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The U.S. Food and Drug Administration has granted Breakthrough Therapy status to abemaciclib for the treatment of patients with refractory hormone-receptor-positive advanced or metastatic breast cancer. Abemaciclib, marketed by Lilly Oncology, is a cyclin-dependent kinase 4 and 6 inhibitor.

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The designation, enacted as part of the FDA's 2012 Safety and Innovation Act, was created to expedite the development and review time of a potential new drug for serious or life-threatening disease where early clinical evidence suggests the drug may demonstrate substantial improvement compared with existing therapies.


This designation for abemaciclib is based on data from the breast cancer cohort expansion of the Phase I JPBA trial, which studied the efficacy and safety of the drug in women with advanced or metastatic breast cancer. The patients in this trial cohort had received a median of seven prior systemic therapies. The data were presented at the San Antonio Breast Cancer Symposium in 2014.


Abemaciclib is also being evaluated in the ongoing Phase II MONARCH 1 trial for women with hormone-receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer. And the drug is also being assessed in two Phase III clinical trials:


* MONARCH 2 to evaluate the combination of abemaciclib and fulvestrant in postmenopausal patients with patients with hormone-receptor-positive, HER2-negative advanced or metastatic breast cancer; and


* MONARCH 3 to evaluate the combination of abemaciclib and a nonsteroidal aromatase inhibitor in patients with hormone-receptor-positive, HER2-negative locoregionally recurrent or metastatic breast cancer.