Is second-line targeted therapy beneficial in patients (pts) with differentiated thyroid cancer (DTC) after first-line sorafenib (SOR) failure?

Abstract

e17016 Background: SOR has demonstrated efficacy in phase II trials but responses are not durable. 2nd line therapy is used in clinical practice however there are no data showing clinical benefit with this approach. We sought to determine if 2nd line targeted therapy was beneficial after SOR failure. Methods: Adult pts with DTC treated with 1st line SOR for >3 months were included. We compared overall survival (OS) in pts who received only 1st line SOR (grp 1) with pts treated with 2nd line therapy after 1st line SOR failure (grp 2). OS was defined as time after SOR failure until death. SOR failure was defined as discontinuation due to progression or intolerable toxicity. Results: We identified 62 DTC pts from 2006-2012 who were treated with 1st line SOR. 10 pts in grp 1 were excluded due to missing data, secondary unrelated cancers and <3 mo on SOR. We included 52 pts: 31 in grp 1 and 21 in grp 2. Baseline characteristics were similar between groups (Table). FTC was more frequent in grp 2. 2nd therapy included sunitinib, pazopanib, vemurafenib, and other investigational drugs. Median time on treatment with 2nd line therapy was 14.5 mo. Median OS in grp 1 and grp 2 was 6 and 50 mo, respectively (p=0.002). After excluding pts for death <3 mo after SOR end, median OS was 20 and 50 mo; there was a trend toward significance (p=0.07). Response and updated analysis will be reported at the meeting. Conclusions: Our study shows that pts receiving 2nd line therapy after SOR failure had a long OS despite more pts with FTC in this group. Acknowledging the limitations of a retrospective study, we conclude that in DTC pts, salvage targeted therapy after SOR failure appears to be beneficial and a promising strategy. [Table: see text]