New Drugs, Old Toxicities: Pneumonitis Related to Palbociclib - A Case Report.

Background: Palbociclib is a specific inhibitor of cyclin-dependent kinases 4 and 6 that is approved for the treatment of advanced or metastatic breast cancer patients. Despite a good toxicity profile in pivotal trials, where asymptomatic neutropenia was the main adverse effect, its wider use in clinical practice may show less prevalent but serious toxicities.