Characterization of Interchanging Incretin Analogs in Clinical Practice: A Descriptive Report

To characterize the tolerability associated with incretin analog interchanges to equipotent or higher strengths based on an interchange process in an adult outpatient setting.

This was a retrospective chart review of adult patients receiving care through a participating family medicine or endocrinology clinic between January 1, 2022, and November 30, 2022 at a major academic medical center. An incretin analog equivalency table and protocol for interchange was created in response to ongoing shortages and need for therapy adjustments to different medications within the same class. Patients were included if a recommended incretin analog interchange was initiated and a tolerability assessment was conducted. Patients were excluded if they did not meet inclusion criteria or if they were unreachable for tolerability assessments for interchanged agents.

There were 156 patients included for characterization and response to tolerability of interchange. It was determined that 96% of patients tolerated the incretin analog interchange. A dose escalation occurred in 58% of patients, 41% were transitioned to an equipotent dose, and a dose decrease was considered in 1 patient. Prior authorizations were required 74% of the time for the new therapy. The most common interchanges were dulaglutide 4.5 mg to tirzepatide 7.5 mg, dulaglutide 4.5 mg to tirzepatide 10 mg, and dulaglutide 3 mg to tirzepatide 7.5 mg. These interchanges made up 37.3% of the total population and were observed to have 93% tolerability. Seven patients did not tolerate incretin analog interchange. Five experienced gastrointestinal effects and 2 experienced injection site reactions. The interchange of incretin analog was estimated to reduce time to maximum dose by a median of 3 months. During this study, no patients experienced interruption of therapy defined as missing a dose of incretin analog.

This characterization report demonstrates an effective approach to addressing incretin analog interchanges. A high level of tolerability is evident with the defined interchange process. Future studies should continue to confirm effective and safe interchanges of incretin analogs from outcomes and tolerability reports.