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

ABSTRACT

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. CASE PRESENTATION Here, we describe a case of pneumonitis due to palbocicblib. A 57-year-old female with breast cancer with bone metastasis presented dyspnea at rest 3 months after beginning treatment with palbociclib and letrozole. Palbociclib-induced pneumonitis was considered the most probable cause after ruling out all alternatives, and the patient was successfully treated with steroids and showed complete remission. CONCLUSIONS: In summary, we present a well-documented case report of pneumonitis related to palbociclib. However, the mechanism of toxicity is still unknown, and there are as yet no reliable biomarkers to predict toxicity with cyclin-dependent kinase 4/6 inhibitors. In this case report, we alert physicians about new drugs that can provoke old toxicities.