The U.S. Food and Drug Administration (FDA) has approved a new drug Verzenio (abemaciclib) for the treatment of advanced or metastatic hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer.
This drug is approved for patients who have already been treated with hormone therapy or treatment that has altered her hormonal balance. Verzenio is to be administered along with a hormone therapy called fulvestrant after the non response to the hormone therapy alone. In patients who have had hormone therapy and chemotherapy that have had metastasis or spread of the cancer, Verzenio may be administered alone.
Richard Pazdur, M.D., 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 in the press release said, “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”. Thousands of women suffer from breast cancer worldwide and of those in USA, nearly 72 percent of patients test HR-positive and HER2-negative.
According to the information submitted to the agency for approval, this novel agent Verzenio acts by blocking cyclin-dependent kinases 4 and 6 which are actually molecules that promote the growth of cancer cells. Abemaciclib is one of the three drugs that belong to this class. The other two drugs – palbociclib and ribociclib have already been approved in February 2015 and March 2017 respectively.
For approval the manufacturers submitted the clinical trial reports where Verzenio was studied in combination with fulvestrant. In the randomized controlled clinical trial, the makers looked at 669 patients with HR-positive, HER2-negative breast cancer. Each of the cases had progressed to advanced cancer or metastasis after endocrine therapy. They had not received chemotherapy after spread of the cancer. They looked at the time taken for the tumors to grow after treatment or progression free survival. Results showed that the median progression-free survival for those patients who were given Verzenio with fulvestrant was around 16.4 months. This was significantly higher than the 9.3 months for patients who were given placebo along with fulvestrant.
Yet another study looked at use of Verzenio as a single therapy in a group of 132 patients who were diagnosed with HR-positive, HER2-negative breast cancer and had already received hormone therapy and also chemotherapy after their disease had metastasized or spread. The end point of this study was the percentage of patients in whom the cancers shrank completely or partially after treatment. This was called objective response rate. Results revealed that 19.7 percent patients who were given Verzenio showed complete or partial shrinkage in their tumors over a median period of 8.6 months.
The makers report that Verzenio shows side effects such as reduction of numbers of white blood cells, propensity to get infections, anemia, diarrhea, nausea, vomiting, abdominal pain, headache and reduced appetite. Infections due to suppressed white blood cell counts could become serious. Other major risks include liver damage, risk of blood clots or thromboembolism. Verzenio is not to be administered to pregnant women as it may damage the unborn baby.
Verzenio received a Breakthrough Therapy designation as well as received a Priority Review for approval.