The first CDK4/6 inhibitor to get the nod for adjuvant breast cancer Tx

The FDA approved abemaciclib (Verzenio), in combination with endocrine therapy (tamoxifen or an aromatase inhibitor), as an adjuvant treatment for adults with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-), node-positive early breast cancer.

With this approval, the FDA made abemaciclib the first CDK4/6 inhibitor approved for adjuvant treatment of breast cancer. The drug is indicated for patients whose cancer has a high risk of recurrence and a Ki-67 score of 20% or higher, as determined by the Ki-67 IHC MIB-1 pharmDx assay—the companion test garnered an FDA approval alongside abemaciclib.

This approval was based on results from the monarchE trial, a phase III, randomized, open-label, two-cohort multicenter trial in a cohort of adult women with HR+, HER2-, node-positive, resected EBC with clinical and pathological features consistent with a high risk of disease recurrence.

“In the trial, patients were randomized to receive two years of [abemaciclib] 150 mg twice daily plus physician’s choice of standard endocrine therapy, or standard endocrine therapy alone,” the drug’s manufacturer, Eli Lilly and Company, explained in a company press release. “Patients in both treatment arms were instructed to continue to receive adjuvant endocrine therapy for up to 5-10 years as recommended by their clinician.”

The primary study outcome was invasive disease-free survival (IDFS), the FDA explained.

“In patients with high risk of recurrence and Ki-67 Score ≥20% (n=2003), the trial demonstrated a statistically significant improvement in IDFS ([hazard ratio] 0.626; 95% CI: 0.488, 0.803; P=0.0042),” the agency wrote. “IDFS at 36 months was 86.1% (95% CI: 82.8, 88.8) for patients receiving abemaciclib plus tamoxifen or an aromatase inhibitor and 79.0% (95% CI: 75.3, 82.3) for those receiving tamoxifen or an aromatase inhibitor. Overall survival data were not mature at the time of the IDFS analysis.”

The most common side effects associated with treatment with abemaciclib included diarrhea, infections, neutropenia, fatigue, leukopenia, nausea, anemia, and headache.

The recommended dose for abemaciclib is 150 mg taken twice daily in combination with tamoxifen or an aromatase inhibitor until completion of two years of treatment, disease recurrence, or unacceptable toxicity.

John McKenna, Associate Editor, BreakingMED™

Cat ID: 22

Topic ID: 78,22,730,22,691,192,725,925