Palbociclib-induced severe hepatitis: A case study and literature review.

Palbociclib is a selective and reversible CDK4/6 inhibitor approved for patients presenting with HR+ HER2- locally advanced or metastatic breast cancer. Its adverse effect (AE) is mainly reported on the occurrence of leukopenia and fatigue. Even though palbociclib has an extensive hepatic metabolism, there are rare reports about significant liver toxicity. We present the case of a 61-year-old female with metastatic breast cancer treated with palbociclib and an aromatase inhibitor (letrozole). The patient developed a rare AE of severe acute drug-induced hepatitis but improved dramatically after stopping the palbociclib and receiving treatment with N-acetylcysteine (NAC). The treatment with NAC may be a proof of concept for the mechanism of palbociclib liver injury.