Nivolumab versus irinotecan as third- or later-line treatment for advanced gastric cancer: a multi-center retrospective study

Background The present study aimed to compare the efficacy and safety of nivolumab (NIVO) and irinotecan (IRI) and to identify clinical factors that facilitate treatment selection. Methods Patients with advanced gastric cancer (AGC) who underwent NIVO or IRI treatment between November 2016 and June 2018 at three institutions were retrospectively reviewed. The inclusion criteria were histologically confirmed gastric/gastroesophageal adenocarcinoma pretreated with fluoropyrimidines and taxanes, no previous NIVO or IRI treatment, and adequate organ function. Main outcome measures were objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and adverse events. Interaction between treatment groups and clinical factors regarding OS were tested using a multivariate Cox proportional hazards model adjusted for relevant variables. Results Both NIVO ( n = 71) and IRI ( n = 61) groups had similar baseline characteristics, except for sex distribution. NIVO and IRI groups had ORR of 20% and 6%, median PFS of 1.6 and 1.8 months, and median OS of 6.4 and 6.4 months, respectively. Interaction analysis did not reveal any significant interaction between NIVO and IRI related to OS for various factors. NIVO group tended to have fewer ≥ grade 3 adverse events than IRI group, especially neutropenia (3% vs. 28%) and febrile neutropenia (1% vs. 8%). In the NIVO group, one patient developed pneumonitis, and four patients developed skin reactions. Conclusions Although no remarkable differences in efficacy were found between IRI and NIVO for AGC, NIVO had a better safety profile compared to IRI. We found no clinical markers that can assist treatment decisions.