Background: Based on the ABC 02 trial, standard therapy for ABTC is CG for up to 8 cycles. However, a recent abstract (Doherty et al, ASCO 2016) confirmed that a cohort of pts does benefit from continued therapy. The weekly administration of G and C can add significant toxicities that may prohibit prolonged treatment (trmt). Previous studies have shown that a biweekly schedule (Ko AH et al JCO 2012) of fixed dose rate (FDR) G helps optimize the prescribed regimen with an improved toxicity profile and added convenience to pts while maintaining efficacy. Methods: Pts with ABTC treated with FDR G (1000mg/m² at 10mg/m²/min) with C 20mg/m²(GC) on days 1 and 15 of every 28-day cycle were included for analysis. Pts received trmt until time of progression. Data was collected including demographics, clinico-pathologic features, toxicities and survival. Kaplan-Meier curves were used to calculate the median overall survival (OS) and progression free survival (PFS). Results: The study included 109 evaluable pts with ABTC who received CG. Pts had disease that was locally advanced (16.5%) or metastatic (83.5%). Median age was 60 years (28-86). Sites of tumor included gallbladder (21.1%), ampullary (3.6%) and bile duct (75.2%). Median number of cycles was 6 (1-27). Median PFS was 8.34 (6.74, 9.23) months and median OS was 10.32 (9.10, 11.43) months. Most common grade 3 or 4 adverse events included neutropenia (11%), fatigue (10%), thrombocytopenia (TCP) (6.4%), anemia (2.8%), and abnormal liver function tests (2.8%). Fifty-two percent of pts received second line therapy. Conclusions: Biweekly CG in ABTC is associated with a more favorable toxicity profile while maintaining efficacy similar to that observed in prior clinical trials. Minimal toxicities were observed despite a prolonged course for many. Further prospective exploration should consider evaluating the role of biweekly gemcitabine and cisplatin regimen in ABTC especially as a potentially more favorable platform to combine with novel agents.

*Acknowledging limitations of cross-study comparison.