FDA Approves Abemaciclib for Advanced, Metastatic Breast Cancer

The FDA granted approval today to abemaciclib (Verzenio) for the treatment of adults with hormone receptor (HR)-positive, human epidemical growth factor receptor (HER2)-negative advanced or metastatic breast cancer that progressed after undergoing endocrine therapy.

Abemaciclib is designed to block cyclin-dependent kinases 4 and 6, which play a role in promoting cancer cell growth, according to a press release.

“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-along treatment to patients who were previously treated with endocrine therapy and chemotherapy,” 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, said in the release.

Investigators evaluated the safety and efficacy of abemaciclib in combination with fulvestrant in 669 patients with HR-positive, HER2-negative breast cancer that progressed after endocrine therapy and who had not received chemotherapy after the disease metastasized.

The primary endpoint was progression-free survival (PFS), with the median PFS for participants in the abemaciclib plus fulvestrant arm 16.4 months compared with 9.3 months for patients in the placebo plus fulvestrant arm.

To examine the safety and efficacy of abemaciclib as a stand-alone treatment, the investigators enrolled 132 patients with HR-positive, HER2-negative breast cancer that had progressed after endocrine therapy and chemotherapy after the cancer spread.

The primary endpoint was the objective response rate, which was the percentage of patients whose tumors partially or completely shrank after treatment. The findings showed 19.7% of patients in the abemaciclib arm experienced a complete or partial shrinkage of tumors for a median 8.6 months.

The most common adverse events (AEs) of abemaciclib were diarrhea, neutropenia and leukopenia, nausea, abdominal pain, infections, fatigue, anemia, decreased appetite, vomiting, and headache.

Serious AEs included diarrhea, neutropenia, deep venous thrombosis, and pulmonary embolism.

Breast cancer is the most common form of cancer in the United States, with approximately 72% of patients with tumors that are HR-positive and HER2-negative.