Real-world sequential treatment patterns and outcomes in the new era of immunotherapy for advanced gastric cancer in Japan.

[BACKGROUND] We investigated treatment patterns and outcomes in patients with advanced gastric cancer (AGC) after nivolumab first-line therapy approval in Japan in 2021.

[METHODS] This retrospective study used data from the Medical Data Vision database. Treatment patterns were described. Overall time-to-treatment discontinuation (TTD) from the start of each line was estimated.

[RESULTS] Among 11,276 included patients, 1589 received anti-HER2+chemotherapy (Cx) at any line and regarded as HER2-positive AGC (anti-HER2+Cx group). Among the other, 9687 who presumably had HER2-negative AGC, 5722 received nivolumab+Cx at first-line (Nivo+Cx group), and 3965 received Cx alone at first-line (Cx group). Nivolumab+S-1+oxaliplatin (4,104/11,276; 36.4%) was the most common first-line regimen. The most common second-line and third-line regimens were ramucirumab+paclitaxel (PTX) (or NabPTX) (3092/4345; 71.2%) and nivolumab (490/1712; 28.6%). Median overall TTD from start of first-line therapy was 13.3, 10.5, and 6.8 months in anti-HER2+Cx, Nivo+Cx, and Cx groups. Median overall TTD from start of second-line therapy was 6.2, 3.5, and 4.9 months with ramucirumab combination therapy, ramucirumab monotherapy, and other therapies.

[CONCLUSIONS] After first-line nivolumab was introduced for AGC in Japan, treatment patterns remained consistent with Japanese Gastric Cancer Association guidelines. Optimizing sequential therapy, including nivolumab at first-line and ramucirumab combination at second-line, may improve outcomes.