The National Institute for Health and Care Excellence (Nice) has approved a new immunotherapy drug for adults with aggressive stomach cancer that has not spread extensively and can be surgically removed. Durvalumab, marketed as Imfinzi and manufactured by AstraZeneca, is expected to benefit an estimated 1,500 people annually in England under the NHS.
Helen Knight, director of medicines evaluation at Nice, said the decision addresses an urgent need: “Stomach cancer is a devastating disease with high rates of recurrence after surgery, so there is an urgent need for treatments like durvalumab that meaningfully extend both the length and quality of patients’ lives.” The drug is administered as part of a perioperative treatment plan — used before and after surgery — initially combined with a specific chemotherapy regimen known as FLOT (fluorouracil, leucovorin, oxaliplatin and docetaxel), and then as a standalone therapy after surgery.
Sheena Dewan, executive director at Stomach Cancer UK, described the approval as transformative. “This is the first major advance in curative-intent treatment for stomach cancer in nearly a decade,” she said. “Adding immunotherapy to perioperative chemotherapy offers a real opportunity for lower recurrence and longer survival. For too long, patients have been enduring the dual burden of life-altering surgery and high rates of recurrence. This treatment gives individuals and families living with the constant fear that the cancer will return a meaningful opportunity for more time with loved ones, more time at work and more time to live well beyond treatment and even cure.”
How the immunotherapy works
Durvalumab is an immunotherapy drug that harnesses the body’s own immune system to fight cancer. It works by blocking a protein called PD-L1, which cancer cells can use to evade detection by immune cells. By binding to PD-L1, durvalumab prevents it from interacting with two receptors on T-cells — PD-1 and CD80. This effectively releases the biological “brakes” on the immune system, allowing T-cells to recognise and attack cancer cells more effectively. The drug is given by intravenous infusion every four weeks.
This mechanism marks a shift from traditional chemotherapy, which directly kills rapidly dividing cells, to a more targeted approach that enlists the patient’s own defences. While effective, durvalumab can cause side effects, including immune-mediated reactions that can affect various organs, as well as fatigue, cough, shortness of breath and gastrointestinal issues.
Clinical trial results
The approval is based on evidence from the MATTERHORN Phase III trial, which compared durvalumab plus FLOT chemotherapy against chemotherapy alone. Patients receiving the combination experienced an average of just over 40 months before their cancer progressed (event-free survival), compared with just over 32 months for those on chemotherapy alone — a gain of roughly eight months. One analysis showed a 29% reduction in the risk of disease progression, recurrence or death.
Overall survival also improved. In the trial, 68.6% of patients taking durvalumab survived for three years, compared with 61.9% on standard chemotherapy. A final overall survival analysis found that the Imfinzi and FLOT perioperative regimen reduced the risk of death by 22% compared with chemotherapy alone.
Nice used a streamlined assessment process for durvalumab, which allowed for a faster decision and quicker patient access. This approach is increasingly used for high-impact treatments backed by strong clinical evidence.
Stomach cancer in the UK
According to Cancer Research UK, stomach cancer — also called gastric cancer — occurs when abnormal cells in the stomach start to grow and divide uncontrollably. Common symptoms include difficulty swallowing, unexplained weight loss, indigestion, feeling and being sick, and dark stools. Around 6,800 new cases are diagnosed in the UK each year, making it the 18th most common cancer in the country.
Survival rates remain poor. Generally, about 20% of stomach cancer patients in the UK survive for five years or more, though this varies significantly by stage: around 65% of patients diagnosed at Stage 1 survive five years, while there are no five-year survival statistics for Stage 4. Ten-year survival is around 16.1%. Stomach cancer is known for high rates of recurrence after surgery, contributing to its poor long-term outlook.
Risk factors include age, diet (low in fruit and vegetables, high in salt), smoking, infection with Helicobacter pylori, and family history. Notably, 54% of stomach cancer cases in the UK are considered preventable. A report from January 2024 indicated that the UK has some of the worst cancer survival rates in the developed world for several cancers, including stomach cancer, ranking as low as 28th out of 33 comparable countries for five-year survival.
Durvalumab is already approved for other cancers, including lung and bladder cancer, and globally was AstraZeneca’s second best-selling drug in 2025, generating $6 billion. Separately, Scotland was the first part of the UK to approve zolbetuximab, another drug for advanced stomach cancer, in January 2026, used in combination with chemotherapy.