Plasma levels of TIMP-1 in chemo-naive patients with metastatic colorectal cancer treated with first-line FLOX with or without cetuximab: Results from the Nordic VII Study.

Abstract

392 Background: KRAS status is presently the best known biomarker to select patients with metastatic colorectal cancer (mCRC) for therapy with EGFR inhibition. However, in NORDIC VII a survival benefit of adding cetuximab to the Nordic FLOX regimen could not be confirmed. Plasma Tissue Inhibitor of MetalloProteinases-1 (TIMP-1) is a promising biomarker in patients with mCRC, and has multiple actions including regulation of apoptosis, angiogenesis, cell growth and differentiation. High levels of TIMP-1 associate with reduced sensitivity to irinotecan-based treatment in patients with mCRC. We investigated whether high plasma TIMP-1 also correlates with response rate, progression-free survival (PFS) and overall survival (OS) in patients with mCRC treated in NORDIC VII. Methods: In NORCIC VII 571 patients with mCRC were randomized to: (A) Nordic FLOX; (B) Nordic FLOX + cetuximab or (C) Nordic FLOX intermittently + cetuximab continuously. Baseline plasma samples for TIMP-1 analysis were available from 426 patients (79%). Plasma TIMP-1 was determined using the MAC15 antibody in-house validated kinetic Enzyme Linked Immunosorbent Assay. Results: Median plasma TIMP-1 was 296 ng/mL. The tumor was KRAS mutated in 149 patients (35%). Best response did not correlate to TIMP-1 values (OR=1.16, 0.91-1.49, p=0.22). High plasma TIMP-1 was associated with short PFS (HR=1.22, 1.07-1.39, p=0.003) and OS (HR=1.55, 1.36-1.80, p<0.0001). Multivariate analysis (TIMP-1, age, gender, KRAS, ALP, WBC, platelets, CRP, CEA, WHO PS, no. of metastatic sites) demonstrated that high plasma TIMP-1 was not an independent biomarker of PFS (HR=0.95, 0.76-1.18, p=0.65) or OS (HR=1.17, 0.91-1.50, p=0.22). Multivariate analysis retained CRP, PS and no. of metastatic sites in the final model for PFS and alkaline phosphates, PS and no. of metastatic sites for OS. Conclusions: Plasma TIMP-1 is a new prognostic biomarker in patients with mCRC treated with 1st line Nordic FLOX +/- cetuximab. Due to the design of NORDIC VII, a predictive effect of plasma TIMP-1 could only be estimated for cetuximab treatment and no significant treatment by marker intervention was observed.