Dosing Pattern and Early Cumulative Dose of Liposomal Irinotecan in Metastatic Pancreatic Cancer

Introduction: This multicenter, real-world cohort study aimed to evaluate the effectiveness of early cumulative dose administration and dosing pattern of liposomal irinotecan plus fluorouracil/leucovorin (nal-IRI+5-FU/LV) in patients with gemcitabine-refractory metastatic pancreatic ductal adenocarcinoma (mPDAC). Material and Methods: The electronic medical records of mPDAC patients treated with nal-IRI+5-FU/LV in nine participating centers were manually reviewed. To accommodate to the NAPOLI-1 study population, only patients with an Eastern Cooperative Oncology Group Performance Score of 0–1 were included. The survival impact of the relative 6-week cumulative dose and dosing pattern (standard vs. reduced starting dose, with and without further dose modification) were investigated. Results: Of the 473 included patients, their median overall survival (mOS) was 6.8 [95% CI, 6.2–7.7] months. The mOS of patients who received a relative 6-week cumulative dose of >80%, 60%–80%, and <60% were 7.9, 8.2, and 4.3 months, respectively (p<0.0001). Their survival impact remained significant after covariate adjustment using Cox regression. The mOS was 8.0–8.2 months in patients with a standard starting dose with and without early dose modification, and 9.3 and 6.7 months in those who had a reduced starting dose with and without escalation in the subsequent treatment, respectively. The incidence of grade 3–4 neutropenia and diarrhea was 23.3% and 2.7%, respectively. Conclusion: Our results support the use of nal-IRI+5-FU/LV in gemcitabine-refractory mPDAC and suggest that a lower starting dose followed by a re-escalation strategy could achieve clinical outcomes comparable to those with standard starting doses in real-world practice.