The FDA has approved abemaciclib (Verzenio, Eli Lilly and Company) to treat adults who have hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer that has progressed after endocrine therapy.
Abemaciclib is approved to be given in combination with the endocrine therapy fulvestrant (Faslodex, AstraZeneca) after the cancer has grown on endocrine therapy. It is also approved to be given on its own, if patients were previously treated with endocrine therapy and chemotherapy after the cancer had metastasized.
"Verzenio provides a new targeted treatment option for certain patients with breast cancer who are not responding to treatment, and unlike other drugs in the class, it can be given as a stand-alone treatment to patients who were previously treated with endocrine therapy and chemotherapy," said Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research.
Abemaciclib works by blocking cyclin-dependent kinases 4 and 6, which are involved in promoting the growth of cancer cells. Two other drugs in this class are approved for certain patients with breast cancer: palbociclib (Ibrance, Pfizer), approved in February 2015, and ribociclib (Kisqali, Novartis), approved in March 2017.
Breast cancer is the most common form of cancer in the United States. The National Cancer Institute at the National Institutes of Health estimates approximately 252,710 women will be diagnosed with breast cancer this year, and 40,610 will die of the disease. Approximately 72% of patients with breast cancer have tumors that are HR-positive and HER2-negative.
The safety and efficacy of abemaciclib in combination with fulvestrant were studied in a randomized trial of 669 patients with HR-positive, HER2-negative breast cancer that had progressed after treatment with endocrine therapy and who had not received chemotherapy once the cancer had metastasized. The median progression-free survival for patients taking abemaciclib with fulvestrant was 16.4 months, compared with 9.3 months for patients taking a placebo with fulvestrant.
The safety and efficacy of abemaciclib as a stand-alone treatment were studied in a single-arm trial of 132 patients with HR-positive, HER2-negative breast cancer that had progressed after treatment with endocrine therapy and chemotherapy after the cancer metastasized. The study measured the objective response rate; 19.7% of patients taking abemaciclib experienced complete or partial shrinkage of their tumors for a median 8.6 months.
Common side effects of abemaciclib include diarrhea, neutropenia, leukopenia, nausea, abdominal pain, infections, fatigue, anemia, decreased appetite, vomiting, and headache. Serious side effects include diarrhea, neutropenia, elevated liver blood tests, deep venous thrombosis, and pulmonary embolism. Women who are pregnant should not take abemaciclib because it may cause harm to a developing fetus.
The FDA granted this application priority review and breakthrough therapy designations.
Source: FDA; September 28, 2017