Jack Georgakis was able to resume his active lifestyle, including martial arts, after taking part in a clinical trial with immunotherapy at MSK that helps prevent stomach and esophageal cancer from coming back after surgery.
A clinical trial led by researchers at Memorial Sloan Kettering Cancer Center (MSK) has demonstrated a powerful new approach to help prevent cancer from coming back after treatment for stomach cancer, cancer of the lower portion of the esophagus, and gastroesophageal junction (GEJ) cancer.
The Matterhorn Phase 3 clinical trial, led by Chief of Gastrointestinal Medical Oncology Yelena Janjigian, MD, was conducted at hospitals around the world.
The results offer new hope to people facing this diagnosis, which is the fifth most common cancer worldwide, with 1.7 million new patients diagnosed in 2022. Stomach cancer (also known as gastric cancer) and esophageal GEJ cancer are also the fifth highest leading cause of cancer mortality, with approximately 1.2 million deaths expected globally in 2025.
Using Immunotherapy To Help Prevent Stomach and Esophageal Cancer From Recurring
In the U.S., people with localized stomach and esophagus/GEJ cancer (stages 2, 3, and 4a) are usually treated with chemotherapy before and after surgery. The chemotherapy regimen is called FLOT and includes 5-fluorouracil, leucovorin, oxaliplatin, and docetaxel.
However, stomach and esophageal cancer often recurs despite these efforts, and many people face a poor outlook.
In the Matterhorn clinical trial, the risk of cancer coming back was significantly reduced by strengthening the standard treatment with the addition of a form of immunotherapy called a checkpoint inhibitor. This immunotherapy works by “unmasking” cancer cells, which makes them easier for the patient’s own immune system to identify and destroy.
MSK Chief of Gastrointestinal Medical Oncology Yelena Janjigian
The checkpoint inhibitor used in the trial is durvalumab (IMFINZI), made by AstraZeneca.
“For gastroesophageal cancer patients to go through surgery and chemo, it’s devastating to have a recurrence of the cancer,” says Dr. Janjigian. “This trial shows that adding immunotherapy to chemo before and after surgery can dramatically improve the chance that cancer won’t return.”
“The patients were able to have successful surgery,” Dr. Janjigian adds, “without compromising safety. And the chance of complete disappearance of the cancer — known as complete response — was higher with durvalumab.”
She concludes that “the results from the trial support this innovative regimen as a new global standard of care for these patients.”
The results were simultaneously published in June 2025 in the New England Journal of Medicine and at the largest U.S. cancer conference, ASCO (American Society of Clinical Oncology), where it was featured as a Plenary Session. This is a major annual presentation where the most important and practice-changing cancer research studies are unveiled to doctors and the public worldwide.
The Successful Treatment of One’s Patient’s Esophageal Cancer at MSK
Jack Georgakis was stunned when he learned in his mid-30s that he had GEJ, which is cancer that develops where the esophagus (food pipe) meets the stomach.
A native New Yorker who lives in Brooklyn, he says he’s always on the go at his family business or pursuing high-octane hobbies that include “racing cars, riding motorcycles, skiing, and working out at the gym.”
He recalls that when he began experiencing difficulties swallowing, he was initially misdiagnosed. But when cancer was eventually discovered, “I came to MSK to do my due diligence,” he says. “At my first appointment, I fell in love with the whole team and the facility.”
He says he was particularly impressed that “any question I ever had, I never felt alone. There is such a huge learning curve with cancer. But the MSK team was so good with that.”
“I didn’t know much about immunotherapy,” says Jack. “But I’m Greek, and the terminology made sense to me — you’re using the immune system to fight the cancer.” When Dr. Janjigian explained the clinical trial, “I was all in,” he says.
He is very grateful to thoracic surgeon Daniela Molena, MD, who performed minimally invasive surgery to reduce the impact on his body. “Instead of a big scar, all I have is two ‘bullet holes,’ ” Jack says with a laugh.
As part of his recovery, Jack has had to change his eating patterns dramatically, including eating smaller, more tightly controlled meals.
He credits his sense of humor with helping him cope. “We Greeks have a saying: ‘Not all good comes without something bad, and not all bad comes without something good.’ ”
“I’ve struggled with my weight before,” he says, “but now I’m the lightest I’ve been in my life. I like to say I got a free bariatric weight-loss surgery along with the cancer surgery.”
Key Takeaways From the Matterhorn Clinical Trial for Stomach Cancer
Trial Design
The Matterhorn clinical trial involved 948 participants:
- Half received the FLOT chemotherapy regimen plus immunotherapy.
- Half received only the FLOT chemotherapy regimen.
- Participants underwent surgery four to eight weeks after beginning treatment.
Trial Results
One major goal of the trial — known as an endpoint — is “event-free survival.” “Event-free survival means the cancer has not come back,” Dr. Janjigian explains. “Not just that you’re alive and living with cancer. It means you don’t have cancer.”
At two years, 67.4% of the group who received immunotherapy remained event-free, compared with 58.5% of the group who did not receive immunotherapy.
“Adding immunotherapy to chemotherapy significantly improved event-free survival,” Dr. Janjigian says.
She notes that a secondary endpoint called “overall survival” will be reported in 2026 after sufficient time has passed to give an accurate assessment. “Currently a strong overall survival trend was observed in favor of the immunotherapy-based regimen,” she says.
Trial Safety and Side Effects
FLOT and immunotherapy can have side effects, but the risk of serious side effects is relatively low and not increased with the addition of durvalumab. Side effects include nausea, vomiting, diarrhea, and low white blood cell count, which affected some people in the trial.
However, “no new safety concerns were identified,” says Dr. Janjigian, meaning that the combination of the chemo and immunotherapy did not make any toxicities worse and did not compromise chances of surgery.
How the Matterhorn Clinical Trial Helped People Globally, Including in Asia
Dr. Janjigian stresses that a key component of the trial was its global reach. Patients took part in the trial at 147 study centers in 20 countries.
“People in other countries want to know if the results are applicable to them,” Dr. Janjigian explains. “That’s why it’s so important that the trial took place in South America, Europe, North America, and across parts of Asia, including Korea and Japan.”
“In many parts of Asia,” Dr. Janjigian adds, “these cancers are mostly treated with surgery — they don’t use FLOT as much. So getting doctors who took part in this trial to use FLOT and immunotherapy is a real paradigm change that we believe will help people.”
This new immunotherapy option also improves the outlook for younger people with cancer. There has been an alarming rise in cancers among people under 50 — including stomach and esophageal cancers.
“We’re seeing more and more young people in our clinics,” says Dr. Janjigian, “and that includes people with GEJ cancers and those of the esophagus.”
Setting MSK Apart
For Jack, this groundbreaking trial has allowed him to return to his active lifestyle. He says, “I’ve even added another hobby — Brazilian jujitsu,” the intensely physical and demanding martial art.
Jack says he’s glad he sought out MSK for its innovation and expertise.
“At MSK, you can see the compassion and the dedication to treating cancer,” he says. “I tell people you don’t go to a fruit store for steaks. Treating cancer is MSK’s business. This is what they do. And they are the best at it.”
The Matterhorn clinical trial was sponsored by AstraZeneca. Dr. Janjigian’s disclosure is available online.