Quality-adjusted time without symptoms or toxicity (Q-TWiST) of lenvatinib plus everolimus versus everolimus monotherapy in patients with advanced renal cell carcinoma (RCC).

Abstract

5067 Background: In the primary analysis of Study 205 phase II trial (NCT01136733), lenvatinib+everolimus (vs everolimus) significantly prolonged progression-free survival (median PFS; 14.6 vs 5.5 months, HR = 0.40, 95% CI [0.24, 0.68]) in advanced RCC patients who received one prior anti-angiogenic therapy. Overall treatment differences were evaluated in a post hoc analysis using a quality-adjusted time without symptoms of disease or toxicity of treatment (Q-TWiST) methodology. Methods: Patients’ survival time was partitioned into three mutually exclusive health states: time spent with grade 3/4 toxicity (TOX), time prior to disease progression and without grade 3/4 toxicity (TWiST) and time post disease progression (REL). Mean time spent in each state was weighted by a health-state utility associated with that state and summed to calculate the Q-TWiST. Non-parametric bootstrapping method was used to generate 95% CI, which evaluates the between-treatment differences. At base case, utility for TWiST, TOX and REL were assigned as 1.0, 0.5 and 0.5, respectively. A sensitivity analysis was used, applying utilities across the range of 0 (similar to death) to 1.0 (perfect health). A relative gain in Q-TWiST of ≥10% and ≥15% has been established in previous literature as clinically important and clearly clinically important, respectively. Results: Patients receiving lenvatinib+everolimus (n = 51) vs everolimus (n = 50) had significantly longer mean time in TWiST (10.9 vs 6.4 months; difference 4.5 [95% CI: 1.4, 7.8]) and numerically longer in TOX (1.9 vs 0.7 months; difference 1.2 [95% CI: -0.3, 3.1]) but shorter in REL (5.8 vs 8.5 months; difference -2.8 [95% CI: -6.2, 0.6]). At base case, lenvatinib+everolimus patients had a significant mean Q-TWiST gain of 3.7 months (14.7 vs 11.0; 95% CI of difference [1.3, 6.3]), with a relative gain of 24% vs everolimus. In a sensitivity analysis using alternative utility values for TWiST (varied from 0.55 - 0.9) with utility of TOX and REL both set as 0.5, absolute mean Q-TWiST gain ranged from 1.7 to 3.3 months, with a relative gain ranging from 11.0% to 21.2% (all significant). With TWiST utility set as 1.0 and utility of TOX and REL varying from 0 to 1.0, Q-TWiST gain ranged from 1.7 to 5.8 months (mostly significant and became non-significant as the REL utility gets closer to 1.0 and TOX utility gets closer to 0). Conclusions: Within Study 205, lenvatinib+everolimus resulted in a statistically significant and clinically important gain in Q-TWiST vs everolimus alone. Clinical trial information: NCT01136733 .