Durable response by olaparib for a Japanese patient with primary peritoneal cancer with multiple brain metastases: A case report

Brain metastases (BM) from epithelial ovarian cancer (EOC) or primary peritoneal cancer (PPC) are extremely rare, accounting for 1–2.5% of all cases. Although therapeutic options, such as surgery, irradiation and chemotherapy are proven to yield survival benefit, the overall prognosis of these patients remains unsatisfactory. Poly (adenosine diphosphate‐ribose) polymerase (PARP) inhibitor, olaparib is useful for patients with recurrent EOC or PPC. However, reports suggesting the efficacy of PARP inhibitors for patients with EOC or PPC with BM are limited. We report the case of a 58‐year‐old Japanese woman with recurrent PPC with multiple BM. After obtaining informed consent from the patient, we performed BRCA testing that detected a deleterious BRCA 1 mutation. At that time, olaparib was not yet approved in Japan, we learned about the compassionate use program of olaparib called Managed Access Program (MAP). Of note, we have established a system to enroll patients in MAP. After olaparib treatment, the patient exhibited a considerable decrease of BMs. Eighteen months since the initiation of olaparib treatment, the patient has reported no evidence of disease progression. Olaparib maintenance treatment could be effective for Japanese patients with PPC and multiple BMs.