Background:
In SELECT, lenvatinib significantly improved progression-free survival (PFS) of patients with RR-DTC versus placebo (18.3 vs 3.6 months; hazard ratio [HR]: 0.21 [99% CI: 0.14, 0.31]; P<0.001). Here we examine the treatment of RR-DTC with lenvatinib in relation to tumor size (sum of all targeted lesions) and ECOG PS.
Methods:
In this post hoc analysis of SELECT with patients randomized to receive lenvatinib, Kaplan-Meier estimates of time to ECOG PS ≥2 were calculated for subgroups of patients according to baseline ECOG PS or tumor size. Objective response rate (ORR) and Kaplan-Meier estimates of overall survival (OS) and PFS according to ECOG PS (0 or 1) at baseline were calculated. Percentage change from baseline to postbaseline nadir in the sum of diameters of target lesions and percentage change over time according to ECOG PS at baseline (0 or 1) were assessed.
Results:
Patients with ECOG PS 0 or 1 at baseline had similar demographic and disease characteristics. ORR was 78.5% and 51.0% for patients with ECOG PS 0 and 1 at baseline, respectively (odds ratio [95% CI]: 3.508 [2.018, 6.097]). Mean maximum percent decrease in tumor size was greater in patients with baseline ECOG PS 0 (-46.13%) versus patients with ECOG PS 1 (-37.16%). For patients with ECOG PS 1 at baseline, time to ECOG PS ≥2 was numerically shorter with tumor size >60 mm versus tumor size ≤60 mm (HR [95% CI]: 1.450 [0.708, 2.967]). Additional results are summarized in the table.
Conclusions:
Among patients with RR-DTC, PFS, OS, ORR, and time to ECOG ≥2 were generally better for patients with lower ECOG PS or smaller tumor size at baseline. These results may indicate that it is beneficial to start lenvatinib in patients with RR-DTC early, before ECOG PS worsens and tumor size increases.
Clinical trial information: NCT01321554