#ASCO21: Puma Bio Presents Data Comparing Findings from Phase II CONTROL Trial with Neratinib Arm of Phase III ExteNET Trial

 Dose escalation of neratinib lowers the frequency of severe diarrhea and improves overall tolerability in patients with HER2-positive early stage breast cancer

 

Puma Biotechnology, Inc. (Nasdaq: PBYI), a biopharmaceutical company, presented results at the virtual 2021 ASCO Annual Meeting comparing the diarrhea mitigation strategies investigated in the Phase II CONTROL trial with the neratinib treatment arm of the ExteNET trial where diarrhea prophylaxis was not required. The presentation, entitled “Dose escalation for mitigating diarrhea: Ranked tolerability assessment of antidiarrheal regimens in patients receiving neratinib for early-stage breast cancer,” is included in the Breast Cancer—Local/Regional/Adjuvant Poster Session (#536).

The CONTROL trial is an international, open-label, Phase II study investigating the use of antidiarrheal prophylaxis or dose escalation to improve the tolerability of neratinib-associated diarrhea. The primary endpoint of the trial is the incidence of grade 3 diarrhea. Patients ≥18 years of age with stage I–IIIc HER2-positive breast cancer received neratinib (240 mg/day orally for 1 year) together with one of the regimens investigated: loperamide alone, in combination with budesonide or colestipol, or neratinib dose escalation (DE): 120 mg/day on days 1–7, 160 mg/day on days 8–14, then 240 mg/day thereafter + loperamide PRN.

In the analysis presented at ASCO 2021, five CONTROL cohorts that had completed follow up were evaluated for 13 endpoints related to tolerability. The DE cohort ranked the best among the CONTROL cohorts and was then compared with the neratinib arm of the ExteNET trial, which included patients ≥18 years of age with stage I–III HER2-positive breast cancer receiving neratinib 240 mg/day or matching placebo for one year, without mandated anti-diarrheal treatment. ExteNET was a multicenter, randomized, double-blind, Phase III trial (NCT00878709) of 2,840 HER2-positive early stage breast cancer patients who received neratinib after neoadjuvant and/or adjuvant therapy with chemotherapy and a trastuzumab-based regimen.

Comparison of the CONTROL DE cohort with the ExteNET neratinib arm demonstrated that grade 3 diarrhea was substantially lower in CONTROL DE compared to ExteNET (13.3% vs. 39.9%). Neratinib DE also resulted in fewer total days of grade 3 diarrhea compared to ExteNET (2.5 days vs 5 days). Dose escalation also led to fewer discontinuations due to diarrhea in the first three months of treatment compared to ExteNET (3.3% vs 14.5%). Additionally, the average duration of treatment with neratinib was much longer in the DE cohort versus ExteNET. Overall, the findings of this analysis suggest that escalating the dose of neratinib in the first 2 weeks of treatment may help patients stay on neratinib longer, allowing them the opportunity to complete the recommended 1-year of treatment.

https://www.biospace.com/article/releases/puma-biotechnology-presents-data-comparing-findings-from-the-phase-ii-control-trial-with-the-neratinib-arm-of-the-phase-iii-extenet-trial-at-the-asco-2021-annual-meeting/