Efficacy and safety of first-line cetuximab + FOLFIRI in older and younger patients (pts) with RAS wild-type (wt) metastatic colorectal cancer (mCRC) in the CRYSTAL study.

Abstract

647 Background: Pts with mCRC are often older, thus prompting interest in subgroup analyses based on age. Adding cetuximab to FOLFIRI in the first-line CRYSTAL trial improved progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) in pts with RAS wt mCRC. This subgroup analysis evaluated the efficacy and safety of FOLFIRI ± cetuximab within age-defined subgroups from the RASwt population of CRYSTAL. Methods: PFS, OS, ORR, and safety were evaluated in RAS wt pt subgroups in CRYSTAL, defined by age and treatment arm. Older pts were categorized as aged ≥65 y; younger pts were aged <65 y. Among pts ≥65 y, only 26 and 10 pts in the cetuximab + FOLFIRI arm and only 10 and 10 pts in the FOLFIRI arm were aged 70-75 y and ≥75 y, respectively; therefore, an analysis of an older-age cutoff was not performed. Results: Among 367 pts with RASwt tumors, 115 were older and 252 were younger. Baseline characteristics were similar between treatment arms in the younger subgroup; however, in the older subgroup, baseline ECOG status (ECOG=0; 45.9% vs 61.1%) and quality of life (>median; 36.1% vs 51.9%) favored the FOLFIRI arm. This study was not designed to assess differences within and between age subgroups; therefore, interpretation is limited by baseline imbalances and the small number of older pts. Efficacy and safety data are summarized below. Conclusions: In RAS wt CRYSTAL pts, adding cetuximab to FOLFIRI improved ORR, PFS and, to a lesser extent, OS in both older and younger pts. Clinical trial information: NCT00154102. [Table: see text]