Background: Lenvatinib is recommended for the treatment of advanced and recurrent thymic carcinomas. However, there is a paucity of data on lenvatinib's use in real-world clinical practice. The aim of this study was to evaluate the efficacy and safety of lenvatinib in patients with thymic carcinoma.

Methods: This multicenter retrospective cohort study assessed the efficacy and tolerability of lenvatinib in the treatment of patients with advanced or recurrent thymic carcinoma between March 2021 and March 2024.

Results: Twenty-seven patients from six institutions in Japan were enrolled in this study. The median progression-free survival (PFS), objective response rate (ORR), and disease control rate (DCR) were 9.0 months (95% confidence interval [CI] 4.8-14.5), 33% (95% CI 16.5%-54%), and 85% (95% CI 66.3%-95.8%), respectively. Although the number of patients was small, the median PFS of the first-, second-, and third- or later-line treatment groups was 21.3 months (n = 5), 9.0 months (n = 13), and 5.8 months (n = 9) (p = 0.171), respectively. Dose reduction was required in all patients, with 17 (63%) presenting grade ≥ 3 adverse events, including hypertension in seven patients and proteinuria in six. No grade ≥ 4 adverse events were observed.

Conclusions: The real-world efficacy and safety of lenvatinib are consistent with those reported in previous clinical trials of second-line lenvatinib. Furthermore, despite the relatively small sample size, our findings suggest that lenvatinib may be effective for the treatment of thymic carcinoma.