Clinical Development. “The early evidence of systemic activity, combined with a favorable safety profile and encouraging activity against brain metastases, is supportive of further development of this combination.”

“Our internal team and advisors believe that these data are very intriguing and that the T-DM1 combination warrants further exploration,” commented Scott Myers, President and CEO. “However, given current resources and the development requirements in this setting, we will pursue this combination in cooperation with others or develop ourselves at a later date. Going forward, we remain focused on advancing our ongoing Phase 2 ‘Triplet’ trial with ONT-380 in combination with capecitabine and trastuzumab.”

Updated data from the ongoing “Triplet” Phase 1b trial and the future ONT-380 product development plan will be presented at the Company’s R&D Day on June 14th in New York City.

Summary of Results

The Phase 1b study evaluated ONT-380, an orally bioavailable, highly potent HER2 selective tyrosine kinase inhibitor, in patients with HER2+ metastatic breast cancer previously treated with trastuzumab and a taxane. The study included patients with brain metastases. The data showed:

Activity

  • Median progression-free survival (PFS) was 8.2 months.
  • In 34 patients with measurable disease evaluable per RECIST 1.1, an overall response rate of 47% was achieved. Best responses in patients were:
    • One patient with a complete response and 15 patients with partial responses.
    • 14 (41%) with stable disease, and four patients (12%) with progressive disease.

Safety

  • The majority of adverse events (AE) were Grade 1.
  • Most patients requiring a dose reduction of ONT-380 maintained disease control at the lower dose.

Brain metastases

  • Many of the patients with brain metastases in the study had long-term control of both brain metastases and systemic disease.
  • Progression-free survival in the 30 patients with brain metastases was similar to patients without brain metastases.
  • There were no patients without brain metastases at baseline who developed new clinically apparent brain metastases while on the study.

About Oncothyreon

Oncothyreon is a clinical-stage biopharmaceutical company specializing in the development of innovative therapeutic products for the treatment of cancer. Our goal is to discover, develop and commercialize novel compounds that have the potential to improve the lives and outcomes of cancer patients. Our most advanced product candidate is ONT-380, an orally active and selective small molecule HER2 inhibitor. For more information, visit www.oncothyreon.com.

Forward-Looking Statements

In order to provide Oncothyreon's investors with an understanding of its current results and future prospects, this release contains statements that are forward-looking. Any statements contained in this press release that are not statements of historical fact may be deemed to be forward-looking statements. Words such as "believes," "anticipates," "plans," "expects," "will," "intends," "potential," "possible" and similar expressions are intended to identify forward-looking statements. These forward-looking statements include Oncothyreon's expectations regarding clinical and preclinical development activities, potential benefits of its current and future product candidates, future expenses and the use and adequacy of cash resources.

Forward-looking statements involve risks and uncertainties related to Oncothyreon's business and the general economic environment, many of which are beyond its control. These risks, uncertainties and other factors could cause Oncothyreon's actual results to differ materially from those projected in forward-looking statements, including the risks associated with the costs and expenses of developing its product candidates, the adequacy of financing and cash, cash equivalents and investments, changes in general accounting policies, general economic factors, achievement of the results it anticipates from its preclinical development and clinical trials of its product candidates and its ability to adequately obtain and protect its intellectual property rights. Although Oncothyreon believes that the 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 Oncothyreon's risks and uncertainties, you are encouraged to review the documents filed with the securities regulators in the United States on EDGAR and in Canada on SEDAR. Except as required by law, Oncothyreon does not undertake any obligation to publicly update its forward-looking statements based on events or circumstances after the date hereof.

Additional Information

Additional information relating to Oncothyreon can be found on EDGAR at www.sec.gov and on SEDAR at www.sedar.com.

Investor Contact: Julie Rathbun Rathbun Communications 206-769-9219 ir@oncothyreon.com Tricia Truehart The Trout Group 646-378-2953 ttruehart@troutgroup.com Media Contact: Brad Miles BMC Communications 646-513-3125 bmiles@bmccommunications.com

Source:Oncothyreon Inc.