Angelica Petrillo,1 Giuseppe Tirino,1 Federica Zito Marino,2 Luca Pompella,1 Rosalaura Sabetta,2 Iacopo Panarese,2 Annalisa Pappalardo,1 Marianna Caterino,1 Anna Ventriglia,1 Maria Maddalena Laterza,1 Floriana Morgillo,1 Michele Orditura,1 Fortunato Ciardiello,1 Renato Franco,2 Ferdinando De Vita1 1Division of Medical Oncology, Department of Precision Medicine, School of Medicine, University of Study of Campania “Luigi Vanvitelli”, Naples 80131, Italy; 2Pathology Unit, University of Study of Campania “Luigi Vanvitelli”, Naples 80138, ItalyCorrespondence: Angelica Petrillo Tel +39-0815666729Email angelic.petrillo@gmail.comFerdinando De Vita Tel +39-0815666713Email ferdinando.devita@unicampania.itPurpose: ATTRACTION-2 trial assessed the role of Nivolumab as a new standard treatment for Asian patients with pretreated metastatic gastric cancer (mGC). The aim of this analysis was to evaluate the safety and efficacy of Nivolumab in a real-life Western population, considering the lack of evidence to date.Patients and Methods: Patients progressed after ≥ 2 chemotherapy regimens and able to receive Nivolumab (3 mg/kg q14) were eligible for the analysis.Results: 16 patients received Nivolumab as third (81.3%) or fourth line (18.7%) from September 2017 to July 2019. The safety was in line with the literature and only one patient discontinued treatment due to persistent hematological toxicity. Overall response rate and disease control rate were 18.7% and 31.2%, respectively. Median duration of response was 5 months. With a median follow-up of 21 months, median OS was 6 months (7, 21 and 22 months in the responders) and median PFS 3 months. PD-L1 and microsatellite status were retrospectively collected in 12 patients. All the major responders were MSI, although no statistically significant difference in OS or PFS was observed according to molecular analysis.Conclusion: Nivolumab is feasible and effective in Western patients with mGC. Further investigation is urgently needed also in non-Asians.Keywords: immune-checkpoint inhibitors, nivolumab, immunotherapy, third line, PD-L1, MSI