[Clinical Evaluation of the Efficacy and Adverse Effects of Nivolumab Treatment for Patients with Advanced Gastric Cancer].

BACKGROUND: Nivolumab, a fully human IgG4 monoclonal antibody inhibitor of programmed death-1(PD-1), was approved for use in the treatment of patients with advanced gastric or gastroesophageal junction cancer who had been previously treated with B2 chemotherapy regimens in Japan. METHODS: We investigated the efficacy of nivolumab therapy in 15 consecutive patients with advanced gastric cancer between October 2017 and December 2018 in our facility. RESULTS: In our study, the 6-month overall survival rate was 67.7%, and the median survival time(MST)was 6.3 months. Immune-related adverse events(irAEs)occurred in the following patients: 2 patients, interstitial pneumonia(13%); 1 patient, myocarditis (6.7%); 1 patient, hypothyroidism(6.7%); and 1 patient, liver dysfunction(6.7%). Of the patients with an absolute lym- phocyte count(ALC)of C2,000/mL at baseline, 33%(4/12)experienced irAEs, while of those with an ALC of >2,000/mL, 67% had irAEs. The 6-month overall survival rate was better in patients with an ALC >1,600/mL(100%, 4/4)than in those with an ALC of C1,600/mL(35%, 4/11). The 6-month overall survival rate of the patients with a neutrophil-to-lymphocyte ratio(NLR)of <4 was 63%, which was better than the 33% rate in those with an NLR of B4. CONCLUSIONS: Nivolumab therapy was a safe and feasible treatment option. The cutoff values of ALC of 2,000/mL for irAEs and of ALC of 1,600/mL and NLR of 4 for prognosis might be effective surrogate markers in nivolumab treatment.