The US Food and Drug Administration (FDA) approved abemaciclib with an aromatase inhibitor (AI) for first-line endocrine-based therapy in postmenopausal patients with hormone receptor (HR)-positive, HER2-negative advanced or metastatic breast cancer, according to a press release.1

Abemaciclib — a CDK 4/6 inhibitor — was previously approved for HR-positive, HER2-negative metastatic breast cancer in combination with fulvestrant following disease progression after endocrine therapy, and as monotherapy for HR-positive, HER2-negative advanced or metastatic breast cancer among patients who had failed endocrine and chemotherapy.

The FDA based its approval on findings from the phase 3 MONARCH trial (ClinicalTrials.gov Identifier: NCT02246621), for which researchers randomly assigned 493 postmenopausal women who had not received prior systemic therapy to abemaciclib 150 mg or placebo twice on a daily continuous schedule, plus anastrozole 1 mg or letrozole 2.5 mg daily.

Abemaciclib plus AI significantly improved progression-free survival (PFS), nearly doubling PFS time compared with placebo and AI (28.2 months vs 14.8 months, respectively; hazard ratio [HR], 0.54; 95% CI, 0.418-0.698; P < .0001).

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Patients in the abemaciclib arm also had an objective response rate of 55.4% compared with 40.2% among patients treated with placebo, and the median duration of response was 27.4 months vs 17.5 months among patients treated with abemaciclib vs placebo, respectively.

The most frequently observed grade 3 to 4 adverse events included neutropenia, leukopenia, diarrhea, infections, fatigue, abdominal pain, anemia, nausea, and vomiting.2

Reference

  1. Lilly received additional FDA approval for Verzenio (abemaciclib) as initial treatment for advanced breast cancer [press release]. Indianapolis, IN: Eli Lilly and Company; February 26, 2017. https://www.prnewswire.com/news-releases/lilly-receives-additional-fda-approval-for-verzeniotm-abemaciclib-as-initial-treatment-for-advanced-breast-cancer-300604409.html. Accessed February 27, 2018.
  2. FDA approves abemaciclib as initial therapy for HR-positive, HER2-negative metastatic breast cancer [news release]. Silver Spring, MD: US Food and Drug Administration; February 26, 2018. https://www.fda.gov/Drugs/InformationOnDrugs/ApprovedDrugs/ucm598404.htm. Accessed February 27, 2018.