Analysis of Biomarkers and Association With Clinical Outcomes in Patients With Differentiated Thyroid Cancer: Subanalysis of the Sorafenib Phase III DECISION Trial.

ABSTRACT

PURPOSE: The phase III DECISION trial (NCT00984282; EudraCT2009-012007-25) established sorafenib efficacy in locally recurrent or metastatic, progressive, differentiated thyroid cancer (DTC) refractory to radioactive iodine. We conducted a retrospective, exploratory biomarker analysis of patients from DECISION. EXPERIMENTAL DESIGN: Candidate biomarkers [15 baseline plasma proteins, baseline and during-treatment serum thyroglobulin, and relevant tumor mutations (BRAF, NRAS, HRAS, and KRAS)] were analyzed for correlation with clinical outcomes. RESULTS: Plasma biomarker and thyroglobulin data were available for 395 of 417 (94.7%) and 403 of 417 (96.6%) patients, respectively. Elevated baseline VEGFA was independently associated with poor prognosis for progression-free survival [PFS; HR = 1.82; 95% confidence interval (CI), 1.38-2.44; P = 0.0007], overall survival (HR = 2.13; 95% CI, 1.37-3.36; P = 0.013), and disease-control rate (DCR; OR = 0.30; P = 0.009). Elevated baseline thyroglobulin was independently associated with poor PFS (HR = 2.03; 95% CI, 1.52-2.71; P < 0.0001) and DCR (OR = 0.32; P = 0.01). Combined VEGFA/thyroglobulin signatures correlated with poor PFS (HR = 2.12; 95% CI, 1.57-2.87; P < 0.00001). Thyroglobulin decrease ≥30% from baseline was achieved by 76% and 14% of patients receiving sorafenib and placebo, respectively (P < 0.001). Patients with ≥30% thyroglobulin reduction had longer PFS than those without ≥30% reduction [HR (95% CI) sorafenib = 0.61 (0.40-0.94), P = 0.022; placebo = 0.49 (0.29-0.85), P = 0.009]. BRAF mutations were associated with better PFS; RAS mutations were associated with worse PFS, although neither was independently prognostic in multivariate models. No examined biomarker predicted sorafenib benefit. CONCLUSIONS: We identified biomarkers associated with poor prognosis in DTC, including elevated baseline VEGFA and thyroglobulin and the presence of RAS mutations. Serum thyroglobulin may be a biomarker of tumor response and progression.