The FDA granted priority review to abemaciclib for the initial treatment of advanced breast cancer, according to the drug’s manufacturer.
The agency based the designation on positive interim results from the randomized phase 3 MONARCH 3 study.
As previously reported by HemOnc Today, the results — presented in September at the European Society for Medical Oncology Congress — showed the addition of abemaciclib (Verzenio, Eli Lilly) to an aromatase inhibitor as initial endocrine-based therapy improved outcomes among postmenopausal women with hormone receptor-positive, HER-2-negative advanced or metastatic breast cancer.
The double-blind study included 493 women who either were endocrine naive or had relapsed more than 12 months after neoadjuvant endocrine therapy.
Researchers randomly assigned 328 women to abemaciclib 150 mg twice daily plus a nonsteroidal aromatase inhibitor (anastrozole 1 mg daily or letrozole 2.5 mg daily). The other 165 women received a nonsteroidal aromatase inhibitor plus placebo.
Investigator-assessed PFS served as the primary objective. Secondary objectives included objective response rate and safety.
An interim analysis performed at 18 months showed the addition of abemaciclib — a cyclin-dependent kinase (CDK) 4/6 inhibitor — significantly extended median PFS (not reached vs. 14.7 months; HR = 0.54; 95% CI, 0.4-0.72).
Among patients with measurable disease, researchers reported a higher overall response rate in the abemaciclib group (59% vs. 44%; P = .004).
The most frequent adverse events included diarrhea (all-grade, 81.3% for abemaciclib vs. 29.8% for endocrine therapy alone; grade 3, 9.5% vs. 0%), neutropenia (all-grade, 41.3% vs. 1.9%; grade 3/grade 4, 21.1% vs. 1.2%), and fatigue (all-grade, 40.1% vs. 31.7%; grade 3/grade 4, 1.8% vs. 0%).
In September, the FDA approved abemaciclib for the treatment of women with hormone receptor-positive, HER-2-negative advanced or metastatic breast cancer who progressed following endocrine therapy.
“On the heels of our recent FDA approval of Verzenio, we are pleased with this important step forward in the agency's consideration to expand the use of Verzenio in metastatic breast cancer,” Levi A. Garraway, MD, PhD, senior vice president of global development and medical affairs at Lilly Oncology, said in a company-issued press release. “We look forward to ongoing collaboration with the FDA to advance this important treatment across the spectrum of care for patients living with advanced or metastatic breast cancer.”
Earlier this week, Lilly Oncology announced a phase 3 trial designed to evaluate abemaciclib monotherapy for KRAS-mutated advanced non-small lung cancer failed to meet its primary endpoint of improved OS.