Patients with HR+, HER2–, Early Breast Cancer Experienced Survival Improvement with Verzenio Plus Endocrine Therapy

Patients with hormone receptor–positive, HER2-negative, high-risk early breast cancer experienced improvements in invasive disease-free survival (iDFS) and distant relapse-free survival (DRFS) (the time after treatment until signs or symptoms of breast cancer or another cancer) when treated with Verzenio (abemaciclib) plus endocrine therapy (ET), according to findings from the monarchE trial presented on Friday at the 2023 American Society of Clinical Oncology Annual Meeting in Chicago.

“For patients with hormone receptor–positive, HER2-negative, high-risk, early breast cancer (Verzenio) plus ET showed consistent treatment benefit across age subgroups with clinically meaningful absolute risk reduction in both iDFS as well as DRFS rates observed in both younger and older patients,” study co-author Dr. Erika P. Hamilton, director of breast and gynecologic cancer research at Sarah Cannon Research Institute in Nashville said in a presentation of the data.

Patients 65 and older who received Verzenio plus ET had a four-year iDFS rate of 82%, compared to 76.8% of patients who received ET alone. Among patients who were younger than 65, the four-year iDFS rates were 86.5% of those treated with Verzenio and ET and 79.8% for patients treated with just ET.

Findings from the monarchE trial were previously presented at the 2022 San Antonio Breast Cancer Congress and published earlier this year in the journal Lancet Oncology.

At a median follow-up of 42 months, patients on Verzenio plus ET saw a 34% reduction in the risk of experiencing an iDFS event vs those treated with ET alone, while 48-month iDFS rates were 85.8% and 79.4% with or without Verzenio, respectively. Patients also saw DRFS benefits across age groups, according to the study.

monarchE was a phase 3 trial that randomly assigned 2,791 patients to receive 150 mg of Verzenio twice daily for two years in addition to standard-of-care ET or ET alone.

“The objective of this analysis of monarchE was to explore the efficacy and safety of (Verzenio) and the subgroup of older patients (who) were enrolled,” Hamilton said. “All patients went on to receive three to eight years of standard single-agent ET per patient and physician decision. All patients are off (Verzenio) with a median follow up of 42 months. Efficacy, safety and patient-reported outcome analyses were conducted in two age groups, those patients who were (younger) than 65 years and those that were 65 years or greater. Patients who were (older) than 75 years made up only 3% of the study population, which really precluded a detailed outcome analysis in this subgroup.”

The baseline characteristics for the intention-to-treat population were well balanced with a median age of 51. Baseline factors relevant to this analysis included pathologic tumor size, number of positive lymph nodes, histopathological grade, prior neoadjuvant chemotherapy, and ECOG performance status, which indicates how much a patients disease affects how they can perform their activities of daily living.

Most younger patients had tumor size of 20 mm to less than 50 mm (48%), at least four positive lymph nodes (59%), G2 disease (moderate differences can be seen in cancer cells; 49%), had received neoadjuvant chemotherapy (97%) and an ECOG performance status of 0, indicating that they can perform all their daily tasks with little to no help (86%). Older patients mostly had tumor size of 20 mm to less than 50 mm (57%), four or more positive lymph nodes (64%) and G2 disease (52%). Hamilton called attention to the fact that fewer older patients had neoadjuvant chemotherapy (82%) and ECOG performance status of 0 (77%), which was expected.

“Similarly, in terms of patients who had four or more baseline pre-existing comorbidities, only 33% of our younger patients experienced this (compared with) more than half at 51% of our older patients,” Hamilton said. Further, among treated patients 95% of older patients received aromatase therapy as their initial endocrine therapy, compared with 64% of younger patients, more of whom received tamoxifen.

Side effect rates were similar between age groups, Hamilton noted.

Clinically relevant side effects included diarrhea, fatigue, neutropenia (low white blood cell count), alanine aminotransferase (ALT) increase, which could indicate liver damage, venous thromboembolism (VTE), also known as blood clots and interstitial lung disease (ILD).

Hamilton noted that quality of life was preserved in both age groups during the two-year treatment period.

“These data support the use of (Verzenio) across age groups and can be used to counsel patients about expectations of treatment experience, and also the safety and utilizing dose reductions if needed,” she concluded.

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