FDA approves abemaciclib for certain HR+ metastatic breast cancers
CDK 4/6 inhibitor gets speedy approval for people for whom other treatments have stopped working
The Food and Drug Administration has approved abemaciclib (Verzenio), both on its own and in combination with fulvestrant (Faslodex), to treat hormone receptor-positive metastatic breast cancers after other treatments have stopped working.
Abemaciclib works by blocking two proteins — cyclin-dependent kinases 4 and 6 — that cause some breast cancers to grow. Medicines like abemaciclib that work against these proteins are called CDK 4/6 inhibitors. Two other CDK 4/6 inhibitors have been approved for breast cancer treatment since 2015: ribociclib (Kisqali) and palbociclib (Ibrance).
The approval comes just 2 months after maker Eli Lilly and Company announced its application had been given Priority Review status from the FDA. Priority Review is a program where the FDA says it will respond to an application more quickly than it typically would. It is awarded to medicines that may significantly improve effectiveness of or safety for treatment of a serious condition.
The FDA approved two uses for abemaciclib in people who have hormone receptor-positive, HER2-negative metastatic breast cancer. It can be
- given alone after a breast cancer has already been treated with hormonal therapy and chemotherapy
- given with fulvestrant after a breast cancer has been treated with hormonal therapy
Results that drove these approvals came from the MONARCH 1 and MONARCH 2 trials, respectively.
The phase II MONARCH 1 trial tested abemaciclib given alone in 132 people with hormone receptor-positive, HER2-negative metastatic breast cancer that had grown after treatment with hormonal therapy and chemotherapy. Participants took abemaciclib by mouth, twice a day until cancer grew again or they had side effects that were too toxic. The study found 19.7 percent of people had their cancer respond the treatment.
MONARCH 2 was a phase III trial that tested abemaciclib given twice daily with the hormonal therapy fulvestrant. It was also for people with hormone receptor-positive, HER2-negative metastatic breast cancer but with cancers that had progressed after another hormonal therapy. MONARCH 2 was a randomized double-blind study with 446 people getting fulvestrant and abemaciclib and 223 people getting fulvestrant and a placebo. People getting both treatments went longer without breast cancer growing, a median of 16.4 months compared to 9.3 months for the placebo group. The dose had to be adjusted during the trial due to a high number of people getting diarrhea, but the side effect was better managed at the lower dose.
People eligible to take abemaciclib together with fulvestrant had breast cancer progress during hormonal therapy for early-stage breast cancer, within a year of stopping hormonal therapy or during first-line hormonal therapy for metastatic breast cancer. They should not have gotten chemotherapy or a second hormonal therapy for metastatic breast cancer.
What This Means for You
Abemaciclib is the third CDK 4/6 inhibitor to get FDA approval in just 3 years, joining ribociclib and palbociclib. Managing metastatic breast cancer requires a series of treatments, and when one fails to keep the disease from growing, you may be given a different treatment. Finding new and more effective treatments can mean more time between having to get used to new treatments and side effects. Medicines like abemaciclib, which is taken by mouth, can also help delay chemotherapy infusions which interrupt your daily life and may come with more burdensome side effects.
You may be eligible for abemaciclib as a future treatment. Your doctor can help you understand your treatment options and whether you would benefit from abemaciclib if your disease progresses. If your doctor recommends abemaciclib for your treatment, Eli Lilly has some patient resources available at Verzenio.com including a support line and financial assistance.