Key Clinical Takeaways: 

• Design/Population: This randomized study evaluated neoadjuvant tislelizumab plus chemoradiotherapy versus chemoradiotherapy alone or chemotherapy alone among patients with previously untreated, locally advanced gastric or gastroesophageal junction cancer. 
• Key Outcomes: Among patients who underwent surgery, the addition of tislelizumab to chemoradiotherapy resulted in higher pathologic complete response and major pathologic response rates compared with chemotherapy alone and numerically higher pCR compared with chemoradiotherapy alone, with manageable toxicity. 
• Clinical Relevance: These preliminary results support further investigation of immune checkpoint inhibitor-based neoadjuvant strategies for locally advanced gastric and gastroesophageal junction cancer to improve pathologic response before surgery.

According to phase 2b results from the multicenter, open-label TERRIFIC study, the addition of immunotherapy tislelizumab to neoadjuvant chemoradiotherapy demonstrated promising clinical activity among patients with locally advanced gastric or gastroesophageal junction (G/GEJ) cancer. 

These findings were presented by Jia Wei, MD, PhD, Nanjing Drum Tower Hospital, Nanjing, China, at the 2026 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium in San Francisco, California.

In this randomized controlled study, 60 patients with G/GEJ cancer who received no prior anti-cancer therapy were randomized 2:2:1 to receive either 200 mg of tislelizumab plus chemoradiotherapy consisting of 45 Gy of radiotherapy with SOX or S-1 plus nab-paclitaxel (n = 23), chemoradiotherapy (n = 24) alone, or chemotherapy alone (n = 13) for 3 cycles. Following surgical resection, all patients received 3 cycles of chemotherapy followed by 3 cycles of S-1 as maintenance therapy, with patients in the tislelizumab-containing arm continuing tislelizumab maintenance for up to 12 months. The study’s primary end point was pathologic complete response (pCR). Key secondary end points included major pathologic response and safety.

At analysis, the pCR rate was 34.8% in the tislelizumab plus chemoradiotherapy arm, 0% in the chemoradiotherapy arm, and 25% in the chemotherapy arm. Major pathologic response rates were 65.2%, 15.4%, and 62.5%, respectively. Grade ≥ 3 treatment-related adverse events were reported in 14.3% of patients in the tislelizumab plus chemoradiotherapy arm, in 9.1% of patients in the chemoradiotherapy arm, and in 10.5% of patients in the chemotherapy arm. Any-grade immune-related adverse events were reported in 25% of patients in the tislelizumab plus chemoradiotherapy arm.

“The preliminary results showed that [tislelizumab plus chemoradiotherapy] had higher pCR rate over [chemoradiotherapy or chemotherapy] alone for pts with locally advanced [G/GEJ cancer],” concluded Dr Wei. These results “further confirm the improved efficacy of [immunotherapy] as neoadjuvant therapy for [G/GEJ cancer].” 

Source:

Wei J, Gou H, Yang J, et al. Tislelizumab plus chemoradiotherapy (CRT) versus CRT or chemotherapy (CT) as the neoadjuvant treatment for patients (pts) with locally advanced gastric/gastroesophageal junction adenocarcinoma (GC/GEJC): A multicenter, randomized controlled, open-label, phase IIb study (TERRIFIC). Presented at ASCO Gastrointestinal Cancers Symposium. January 8 - 12, 2026; San Francisco, California. Abstract 286