FDA Approves Abemaciclib for Certain Patients With HR-Positive, HER2-Negative High Risk Early Breast Cancer

The FDA has granted approval to abemaciclib (Verzenio) in combination with endocrine therapy for the adjuvant treatment of adult patients with hormone receptor (HR)–positive, human epidermal growth factor receptor 2 (HER2)-negative, node-positive, early breast cancer at high risk of recurrence and a Ki-67 score of 20% or higher, as determined by an FDA-approved test. The FDA also approved the Ki-67 IHC MIB-1 pharmDx (Dako Omnis) assay as a companion diagnostic for selecting eligible patients for this indication of abemaciclib.

"Over time, the collective results of the Verzenio clinical development program have demonstrated a differentiated CDK4/6 inhibitor profile, and the landmark data from the monarchE trial that supported this new indication in HR-positive, HER2-negative early breast cancer represent another important step forward for people who are in need of new treatment options," said Jacob Van Naarden, senior vice president, CEO of Loxo Oncology at Lilly and president, Lilly Oncology, in a press release. "We are pleased with this initial approval in the adjuvant setting and as these data continue to mature, we look forward to further opportunities to work with health authorities to expand the use of Verzenio in this setting."

The approval was based on the results of the phase 3 monarchE (NCT03155997) trial, in which abemaciclib was evaluated among patients with HR–positive, HER2-negative, node-positive, resected, early breast cancer with clinical and pathological features consistent with a high risk of disease recurrence. Study participants were randomized 1:1 to receive 2 years of either abemaciclib plus physician’s choice of standard endocrine therapy (ET) or standard ET alone.

The major efficacy outcome measure was invasive disease-free survival (iDFS). Abemaciclib administered in combination with tamoxifen or an aromatase inhibitor (AI) showed a 37% reduction in the risk of breast cancer recurrence or death compared to standard adjuvant ET alone for patients with high risk clinical and pathological features and a Ki-67 score ≥20% (HR: 0.626 [95% CI: 0.49-0.80]), and an absolute benefit in IDFS event rate of 7.1% at 3 years.

Among 2003 patients with a high risk of recurrence and a Ki-67 score of 20% or higher, a statistically significant improvement in iDFS was found following the addition of abemaciclib (HR, 0.626; 95% CI, 0.488-0.803; P = .0042). The 36-month iDFS rate was 86.1% (95% CI, 82.8-88.8) among patients administered abemaciclib plus tamoxifen or an AI and 79.0% (95% CI, 75.3-82.3) in patients administered tamoxifen or an AI. Overall survival data were not mature at the time of the iDFS analysis.

Adverse events (AEs) from monarchE were consistent with the known safety profile for abemaciclib.Among 5591 patients, the most common AEs (>10%) in the abemaciclib plus ET arm, and >2% higher than the ET arm alone, were diarrhea, infections, fatigue, nausea, headache, vomiting, stomatitis, decreased appetite, dizziness, rash, and alopecia.

The recommended starting dose for abemaciclib is 150 mg administered twice daily in combination with tamoxifen or an AI until completion of 2 years of treatment or until disease recurrence or intolerable toxicity.

"The design and results of the monarchE study are practice-changing and represent the first advancement in adjuvant treatment of HR-positive, HER2-negative breast cancer in a very long time," said Sara M. Tolaney, MD, MPH, Harvard Medical School, Dana-Farber Cancer Institute, and investigator on the monarchE study, in a press release. "This FDA approval for Verzenio in combination with endocrine therapy in the early breast cancer setting has the potential to become a new standard of care for this population. We are encouraged by the marked reduction in the risk of recurrence even beyond the two-year treatment period in these patients, and I'm grateful to be able to offer this as a treatment option to my patients."

Reference

FDA Approves Verzenio® (abemaciclib) as the First and Only CDK4/6 Inhibitor for Certain People with HR+ HER2- High Risk Early Breast Cancer. Eli Lilly and Company; 2021. Accessed October 13, 2021. https://investor.lilly.com/news-releases/news-release-details/fda-approves-verzenior-abemaciclib-first-and-only-cdk46