Efficacy and safety of third- and fourth-line targeted therapy in Japanese patients with metastatic renal cell carcinoma: A retrospective analysis.

Introduction: There is limited data on the efficacy of sequential targeted therapy for metastatic renal cell carcinoma (mRCC) beyond the second line, especially for Asian patients. We evaluated the efficacy and side effects of targeted therapy beyond the second line.

Materials and Methods: We retrospectively reviewed 69 patients who were administered targeted therapy for mRCC at our institution between 2008 and 2016. Sunitinib, pazopanib, sorafenib, axitinib, everolimus, and temsirolimus were available in Japan in 2016, and treatment had been conducted with those six agents. Twenty-four patients underwent therapy beyond the second line. The progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. In addition, a survey on patients' attitudes toward cancer treatment was conducted. Twenty-five of the 69 patients responded to the question with their opinions on the continuation of treatment after standard therapy failure.

Results: The median PFS was 7.6 and 2.5 months for third- and fourth-line therapy. The median OS calculated from the initiation of third-line therapy was 14.2 months. The rates of serious toxicities with third- and fourth-line regimens were not markedly increased compared with first- and second-line therapies. Forty percent of patients hoped to continue treatment after exhausting standard care.

Conclusions: Our retrospective study indicates the efficacy and safety of third- and fourth-line targeted therapies. In addition to the efficacy, a patient can also influence treatment continuation.