372. TREATMENT USING NIVO+CHEMO OR NIVO+IPI FOR UNRESECTABLE/RECURRENT ESOPHAGEAL SQUAMOUS CANCER IN OUR INSTITUTE

Abstract Introduction Currently, regarding stage IVB esophageal cancer treatment, the esophageal cancer treatment guideline in JAPAN was revised in 2022 based on the results of two phase III trials, KN590 and CM648, and Nivolumab+Chemo and Nivolumab+Ipilimumab would be used as 1st line treatment. Subject NIVO+Chemo19NIVO+Ipilimumab (IPI)17 Before February 2024, a total of 160 cases of unresectable/recurrent esophageal squamous cell carcinoma have been treated using IO, IO+Chemo, and IO+IO at our institute. 19 cases were treated with NIVO+Chemo and 17 cases were treated with NIVO+IPI as the 1st line treatment. We examined the treatment backgrounds and outcomes of these subjects. Result Regarding patient characteristics, median age was 66/65 years in NIVO+Chemo group/NIVO+IPI group, male to female ratio was 18:1/15:2, PS0/1 was 14/5 cases in NIVO+Chemo, and 16/1 cases in NIVO+IPI. Pre-treatment status (primary unresectable/recurrent/other) were 13/5/1 in NIVO+Chemo, and 4/12/1 in NIVO+IPI. The presence/absence of post-treatment was 12/7 cases in NIVO+Chemo and 10/7 cases in NIVO+IPI. The presence/absence of irAEs was 5/14 cases in NIVO+Chemo, and 15/2 cases in NIVO+IPI. ORR was 52.6%, and median OS was 782 days, and median PFS was 190 days in NIVO+Chemo group, and 52.9%/544days/138days in NIVO+IPI group. Consideration Both the NIVO+Chemo and NIVO+IPI groups at our facility had longer OS and PFS than previously reported. In particular, the response rate of NIVO+IPI was as high as that of the NIVO+Chemo group, and this is thought to be since many cases of postoperative recurrence with small tumor volumes were enrolled in NIVO+IPI group. We believe that it is important to distinguish between IO/IO and IO/CHEMO as a treatment strategy for unresectable/recurrent esophageal squamous cell carcinoma.