On June 05, 2016 Oncothyreon Inc. (NASDAQ:ONTY), a clinical-stage biopharmaceutical company, reported 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) (Free ASCO Whitepaper) (Press release, Oncothyreon, JUN 5, 2016, View Source [SID:1234513013]). ONT-380 is a highly selective small molecule HER2 inhibitor being developed in combination to treat HER2+ advanced or metastatic breast cancer.

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

                  Schedule Your 30 min Free Demo!

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.