AACR Annual Meeting 2026

At the AACR Annual Meeting 2026 in San Diego, Dr Alberto Giovanni Leone from Fondazione IRCCS Istituto Nazionale dei Tumori presented the final results of cohort 2 of the INFINITY trial on behalf of the GONO investigators in a plenary session.

The INFINITY trial was a multicenter phase II study investigating a chemotherapy-free immunotherapeutic strategy for patients with resectable MSI-high gastric or gastroesophageal junction adenocarcinoma.
Previously reported data from cohort 1 of the INFINITY trial demonstrated that a short course of neoadjuvant dual immune checkpoint blockade with tremelimumab plus durvalumab (STRIDE regimen) administered over three months, followed by curative-intent surgery, resulted in substantial pathological tumor regression. Specifically, the pathological complete response rate reached 60%, while major pathological response was observed in 80% of treated patients.

Cohort 2 of the study was therefore specifically designed to evaluate the feasibility of a non-operative management (NOM) strategy in patients achieving a clinical complete response (cCR) following neoadjuvant dual immune checkpoint blockade.

Patients received three months of treatment with the STRIDE regimen. Those achieving a cCR entered a structured NOM program consisting of intensive multimodal surveillance every 12 weeks for two years. The primary endpoint of the study was the two-year cCR rate, while secondary endpoints included overall survival (OS), progression-free survival (PFS), and gastrectomy-free survival (GFS).

A total of 18 patients were enrolled, with 17 evaluable for efficacy analyses. Among them, 13 patients (76%) achieved a clinical complete response and initiated the NOM strategy. Only one patient developed a locoregional recurrence during surveillance, which was successfully managed with salvage surgery.
At a median follow-up of 27.1 months (IQR 25.6–32.1), the study demonstrated highly encouraging long-term outcomes. The two-year clinical complete response rate was 71%, while 24-month progression-free survival and overall survival reached 94.1% and 100%, respectively.

Overall, the final results of cohort 2 of the INFINITY trial suggest that a short course of dual immune checkpoint blockade can induce durable complete responses in a meaningful proportion of patients with MSI-high gastric or gastroesophageal junction adenocarcinoma. The data support the feasibility of a non-operative management approach in carefully selected patients treated within experienced multidisciplinary programs with rigorous surveillance protocols.