Continuous maintenance (Maint) capecitabine (Cape) dosing for colorectal (CRC) and pancreatic cancers (PC): A single-institution, retrospective, real-world study.

789 Background: Cape is an oral fluoropyrimidine (FP) used as maint therapy in CRC and PC. While the standard FDA dosing is 1250 mg/m 2 twice daily (BID) for 14 days followed by 7 days off in a 21-day cycle, there are variations across institutions as to the preferred schedule. To improve tolerability and convenience, our institution adopted a “continuous” dosing schedule where cape is taken BID Monday-Friday (M-F) with a treatment break on Saturday and Sunday. Here, we describe our institution’s experience with continuous maint dosing in advanced CRC and PC patients (pts) and explore real-world outcomes. Methods: Pts ≥ 18 years of age treated with continuous maint cape (+/- bevacizumab) after any line of therapy for stage 4 CRC/PC or locally advanced PC between 1/2016-12/2020 were identified in the COTA real-world database. The final study population included 35 PC and 85 CRC pts. Pt characteristics were analyzed descriptively and progression-free survival (PFS) was calculated using Kaplan Meier methods. Results: Among the 35 PC pts, the median age was 66 years (IQR: 61-73), 57.1% were females, and 65.7% were Caucasian. Among the 85 CRC pts, the median age was 54 years (IQR: 47-66), 47.1% were females, and 55.3% were Caucasian. Most PC (71.4%) and CRC (57.7%) pts were initially prescribed a total daily cape dose of 2 g (range 0.5-4 g). Dose adjustments, including dosage/schedule changes, occurred 11 times amongst PC and 36 times amongst CRC pts, and the leading cause was toxicity (72.7% in PC, 55.6% in CRC). Among PC pts, 14.3% had a dose reduction, 3% had a dose increase, and 11.4% switched to an alternative dosing schedule. Among CRC pts, these rates were 32.9%, 12.9%, and 9.4%, respectively. The leading cause of maint discontinuation was progression of disease (POD) (55.6% in PC, 59.3% in CRC). Additional outcomes are summarized in the table. Conclusions: Although maint FP is an established standard of care, it is often underutilized due to inherent inconveniences and toxicities associated with FDA cape dosing or intravenous FP therapy. The PFS reported here using a continuous cape dosing (predominantly starting at 2 g daily dosing) was in range with those previously reported in PC/CRC 1 st -line maint studies using FDA cape dosing or intravenous FP. The rates of cape discontinuation attributed to toxicity we report may be confounded by not controlling for the treatment setting. We argue fixed cape dosing (1 g BID) M-F should be considered a standard maint regimen based on efficacy, convenience, tolerability, and feasibility of dose adjustments.[Table: see text]