Consecutive real-world treatment experience with a reduced starting dose of lenvatinib (14 mg) plus pembrolizumab for metastatic renal cell carcinoma.

Objective: In the CLEAR trials, the starting dose of lenvatinib in lenvatinib+pembrolizumab (L + P) was set at 20 mg for renal cell carcinoma (RCC). The incidence of adverse events is not low with L + P compared with other combination immunotherapies. There have been no reports of initiating treatment at 14 mg lenvatinib in (L + P) combination treatment for metastatic RCC (mRCC).

Methods: Patients who initiated L + P for mRCC between January 2022 and 2024 in our institution were included. Clinical data were collected retrospectively. Patients' backgrounds and adverse events were summarized, and the maximum tumor shrinkage rate and treatment progress were analyzed.

Results: Eleven patients were enrolled in this study; median age: 69 years, median body weight: 63.0 kg. Two patients were female. The International Metastatic Renal Cell Database Consortium risk score was favorable in two cases, intermediate in six cases, and poor in three cases. Adverse events led to drug interruption or discontinuation of treatment in four cases, 2 months after initiating L + P. Partial response was achieved in 10 (91%) cases; stable disease was achieved in only 1 case. Almost all patients experienced some type of adverse event (AE). Only one patient discontinued treatment due to AEs.

Conclusions: Although management of AEs was essential, early drug interruption was less frequent in our study compared with the CLEAR trial Japanese cohort. The response of a reduced starting dose of 14 mg lenvatinib for mRCC was almost the same as that in the CLEAR trial.