Lilly's breast cancer study of abemaciclib demonstrated superior progression-free survival at interim analysis

The Phase III study compared abemaciclib in combination with an aromatase inhibitor versus an aromatase inhibitor alone in patients with HR+, HER2- advanced breast cancer.

"Today marks another important milestone in our clinical development program for abemaciclib, a drug we believe has the potential to be best in class," said Levi Garraway, senior vice president, global development and medical affairs, Lilly Oncology. "We are very excited about the results seen in patients with breast cancer, from single-agent activity to clinically meaningful benefit when used in combination with fulvestrant or aromatase inhibitors. Along with additional abemaciclib clinical trials in other tumor types, these data underscore Lilly's commitment to delivering life-changing medicines to treat and cure people living with cancer around the world."

The global Phase III, double-blind, placebo-controlled study was designed to evaluate the efficacy and safety of abemaciclib in combination with an aromatase inhibitor as initial endocrine-based therapy for postmenopausal women with advanced (locoregionally recurrent or metastatic) breast cancer who have had no prior systemic treatment for advanced disease. A total of 493 patients were randomized to receive 150 mg of abemaciclib or placebo orally twice a day without interruption, given in combination with either 1 mg of anastrozole or 2.5 mg of letrozole once daily until disease progression or unacceptable toxicity. The primary endpoint of the study was PFS, with key secondary endpoints of ORR, overall survival and safety. The adverse events were generally consistent with previous studies of abemaciclib, with the most common adverse events being diarrhea, neutropenia, fatigue, and nausea.

Following this MONARCH 3 interim analysis, Lilly intends to begin global submissions of these results in the third quarter of 2017. In addition, Lilly intends to initiate MONARCH 1 and MONARCH 2 submissions beginning in the second quarter of 2017.

Other MONARCH trials currently underway include: monarcHER, which is evaluating abemaciclib plus trastuzumab (with or without fulvestrant) in women with HR+, HER2+ locally advanced or metastatic breast cancer, and MONARCH plus, a Phase 3 study of abemaciclib in combination with endocrine therapies to support registration in China. In addition, Lilly has an ongoing Phase 3 trial evaluating abemaciclib in lung cancer. Lilly is also evaluating abemaciclib in patients with brain metastases, as well as in patients with pancreatic cancer.