Palbociclib-Induced Pneumonitis: A Case Report and Review of the Literature.

The treatment of metastatic breast cancer has undergone significant changes in recent years. New classes of medications have been approved by the Food and Drug Administration (FDA) for use in clinical practice to extend progression-free survival and overall survival along with increasing response rate. Here, we present a case report of pneumonitis as a rare side effect of palbociclib in the treatment of metastatic hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (ERBB2-) breast cancer in addition to endocrine therapy. We also review the literature for other reports of pneumonitis during treatment with palbociclib. Through this case report and review of the literature, we aim to shed light on this rare side effect of palbociclib along with its successful management.