Clinical impact of a dose-escalation strategy for lenvatinib in differentiated thyroid cancer.

[BACKGROUND]  Treatment options for patients with differentiated thyroid cancer (DTC) who experience disease progression on lenvatinib treatment are limited. Although dose escalation of treatment with tyrosine kinase inhibitors at disease progression has been reported across cancer types, clinical significance in patients with DTC has not been investigated.

[METHODS] We retrospectively reviewed patients with DTC who experienced disease progression on lenvatinib treatment from September 2011 to June 2022. We compared subjects who received dose-escalation treatment with standard treatment of termination at the time of initial disease progression. The escalated dose was decided by referencing to the previous effective and tolerated dose.

[RESULTS] Thirty-three patients were identified, 15 with dose escalation and 18 with lenvatinib termination. In both groups, the starting dose of lenvatinib was 24 mg/day, and the median dose at initial disease progression was 10 mg/day. In the former, the median dose escalation was 6 mg/day (range: 4-12). Objective response rate, clinical benefit rate by escalation, and median treatment duration of the dose-escalation phase were 13.3%, 73.3%, and 9.9 months (95% confidence interval [CI] 5.71-27.6), respectively. Median overall survival from initial disease progression was significantly longer in the dose-escalation group (median OS: 20.4 months [95% CI 7.0-NA] vs. 3.9 months [95% CI 1.7-7.9], log-rank p-value; 0.0004, hazard ratio; 0.22 [95% CI 0.09-0.55]). There were no grade 5 adverse events, and one patient discontinued due to a grade 3 lung abscess.

[CONCLUSION] The dose-escalation strategy appears to be a safe and effective treatment option after disease progression in patients treated with lenvatinib for DTC.