The impact of starting dose with or without subsequent dose escalation of liposomal irinotecan on treatment outcomes in patients with metastatic pancreatic ductal adenocarcinoma.

ABSTRACT

Liposomal irinotecan (nal-IRI) plus 5-fluorouracil and leucovorin (5-FU/LV) improves survival in patients with pancreatic ductal adenocarcinoma (PDAC) after progression to gemcitabine-based therapy. Few studies have examined whether the starting dose and dose escalation of nal-IRI in subsequent treatment cycles may influence patient outcomes and toxicity profiles. A total of 667 patients who received nal-IRI + 5-FU/LV for PDAC treatment between August 2018 and November 2020 at nine medical centers in Taiwan were included and retrospectively analyzed. Patients were allocated to the standard starting dose (SD), reduced starting dose (RD) without escalation, and RD with escalation of nal-IRI groups for comparison of survival outcome and safety. Propensity score matching (PSM) was performed to adjust for possible confounding variables. Nal-IRI was prescribed at SD, RD without escalation, and RD with escalation in 465 (69.7%), 147 (22.0), and 55 (8.2%), respectively. RD with escalation patients had significantly longer treatment cycles (6, range 2-25) than SD (5, range 1-42, P<0.001) and RD without escalation patients (4, range 1-26, P<0.001). The median overall survival (OS) of the patients were as follows SD, 6.2 months (95% confidence interval [CI], 5.7-6.7); RD with escalation, 7.6 months (95% CI, 6.1-9.2); and RD without escalation, 3.6 months (95% CI, 2.6-4.5). After PSM to adjust for potential confounders, RD without escalation patients still had the poorest OS compared to the other two groups (P<0.001), while the OS difference between SD and RD with escalation patients was insignificant (P=0.10). SD patients had higher incidences of ≥ grade 3 neutropenia and febrile neutropenia than the other two groups. Administering nal-IRI at RD followed by dose escalation in subsequent treatment cycles is safe and does not compromise survival outcomes in selected patients with PDAC receiving nal-IRI plus 5-FU/LV.