Lenvatinib Monotherapy Versus Lenvatinib in Combination with PD-1 Blockades as Re-Challenging Treatment for Patients with Metastatic Osteosarcoma: A Real-World Study.

Purpose: To explore the efficacy and safety of lenvatinib, either as a monotherapy or in combination with programmed death-1 (PD-1) blockades, as re-challenging treatment in patients with metastatic osteosarcoma following treatment failure with previous tyrosine kinase inhibitors (TKIs).

Patients And Methods: We retrospectively reviewed the data of 26 patients with metastatic osteosarcoma who received rechallenge treatment with lenvatinib monotherapy or lenvatinib plus PD-1 blockades after failure of the initial TKI treatment from January 2020 to June 2024 in our center. The primary endpoint was progression-free survival (PFS). Secondary endpoints included objective response rate (ORR), clinical benefit rate (CBR), and safety.

Results: Of the 26 patients, ORR and CBR were 11.5% and 61.5%, respectively. The median duration of follow-up was 15 months (range, 4.3-25.6) with a median PFS of 7.2 months (95% CI: 1.9-12.5). A total of 14 patients received lenvatinib as a monotherapy, and 12 received a combination therapy of lenvatinib and PD-1 blockade. No significant differences were observed in ORR (0 vs 25%) and CBR (57.1 vs 66.7%) between the two groups. Additionally, the combination cohort exhibited a significantly longer PFS compared to the monotherapy cohort (8.6 [95% CI: 5.0-12.1] vs 4.0 months [95% CI: 1.0-7.0], = 0.022). 96.2% of patients experienced grade 1 or more adverse events (AEs). Grade 3 adverse events occurred in 6 (23.1%) patients. The safety profiles of the lenvatinib and PD-1 blockade combination group were found to be comparable to those of the lenvatinib monotherapy group.

Conclusion: Our data indicated that patients with metastatic osteosarcoma could potentially benefit from lenvatinib rechallenge after progress with initial TKI treatment. The combination of lenvatinib and PD-1 blockade therapy demonstrated promising survival outcomes in patients with metastatic osteosarcoma, accompanied by a manageable toxicity profile.