BACKGROUND: In the phase 2 double-blind Study 211, a starting dose of lenvatinib 18mg/day was compared to the approved starting dose of 24mg/day in patients with radioiodine-refractory differentiated thyroid cancer (RR-DTC). Predefined criteria for noninferiority for efficacy in the 18mg arm were not met; safety was similar in both arms. Impact of lenvatinib treatment on health-related quality-of-life (HRQoL) was a secondary endpoint of Study 211.
METHODS: Patients with RR-DTC were randomly assigned to a blinded starting dose of lenvatinib 18mg/day or 24mg/day. HRQoL was assessed at baseline, every 8 weeks until week 24, then every 16 weeks, and at the off-treatment visit, using the EQ-5D-3L and FACT-G instruments. Completion and compliance rates, mean change from baseline, and times to first and definitive deterioration were evaluated.
RESULTS: Baseline EQ-5D and FACT-G scores, and overall changes from baseline, were comparable between patients in the lenvatinib 18mg/day (n=77) and 24mg/day arms (n=75). For the 18mg versus 24mg arms, least squares mean differences were −0.42 (95% CI −4.88, 4.03) for EQ-5D-VAS and 0.47 (95% CI −3.45, 4.39) for FACT-G total. Time to first deterioration did not significantly favor either arm; EQ-5D-VAS HR [18mg/24mg] 0.93 (95% CI 0.61–1.40), EQ-5D-HUI HR [18mg/24mg] 0.68 (95% CI 0.44–1.05), FACT-G total HR [18mg/24mg] 0.73 (95% CI 0.48–1.12). Time to definitive deterioration did not significantly favor either arm, though EQ-5D-VAS showed a trend in favor of the 24mg arm (HR [18mg/24mg] 1.72; 95% CI 0.99–3.01); EQ-5D-HUI HR [18mg/24mg] was 0.96 (95% CI 0.57–1.63), FACT-G total HR [18mg/24mg] was 0.72 (95% CI 0.43–1.21).
CONCLUSIONS: In Study 211, HRQoL for patients in the lenvatinib 18mg/day arm was not statistically different from that of patients in the 24mg/day arm. These data further support the use of the approved lenvatinib starting dose of 24mg/day in patients with RR-DTC.
