The overall safety and short-term efficacy of nivolumab plus ipilimumab for advanced esophageal squamous cell carcinoma.

Abstract

329 Background: Although nivolumab plus ipilimumab (Nivo+Ipi) is strongly recommended as 1st-line treatment for patients with advanced esophageal squamous cell carcinoma (ESCC), tumor proportion score (TPS) should be considered. Despite the efficacy, patients who received Nivo+Ipi often experienced serious immune related adverse events (irAEs). However, there are few data on safety and short-term efficacy of Nivo+Ipi in real world. Methods: We retrospectively collected data of pts who received Nivo+Ipi for advanced ESCC between May 2022 to July 2023 in the National Cancer Center Hospital. We evaluated adverse events by CTCAE v5.0 and multivariate analysis using a logistic regression model. estimated overall response rate (ORR) by RECIST v1.1 and progression-free survival (PFS). Results: Thirty pts were subjects in this study. The characteristics were as follows: median age (range): 63.5 (36-80) years, male/female: 24/6, metastatic/recurrent: 3/27, ECOG PS 0/1≤: 16/14, PD-L1 TPS 1%≤: 17, number of organs with metastases 1/2≤: 13/17, treatment-line 1st/2nd≤ 6/24 Median follow-up time was 5.0 months (mo) (reverse Kaplan-Meier, 95%CI; 3.0-8.3 mo). Any grade and grade 3≤ irAEs were observed in 12 (40.0%) and in 5 pts (17.9%), respectively. In grade 3≤ irAEs, AST/ALT elevation (n=2, 7.1%), adrenal insufficiency (n=1, 3.6%), pneumonitis (n=1, 3.6%), myositis (n=1, 3.6%), encephalopathy (n=1, 3.6%), stevens-Johnson syndrome (n=1, 3.6%) were reported. The pts who received systemic steroid therapy was 8 pts (28.6%). Two pts received high-dose steroid with methyl-prednisolone, 1 g/body for 3 days, four pts needed steroid therapy with prednisolone, 1-2 mg/kg and two pts added mycophenolate mofetil. No treatment-related deaths were reported. For the pts who received Nivo+Ipi as a first-line treatment (n=6), 3 pts (50%) achieved partial response and 2 pts (33.3%) had stable disease. 6-mo PFS rate of the 1st line pts was 63%. For the pts who received Nivo+Ipi in later-line, the ORR and the median PFS were 33.3% and 2.6 mo (95%CI; 1.4-3.9 mo), respectively. Fifteen pts received subsequent systemic therapy, which consisted of taxane (12 pts), fluoropyrimidine plus platinum (2 pts) and 1 pt continued Nivo+Ipi beyond progression. Conclusions: Our study may demonstrate a consistent incident of irAEs in pts who received Nivo+Ipi in the real world, compared to the results of the CheckMate 648. Despite of the short time of follow-up period, 1st-line treatment with Nivo+Ipi appeared to be more efficacious than Nivo+Ipi used as a later-line treatment.