Cyclin-Dependent Kinase 4/6 Inhibitor (Palbociclib) Induced Aplastic Anemia in a Patient with Metastatic Breast Cancer

Abstract

Breast cancer is the most common cancer diagnosed in women worldwide. Over the years, breast cancer treatment has undergone revolutionary changes especially for women with hormone receptor positive metastatic disease. As a result, women are living longer with their disease, particularly in developed countries. The use of cyclin-dependent kinase (CDK) 4/6 inhibitors with antiestrogen therapy is a relatively new therapeutic option which has been shown to improve progression-free survival. Hematologic adverse events, most frequently neutropenia, are well-known side effects of CDK 4/6 inhibitors. However, to our knowledge, aplastic anemia has never been reported. We report a case of aplastic anemia in a patient with metastatic breast cancer treated with palbociclib after multiple prior lines of therapy.

Clinico-Immunological Effects of a Single-Agent CDK4/6 Inhibitor in Advanced HR+/HER2− Breast Cancer Based on a Window of Opportunity Study

“…In the MONALEESA 2 trial, grade 3 and 4 lymphopenia rates were 7% and 0.9%, respectively [ 12 ]. However, the overall impact of CDK4/6 i-based therapy on peripheral blood counts in PALOMA, MONARCH, and MONALEESA trials has not been accurately discussed, and only a single case study describes a patient who developed neutropenia, thrombocytopenia, and anaemia following a palbociclib regimen [ 36 ]. It is worth mentioning that lymphopenia is a robust predictor of chemotherapy-induced toxicity and is also a predictive factor of treatment efficacy in lung, breast, and colon cancer [ 37 , 38 , 39 ].…”