Adherence to abemaciclib in patients receiving antidiarrheal medicine.

Abstract

e13016 Background: According to the National Cancer Institute, breast cancer is the most common form of cancer in the United States. Nearly 75% of patients with breast cancer have tumors that are hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative. In 2017, the U.S. Food and Drug Administration (FDA) approved abemaciclib to treat adult patients who have HR+ and HER2- advanced or metastatic breast cancer. While the adverse events associated with abemaciclib have been well documented in clinical trials, it is unknown if adverse events, specifically diarrhea, impact adherence. The purpose of this study is to determine whether adherence to abemaciclib differs for patients who receive loperamide in welcome kits versus those who do not receive loperamide in welcome kits. Methods: This is a retrospective study of patients throughout the United States with HR+, HER2- breast cancer who received abemaciclib from a large specialty pharmacy from July 1, 2018 to December 31, 2019. Patients who received welcome kits (each welcome kit contains three boxes, each box contains ten 2mg tablets of loperamide) served as the intervention group; patients who did not receive welcome kits served as the standard of care group. Baseline characteristics of patients in each group were compared with t-tests for continuous data and the chi square test for categorical data. Medication possession ratio (MPR), dose reduction and dose omission rates in the first three months of taking abemaciclib were compared. Results: We identified 1,180 breast cancer patients who received abemaciclib. The intervention group had 317 patients, with an average age of 60.1 y (SD = 12.0); the control group had 863 members, with an average age of 58.7 y (SD = 11.8). Baseline characteristics did not differ significantly between groups, except for geography (p<0.001), as seen in the table. There was no significant difference (p = 0.858) in mean MPR between the intervention and standard of care groups. There were no significant differences in dose reduction rates (p= 0.390) and dose omission rates (p = 0.872) within three months of starting abemaciclib. Conclusions: Our findings suggest that patients who receive loperamide in welcome kits do not have better adherence to abemaciclib therapy. In this study, both groups showed high adherence to therapy, suggesting that the standard of care group manages diarrhea just as effectively as the intervention group. A welcome kit with loperamide did not impact a patient’s adherence to abemaciclib therapy.[Table: see text]