Abstract P3-14-01: Effects of adding budesonide or colestipol to loperamide prophylaxis on neratinib-associated diarrhea in patients with HER2+ early-stage breast cancer: The CONTROL trial

Background: Neratinib is an irreversible pan-HER tyrosine kinase inhibitor. Results from the randomized, placebo-controlled, Phase III ExteNET study demonstrated that neratinib significantly improves 24-month iDFS in patients (pts) with trastuzumab-treated early-stage HER2+ breast cancer (HR 0.67; 95% CI 0.50–0.91; p=0.009) [Chan et al. Lancet Oncol 2016]. In ExteNET, loperamide prophylaxis was not mandated, and diarrhea was the most commonly observed toxicity (grade 3, 39.8%). To reduce neratinib-associated diarrhea, high-dose loperamide prophylaxis given with the first 1–2 cycles of neratinib has been incorporated into all neratinib clinical trials; available data suggest that loperamide prophylaxis reduces the incidence and median cumulative duration of higher-grade neratinib-related diarrhea. CONTROL is an international, open-label, sequential cohort, phase II study investigating the effects of prophylaxis with loperamide ± the long-acting corticosteroid budesonide or bile acid sequestrant colestipol on neratinib-associated diarrhea. We present updated data from this study. Methods: Pts with stage 1–3c HER2+ breast cancer who completed trastuzumab-based adjuvant therapy within 1 year were eligible. All pts received oral neratinib 240 mg once daily for 1 year + oral loperamide prophylaxis for 1 or 2 cycles (1 cycle = 28 days) ± budesonide or colestipol for the first cycle (see table). Adverse events were graded according to NCI-CTCAE (v4.0). Primary endpoint: incidence of grade ≥3 diarrhea. Results: Conclusions: A structured loperamide prophylactic regimen for 1 or 2 cycles reduces the incidence, severity and duration of neratinib-associated diarrhea compared with events observed in the ExteNET trial. Adding budesonide or colestipol appears to further diminish the duration and number of episodes of diarrhea and improves neratinib tolerability. Final analysis of the CONTROL study will be performed when all pts have completed 12 months of neratinib therapy. Updated data will be available at the meeting. Clinicaltrials.gov: NCT02400476. Citation Format: Hurvitz S, Chan A, Iannotti N, Ibrahim E, Chien J, Chan N, Kellum A, Hansen V, Marx G, Kendall SD, Wilkinson M, Castrellon A, Ruiz R, Fang P, Hunt D, Moran S, Olek E, Barcenas CH, Rugo HS. Effects of adding budesonide or colestipol to loperamide prophylaxis on neratinib-associated diarrhea in patients with HER2+ early-stage breast cancer: The CONTROL trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-14-01.