Abemaciclib increased progression-free survival for advanced breast cancer

This study aimed to compare abemaciclib (Verzenio) to a placebo treatment (substance with no active effect). The study concluded that it increased progression-free survival and was relatively safe to use as a first-line treatment. 

There are several treatment options for hormone positive, HER-2 negative advanced breast cancer (dependent on hormones such as estrogen for growth). Non-steroidal aromatase inhibitors (such as letrozole) are commonly used. These act by decreasing the hormone estrogen. However, new treatments are also being developed.

Abemaciclib is a treatment that inhibits the proteins CDK4 and CDK6. They are important in regulating the cell cycle and cell growth. Blocking these proteins has shown to slow the growth of hormone positive breast cancer. 

This study aimed to compare abemaciclib to a placebo treatment. 326 patients received abemaciclib while 162 received placebo. All patients were also treated with a non-steroidal aromatase inhibitor. 

Progression-free survival (time from treatment until disease progression) was significantly increased for those taking in the abemaciclib. In patients with measurable disease, the response rate was 59% for abemaciclib treament and 44% for the placebo treatment. Side effects of abemaciclib included diarrhea (81.3%). Other side-effects like neutropenia (low white cell count) were more common in abemaciclib patients (21.1%) than placebo (1.2%). 

This study concluded that abemaciclib plus a non-steroidal aromatase inhibitor improved progression-free survival and response rate for women with hormone positive, HER-2 negative advanced breast cancer. 

These results are interim results and there will be updates on this information as time passes. 

Discuss this paper with your doctor, if applicable.