The regimen of nanoliposomal irinotecan plus 5-fluorouracil and leucovorin (Nal-IRI/FL) was approved in Japan as second-line chemotherapy after gemcitabine-based treatment for pancreatic ductal adenocarcinoma (PDAC) in 2020. We examined the difference in outcome between patients treated with second-line folinic acid, fluorouracil, irinotecan hydrochloride and oxaliplatin (FOLFIRINOX) and those treated with nal-IRI/FL after first-line gemcitabine and nab-paclitaxel (GnP).