Abemaciclib
CDK inhibitor
Abemaciclib, sold under the brand name Verzenio among others, is a medication for the treatment of advanced or metastatic breast cancers. It was developed by Eli Lilly and it acts as a CDK inhibitor selective for CDK4 and CDK6.
It was designated as a breakthrough therapy for breast cancer by the US Food and Drug Administration (FDA) in October 2015.
In September 2017, it was approved for use in the United States by the FDA for the treatment of certain breast cancers.
Medical uses
Since September 2017, abemaciclib has been approved in the US for "adults who have hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer that has progressed after taking therapy that alters a patient's hormones".
In studies that compared fulvestrant plus abemaciclib to fulvestrant plus placebo in breast cancer patients, progression-free survival under abemaciclib therapy was 16.4 months on average, as compared to 9.3 months under the placebo arm.
Side effects
Side effects that occurred in 20% or more of patients in studies were diarrhea, nausea and vomiting, leukopenia (low white blood cell count) including neutropenia, anemia (low red blood cell count), thrombocytopenia (low platelet count), stomach pain, infections, fatigue, decreased appetite, and headache.
Interactions
As abemaciclib is mainly metabolized by the liver enzyme CYP3A4, inhibitors of this enzyme (such as ketoconazole) are expected to increase its blood plasma concentrations. Conversely, CYP3A4 inducers lower plasma concentrations of abemaciclib, as has been shown in a study with rifampicin.
Pharmacology
Mechanism of action
Like the related drugs palbociclib and ribociclib, abemaciclib inhibits the enzymes cyclin-dependent kinase 4 (CDK4) and cyclin-dependent kinase 6 (CDK6).
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