A Novel Adverse Event Associated with Olaparib Therapy in aPatient with Metastatic Breast Cancer

Olaparib wasfirst FDA approved for use in women with advanced ovarian cancer and germline BRCA mutations. Based on theresults of subsequent research, the use of this drug has been expanded to patients with metastatic breast cancer with germline BRCA mutation. With the use of a relatively new medication and a larger patient population eligible for therapy, monitoring fornovel adverse events associated with therapy is important. This case represents a patient with metastatic breast cancer andgermline BRCA2 mutation who developed erythema nodosum after initiation of therapy with olaparib capsules. Hercharacteristic rash appeared shortly after starting olaparib and recurred after restarting olaparib an additional two times. Shewas treated with short courses of prednisone therapy with or without holding olaparib with resolution of her rash. The patientwas later restarted on olaparib capsules 200 mg twice daily, and she more recently has been maintained on olaparib tablets300 mg twice daily. On both regimens, the patient experienced only attenuated episodes of erythema nodosum that have notrequired cessation of therapy or steroid therapy