Tezcan, H.

480 Background: COs associated with varying Tx patterns in mCRC pts are poorly understood because patterns diverge from the randomized trials (RCT). The RCTs of BV (Avastin) plus chemotherapy (CT) in mCRC pts continued BV until progressive disease (PD), even if CT was stopped/changed. Some RCTs of BV+CT in mCRC show ∼50% of pts stopping Tx early for reasons other than PD with possible lessening of benefit. It is unclear if this is due to use of a particular CT regimen or other practice pattern. While the beneficial effect of post-PD BV Tx has been shown in ARIES (HR 0.52 BBP vs No BBP) [A Cohn, ASCO 2010], the effect of stopping BV or CT before PD is unclear. ARIES, a community based observational study with a large cohort of 1st line BV-treated mCRC pts, will assess the COs associated with different 1st line Tx patterns (BV and CT) based on real world practice. Methods: ARIES enrolled mCRC pts receiving first- or second-line CT+BV. No Tx regimens or assessments are protocol specified. Data are collected prospectively at baseline (BL) and quarterly. Analyses included first-line pts with PD. Tx patterns of pts initially treated with FOLFOX/BV or FOLFIRI/BV are described and preliminary COs (PFS and OS) are estimated from K-M curves. Tx duration is calculated from enrollment date. Results: As of 2/5/10, 1,548 first-line mCRC pts enrolled (median follow up = 21 m); 1,133 pts had PD. Of 1,133 pts with PD, most had FOLFOX/BV (63%) or FOLFIRI/BV (16%) as first CT. BL characteristics were similar, but the FOLFOX/BV group had more stage 4 pts (74%). Main reasons for stopping BV include AE, max benefit achieved and CT holiday. Tx patterns and COs are in the table. Conclusions: ARIES first-line mCRC pts treated with FOLFOX/BV or FOLFIRI/BV had similar Tx patterns and COs despite the common opinion that they may differ in tolerability and possibly effectiveness. Additional analyses will assess the impact of stopping BV and/or CT before PD. [Table: see text] [Table: see text]