Determinants of first-line treatment selection in advanced pancreatic ductal adenocarcinoma (PDAC).

Abstract

468 Background: Chemotherapy options currently available for the first-line treatment of advanced PDAC include FOLFIRINOX (FX), gemcitabine with nab-paclitaxel (GP) and single agent gemcitabine (Gem). GP was introduced most recently and funded for clinical use in British Columbia (BC) in September 2014. In this retrospective analysis, we explore the impact of GP availability on first-line treatment selection and overall survival (OS) in advanced PDAC. Methods: The BC Cancer Agency provincial pharmacy database was used to identify patients (pts) who started FX, GP or Gem between January and August 2014 (pre-GP) or January and August 2015 (post-GP). Pts were eligible for inclusion if they received at least one cycle of first-line therapy for locally advanced or metastatic PDAC. Clinical data were extracted from electronic medical records. OS was defined as time from diagnosis of advanced PDAC to death and compared by treatment era, adjusting for age, ECOG, comorbidities, disease extent and baseline CA19-9. Results: 286 pts fulfilled eligibility criteria: 88 (31%) with locally advanced and 198 (69%) with metastatic disease. 131 and 155 pts were treated in the pre- and post-GP eras respectively. Prior to GP approval, 44% and 49% of pts received Gem and FX; this decreased to 21% and 33% after GP funding, with 46% of pts receiving GP in the latter period. Nine (7%) pts received GP in the pre-GP era, either through self-pay or addition of nab-paclitaxel after approval. There were no significant differences in pt characteristics across both eras. 46% of pts who received GP post approval had ECOG ≥ 2. The proportion of pts receiving second-line therapy was lower in the post-GP era (22% vs. 38%). Median OS in the post-GP era was 8.1 vs. 10.1 months in the pre-GP era; adjusted HR 1.28 (95% CI 0.96–1.71). Pts with ECOG ≥ 2 who received GP had a median OS of 6.5 months. Conclusions: After GP was funded, it became the preferred first-line regimen for advanced PDAC. Its more frequent use instead of FX did not appear to compromise overall survival even though a substantial proportion of pts were ECOG ≥ 2 and few pts received second-line therapy.