Randomized phase III trial evaluating motivational interviewing and text interventions to optimize adherence to breast cancer endocrine therapy (Alliance A191901): the GETSET protocol

Background: Hormone receptor-positive (HR +) breast cancer is the most common type of breast cancer in the USA but has excellent long-term outcomes in recent decades, in part due to effective oral endocrine therapy (ET). ET medications are typically prescribed for 5 to 10 years, depending on the risk of recurrence, and must be taken daily. One limiting factor to ET efficacy is nonadherence, with high-risk groups for nonadherence including younger women and Black women. Methods: The Alliance for Clinical Trials in Oncology (Alliance) trial A191901 is an ongoing, four-arm (text message reminder (TMR), motivational interviewing (MI), TMR plus MI, or enhanced usual care) randomized clinical trial that tests the efficacy and effect of two interventions (TMR and/or MI) on improved ET adherence, patient-reported outcomes (PROs), and resource use requirements among HR + breast cancer survivors. Participants are randomized in a 1:1:1:1 ratio to the four arms. With an assumed loss to follow-up of approximately 11%, we plan to recruit 1180 participants. Randomization is stratified based on age and race to ensure balance between the arms, and we oversample younger and Black women, with each group representing 30% of the study population. Participants randomized to an intervention will actively participate in the intervention for 9 months, and all participants will be followed for adherence data and PRO endpoints, through the use of the Pillsy cap medication event monitoring system and Alliance ePRO survey app (i.e., Patient Cloud). The primary analysis will compare Pillsy-measured ET adherence among study arms at 12 months. Discussion: This multisite study will not only define strategies to improve adherence to breast cancer oral therapies, but it will also potentially support strategies in large cooperative research groups that can increase delivery and tolerability of ET, involve diverse patient populations in clinical research, and engage patients effectively in interventional studies, using remote and cost-effective delivery methods. Trial registration: Clinicaltrials.gov NCT04379570 . Registered on 7 May 2020.