Title: P61-5 Examination of patients with advanced non-small cell lung cancer (NSCLC) responding to nivolumab monotherapy over 1 year
Abstract: Nivolumab, a PD-1 immune-checkpoint-inhibitor antibody, was approved six years ago as 2nd line therapy for advanced NSCLC. The 5-year survival rate for NSCLC is 13.4% according to phase III trials Checkmate 017 and 057. Although some cases responding favorably to long-term treatment with nivolumab have been reported, few studies have investigated the reasons for discontinuation of nivolumab. We included 29 patients with advanced NSCLC who had received treatment with nivolumab from January 2016 through April 2019 and retrospectively analyzed clinical features of 8 patients administered nivolumab monotherapy over 1 year. The patients included 5 men and 3 women (median age at diagnosis was 71.5 years [66-80 years]). All patients had a smoking history (3-60 packyear). Histological type of the cancer was adenocarcinoma and squamous cell carcinoma in 4 cases each; EGFR mutation was found in 2 cases. The ECOG-PS at the onset of treatment was 0, 1, and 2 in 5, 1, and 2 cases, respectively. The line of treatment was 2nd in 7 cases and beyond 4th in 1 case. PR and SD in 5 and 3 cases, respectively, was the best over-all response. Median duration of treatment was 40 months (14-69 months), with 2 cases currently under continued nivolumab treatment. Reasons for discontinuation of nivolumab were progressive disease (increase in primary lesions and new metastatic lesions [lung field] each one), appearance of another cancer (prostatic carcinoma, ureter cancer, or lung cancer with a different histological type from the primary lesion), decreased physical strength not due to lung cancer in 2, 3, and 1 cases, respectively. The median progression-free survival among the 29 cases was 4.0 months and median overall survival was 28.0 months, with a 24.1% chance of surviving 5 years. Our findings indicate that the appearance of another cancer was the problem rather than cancer progression itself.