Dr. Kruse on the Effects of the MAINTAIN Trial on HR+/HER2- Breast Cancer Treatment

Megan Kruse, MD, medical oncologist, Cleveland Clinic, discusses the real-world effects of the phase 2 MAINTAIN trial (NCT02632045) on treatment in advanced hormone receptor (HR)–positive, HER2-negative breast cancer.

The phase 2 trial investigated the continued use of CDK4/6 inhibitors plus hormone therapy in the second-line setting for patients who progressed on prior CDK4/6 inhibition and endocrine therapy. Patients were randomly assigned to fulvestrant (Falsodex) with or without ribociclib (Kisqali).

The sequencing of agents remains challenging in everyday practice, and the MAINTAIN trial sought to address this unmet need, Kruse states. Findings from the MAINTAIN trial demonstrated that the sequential use of CDK4/6 inhibitors improved progression-free survival vs subsequent treatment with endocrine therapy alone in the second line, supporting a strategy that has not been wholly endorsed to date.

Many patients in MAINTAIN previously received palbociclib (Ibrance), and it would be beneficial to see whether the results of the trial hold true in a larger percentage of patients who received ribociclib or abemaciclib (Verzenio) in the first line, Kruse continues. Notably, the results also raise the question of whether second-line ribociclib is making up for the lack of benefit palbociclib may have in the first line, as seen in the phase 3 PALOMA-2 trial (NCT01740427).

Ultimately, the MAINTAIN trial data are hypothesis generating, but they may not be enough to change clinical practice, Kruse notes. This strategy is an option available to patients but continued real-world data will be useful in informing such treatment strategies, Kruse concludes.