Dual Immunotherapy Avoids Surgery in 70.6% of MSI-H Gastric Cancer Patients

Dual checkpoint blockade with durvalumab and tremelimumab allowed 70.6% of patients with microsatellite instability-high (MSI-H) resectable gastric or gastroesophageal junction adenocarcinoma (G/GEJAC) to avoid surgery in a small cohort of the INFINITY study.

The trial treated MSI-H patients with durvalumab 1500 mg once a month for 3 months along with one 300-mg dose of the CTLA-4 blocker tremelimumab on day 1. In cohort 1, 18 patients proceeded to surgery, with a 60% pathologic complete response rate. In cohort 2, 18 patients were assessed for clinical complete response; if present, they went on to surveillance; if not, they had surgery. Among 17 evaluable patients, 13 (76%) had a clinical complete response and started surveillance, and the other four went to surgery. One patient in the surveillance group had a local regrowth after 4 months, underwent salvage surgery, and remained disease-free. At a median follow-up of 27.1 months, there were no additional progression events. Overall, 12 of the 17 patients (70.6%) were gastrectomy-free at 2 years without additional treatment. Progression-free survival was 94.1%, and all patients were alive.

The lead investigator said the results are very encouraging and that nonoperative management could be a safe and effective strategy for patients achieving a clinical complete response after only 3 months of dual immunotherapy, but the optimal strategy needs to be established in larger randomized trials. The study also calls into question the need for chemotherapy, although dual checkpoint blockade appears to be required for a chemotherapy-free approach to achieve organ preservation. Anti-PD-1 alone is not sufficient; CTLA-4 is needed to expand and reactivate tumor-specific immunity. Three patients had grade 3 adverse events (hyperthyroidism, increased gamma-glutamyl transferase, and colitis) that resolved with steroids. There were no grade 4 events, treatment discontinuation, or deaths.

In a separate area of practice, specialized German oncology clinics combine standard therapy with off-label immunotherapy. A 2024 analysis found that approximately 20-25% of patients had measurable responses to off-label immune-based combination treatments, while about 40% of cases experienced disease stability. Serious immune-related side effects occur in about 10-15% of patients, a rate consistent with figures reported in major international guidelines such as ESMO and ASCO. Off-label immunotherapy includes checkpoint inhibitors such as nivolumab or pembrolizumab, dendritic cell vaccines, oncolytic virotherapy, targeted agents and antibody-drug conjugates, and physical or regional methods such as hyperthermia. At one German clinic, case series of rare and advanced tumors report median overall survival of 22 to 38 months, with 2-year survival rates of 39% to 81%, depending on the diagnosis and treatment sequence.

For patients considering cancer immunotherapy in Germany, hospital rankings can serve as a useful starting point. They help understand which centers are large and well-equipped, but they rarely answer which hospital is right for a specific diagnosis. Rankings cannot reflect a team's experience with a particular cancer type; specialization matters more than overall reputation. Immunotherapy clinics in Germany often re-evaluate biopsy samples to confirm histology and, when relevant, receptor status or basic biomarkers. Biomarkers clarify how the tumor behaves and whether treatments such as immunotherapy may be considered. Eligibility depends on tumor biology and overall health. Doctors also consider autoimmune conditions, chronic infections, and other factors that may affect safety. Choosing a cancer hospital is less about technology and more about the team's ability to support the patient throughout treatment, including multidisciplinary tumor board, access to pathology and molecular testing, monitoring of immune-related side effects, and structured follow-up. A structured approach includes creating a shortlist, checking specialization, requesting a structured case review, comparing monitoring and logistics, and deciding based on medical fit.