Immunotherapy for patients with stage IV metastatic stomach cancer has already become a standard of care. But this is the first time it has been confirmed that immunotherapy can also significantly improve survival for early gastric cancer patients who are eligible for curative surgery.
On the 6th (local time), Yelena Y. Janjigian, an oncologist at Memorial Sloan Kettering Cancer Center (MSKCC), met with Korean reporters at European Society for Medical Oncology Asia (ESMO ASIA 2025) in Singapore and said this.
Professor Janjigian is the principal investigator who led AstraZeneca's global phase 3 trial MATTERHORN. The trial evaluated whether adding an immunotherapy agent to standard chemotherapy (FLOT, fluorouracil, leucovorin, oxaliplatin, and docetaxel) improves survival in patients with early gastric and gastroesophageal junction (GEJ) adenocarcinoma without distant metastasis. The immunotherapy used in the study was Imfinzi (ingredient name durvalumab).
She explained the study background, saying, Recently, not only in the United States and Europe but also in Asia, the perception is growing that cure with surgery alone is difficult. That is why additional treatment strategies are needed. She added, This study showed that giving combined chemo-immunotherapy before surgery and continuing the same regimen after surgery leads to improved survival.
At the congress, Professor Janjigian also reported that this combination therapy showed strong efficacy in patients from Korea, Japan, and Taiwan who took part in the trial. She said, The U.S. Food and Drug Administration (FDA) recently approved the use of this regimen for patients with resectable gastric and gastroesophageal junction adenocarcinoma, adding, It is very important to harmonize treatment strategies across Asia, the United States, and Europe. Because gastric cancer is diagnosed in about 1.2 million people worldwide every year, the socioeconomic disease burden is high.
In the study, the chemo-immunotherapy combination demonstrated superiority over chemotherapy alone in key endpoints including pathologic complete response rate (pCR), event-free survival (EFS), and overall survival (OS). Professor Janjigian said, About 19% of patients who received the combination had their cancer disappear completely, adding, This is the first time such numbers have been achieved with chemo-immunotherapy without radiation.
The combination did not reduce patients' fitness for surgery. She said, Patients and clinicians worry that delaying surgery might make surgery harder later, but in reality it's the opposite, adding, By strengthening the immune system with the combination, anti-cancer control is maintained even after surgery. She continued, In the study, after 1 to 2 cycles of preoperative combination therapy, many patients rapidly improved physically, such as with rising albumin levels, and tolerated surgery better.
The effect appeared similar across all age groups. She said, Participants ranged from 18 to 84 years old, and outcomes were favorable even among those 65 and older. However, she noted, Asian patients had a higher incidence of leukopenia, especially neutropenia, than patients in other regions due to metabolic characteristics.
For this reason, clinicians in Asia are widely adopting a strategy of proactively using leukocyte growth factor injections from the outset. Professor Janjigian explained, For patients with poor performance status, slightly lowering the initial dose of FLOT (standard chemotherapy) is also an option, and because the combination of chemotherapy and immunotherapy is the key to tumor shrinkage, adjusting the initial FLOT dose is not a major problem. If followed by IV hydration or leukocyte growth factor injections, most patients tolerate the treatment course well.
She said the combination is particularly effective before surgery. That is because the immune system needs the tumor to remain to "learn" more antigens and maximize T-cell (immune cell) responses. Professor Janjigian said, For diffuse-type gastric cancer or signet-ring cell carcinoma, we recommend preoperative combination therapy even at stage II (T2).
She added, Asian patients have traditionally had more "distal stomach" cancers associated with Helicobacter infection, making recovery relatively easier even after resection, but proximal (upper stomach near the esophagus) and gastroesophageal junction (GEJ) cancers have been increasing recently, and Because recovery is much more difficult after surgery for these patients, it is important to shrink the tumor with combination therapy before surgery.