LOS ANGELES--(BUSINESS WIRE)--

Puma Biotechnology, Inc. (Nasdaq: PBYI), a biopharmaceutical company, announced that interim results from the Phase Ib/II FB-10 clinical trial of Puma’s investigational drug PB272 (neratinib) given in combination with the antibody drug conjugate T-DM1 (Kadcyla, ado-trastuzumab emtansine) were presented at the 2017 American Association for Cancer Research Annual Meeting (AACR) that is currently taking place in Washington, D.C. The presentation entitled, “NSABP FB-10: Phase Ib dose-escalation study evaluating trastuzumab emtansine (T-DM1) with neratinib in women with metastatic HER2-positive breast cancer” was selected for an oral presentation.

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A waterfall plot showing "% Change in Size of Target Lesions" from Puma Biotechnology's FB-10 Trial in HER2-positive metastatic breast cancer is attached. (Graphic: Business Wire)

The trial enrolled patients with HER2-positive metastatic breast cancer who had previously been treated with chemotherapy and the combination of trastuzumab (Herceptin) and pertuzumab (Perjeta). Study treatment consisted of the standard dose of T-DM1 at 3.6 mg/kg administered intravenously every 3 weeks and neratinib administered orally at escalating doses of 120, 160, 200 and 240 mg per day continuously. Primary diarrhea prophylaxis with high dose loperamide was administered.

For the 16 patients who were evaluable for efficacy, the objective response (CR/PR) rate was 56%. More specifically, the efficacy results from the trial demonstrated that 3 patients had a complete response (CR) lasting 17.1 months, 11.9 months and 12+ months; 6 patients had a partial response (PR); 3 patients had stable disease (SD); and 4 patients had progressive disease (PD). The number and types of response per dose cohort are summarized in the table below.

The waterfall plot for the trial, % Change in Size of Target Lesions,” is shown in Figure 1, which is attached to this news release. In addition, the slides from the presentation are available on the Puma Biotechnology website.

The safety results of the study showed that the most frequently observed grade 3 adverse events were diarrhea, nausea, thrombocytopenia and hypertension. More specifically, for the 21 patients with available safety assessments, grade 3 diarrhea was reported in 4 patients (19%), grade 3 nausea was reported in 3 patients (14%), grade 3 thrombocytopenia was reported in 3 patients (14%), and grade 3 hypertension was reported in 2 patients (10%). There was 1 dose limiting toxicity (DLT) at the 120 mg dose (1 of 6 patients), 3 DLTs at the 200 mg dose (3 of 8) and 2 DLTs at the 240 mg dose (2 of 3). Additional patients are currently being accrued at the 160 mg dose in order to define the recommended Phase II dose.

Dr. Jame Abraham, Director of the Breast Oncology Program at Taussig Cancer Institute, Professor of Medicine at Cleveland Clinic, and principal investigator of the study, said, “We are encouraged by these initial findings and we will continue to enroll patients at the 160 mg dose to further evaluate the impact in this patient population.”

Alan H. Auerbach, Chief Executive Officer and President of Puma Biotechnology, said, “We are pleased to see the high response rate of the combination of T-DM1 and neratinib in this patient population who were previously treated with both pertuzumab and trastuzumab in this study. We look forward to completing enrollment in the current cohort and moving this combination into Phase II trials.”

About Puma Biotechnology

Puma Biotechnology, Inc. is a biopharmaceutical company with a focus on the development and commercialization of innovative products to enhance cancer care. The Company in-licenses the global development and commercialization rights to three drug candidates—PB272 (neratinib (oral)), PB272 (neratinib (intravenous)) and PB357. Neratinib is a potent irreversible tyrosine kinase inhibitor that blocks signal transduction through the epidermal growth factor receptors, HER1, HER2 and HER4. Currently, the Company is primarily focused on the development of the oral version of neratinib, and its most advanced drug candidates are directed at the treatment of HER2-positive breast cancer. The Company believes that neratinib has clinical application in the treatment of several other cancers as well, including non-small cell lung cancer and other tumor types that over-express or have a mutation in HER2. Further information about Puma Biotechnology can be found at www.pumabiotechnology.com.

Forward-Looking Statements:

This press release contains forward-looking statements, including statements regarding the development of the Company’s drug candidates. All forward-looking statements included in this press release involve risks and uncertainties that could cause the Company's actual results to differ materially from the anticipated results and expectations expressed in these forward-looking statements. These statements are based on current expectations, forecasts and assumptions, and actual outcomes and results could differ materially from these statements due to a number of factors, which include, but are not limited to, the fact that the Company has no product revenue and no products approved for marketing; the Company's dependence on PB272, which is still under development and may never receive regulatory approval; the challenges associated with conducting and enrolling clinical trials; the risk that the results of clinical trials may not support the Company's drug candidate claims; even if approved, the risk that physicians and patients may not accept or use the Company's products; the Company's reliance on third parties to conduct its clinical trials and to formulate and manufacture its drug candidates; the Company's dependence on licensed intellectual property; and the other risk factors disclosed in the periodic and current reports filed by the Company with the Securities and Exchange Commission from time to time, including the Company's Annual Report on Form 10-K for the year ended December 31, 2016. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. The Company assumes no obligation to update these forward-looking statements, except as required by law.

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