4098 Background: A recent randomized phase III trial with a 2x2 factorial design compared 4 chemotherapy regimens as first-line treatment for MCRC: oral capecitabine + i.v. oxaliplatin q3w (XELOX); 5-FU/LV + i.v. oxaliplatin (FOLFOX4); XELOX+A; and FOLFOX4+A. The XELOX regimens were found to be non-inferior to FOLFOX4 in terms of progression-free survival (the primary endpoint), and the A regimens were superior to the placebo arms. The attractiveness of these regimens to providers, patients, and payers will also depend on the medical resources involved. The purpose of this analysis was to compare the expected resource use across the 4 groups. Methods: A resource use model was constructed based on trial data and projections from trial protocols. Both medical resources and patient time were considered. The medical resources included visits for chemotherapy administration, central venous access (CVA), treatment of adverse events (AEs), and hospital use for common treatment-related AEs. Patient time for chemotherapy administration, ambulatory visits, and hospital stays was estimated. Results: FOLFOX and FOLFOX4+A required more administration visits due to the q2w cycle (22–27 visits in total for the FOLFOX arms vs. 7–9 visits for the XELOX arms). With FOLFOX regimens, patients spend 60–200 additional hours receiving i.v. drug administration, and 22–27 additional hours traveling and waiting to receive chemotherapy. The rate of hospital admissions for common AEs did not differ among the arms, but mean hospital days for common AEs were slightly higher in the XELOX arms. Ambulatory encounters to treat AEs added only about 1 hour of encounter time per patient on average in all 4 arms. The 2 FOLFOX4 arms had twice as many placements for CVA. Conclusion: In the first-line setting, the 2 FOLFOX4 chemotherapy regimens involve substantially more i.v. drug administration visits and time - the equivalent of more than two 40-hour workweeks. The 4 regimens were similar in terms of the amount of resource use needed to treat AEs. No significant financial relationships to disclose.