1522P - S-1 monotherapy versus nanoliposomal irinotecan plus 5-fluorouracil/leucovorin regimen for second-line therapy of recurrent or metastatic pancreatic cancer (JON 2109-P)

Background

S-1, an oral fluoropyrimidine, has been used as second-line therapy for gemcitabine-refractory patients with unresectable pancreatic cancer in East Asia. Recently, nanoliposomal irinotecan plus 5-fluorouracil/leucovorin (NAPOLI-1 regimen) demonstrated efficacy in a global phase III trial and is considered the standard treatment for the same situation. There have been no direct comparisons between the efficacy of S-1 monotherapy and the NAPOLI-1 regimen.

Methods

We retrospectively collected data from 31 participating institutions on patients who received S-1 monotherapy or the NAPOLI-1 regimen as second-line therapy following gemcitabine-based treatment between September 2019 and February 2021. For the analysis, a propensity score using the inverse probability of treatment weighting method was employed to address the differences in background factors between the two groups. Subsequently, we estimated the hazard ratio (HR) for the NAPOLI-1 regimen compared to S-1 monotherapy.

Results

Of 463 eligible patients, 446 were included in the analysis after excluding 17 patients with missing data. Among them, 244 received S-1 monotherapy, and 202 received the NAPOLI-1 regimen. The median overall survival (OS) was 5.82 months in the S-1 monotherapy group and 7.33 months in the NAPOLI-1 regimen group (log-rank p = 0.005). The weighted HR estimated was 0.812 (95% confidence interval [CI], 0.651-1.014) for OS. The median progression-free survival (PFS) was 2.30 months in the S-1 monotherapy group and 3.49 months in the NAPOLI-1 regimen group (log-rank p <0.001). The weighted HR for PFS was 0.684 (95% CI, 0.557-0.840).

Conclusions

The NAPOLI-1 regimen demonstrated superior OS and PFS compared to S-1 monotherapy as a second-line therapy for patients with recurrent or metastatic pancreatic cancer.

Clinical trial identification

UMIN000048143.

Editorial acknowledgement

Legal entity responsible for the study

Japan Oncology Network in Hepatobiliary and Pancreas.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.