Puma Biotechnology Presents Interim Results of Phase Ib/II FB-10 Trial of PB272 in Combination with Trastuzumab Emtansine (T-DM1) in HER2-Positive Metastatic Breast Cancer at the 2017 AACR Annual Meeting

On April 2, 2016 Puma Biotechnology, Inc. (Nasdaq: PBYI), a biopharmaceutical company, reported 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 (AACR) (Free AACR Whitepaper) Annual Meeting (AACR) (Free AACR Whitepaper) that is currently taking place in Washington, D.C (Press release, Puma Biotechnology, APR 2, 2017, View Source [SID1234518392]). 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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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.


Neratinib Dose
(mg/day)
No. of Objective Responses (CR/PR)
/ No. of Evaluable (CR/PR/SD/PD)
120 5/5 (CR 2, PR 3)
160 2/4 (CR 1, PR 1, PD 2)
200 1/5 (PR 1, SD 2, PD 2)
240 1/2 (PR 1, SD 1)

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."