AstraZeneca PLC [LSE: AZN] received one of its most clinically significant UK regulatory approvals on Thursday, with the National Institute for Health and Care Excellence giving the green light for its immunotherapy drug durvalumab to be used in the treatment of adults with operable stomach cancer on the NHS.

Shares in AstraZeneca were up 0.4% at 13,824 pence in London morning trading following the announcement, a measured but positive market reaction to a development that charity groups and oncologists have described as the first major advance in curative-intent stomach cancer treatment in nearly a decade.

Durvalumab, sold under the brand name Imfinzi, works by helping the body’s own immune system recognise and attack cancer cells, a fundamentally different mechanism from the chemotherapy that has historically formed the backbone of stomach cancer treatment.

Clinical trials showed that adding durvalumab to perioperative chemotherapy, meaning the drug is given both before and after surgery, significantly extended the time before the disease progressed and improved overall survival in patients whose cancer had not spread extensively and could be removed through an operation.

NICE approved the drug specifically for adults whose stomach cancer meets those criteria, meaning it has not spread extensively through the body and remains surgically resectable, giving clinicians a new tool at the stage of treatment where intervention is most likely to achieve curative outcomes.

Helen Knight, director of medicines evaluation at NICE, said there was an urgent need for treatments like durvalumab that meaningfully extend both the length and quality of patients’ lives given the devastatingly high rates of recurrence that characterise stomach cancer even after successful surgery.

Sheena Dewan, executive director at Stomach Cancer UK, described the decision as transformative for patients and families, saying that for too long people had been enduring both the physical burden of life-altering surgery and the constant psychological fear that the cancer would return.

It is estimated that approximately 1,500 patients a year could be eligible to receive durvalumab under the NHS approval, giving the drug a meaningful volume of addressable patients from launch rather than the narrow initial cohorts that can limit the commercial impact of some oncology approvals.

The stomach cancer approval adds to Imfinzi’s expanding portfolio of licensed indications, with AstraZeneca also reporting separately on Thursday that the same drug had produced positive results in a Phase III trial in bladder cancer, reinforcing the breadth of the immunotherapy’s clinical programme across multiple tumour types.

AstraZeneca has been one of the strongest performing large-cap pharmaceutical stocks in Europe over the past three years, driven by a deep oncology pipeline and a series of regulatory approvals across multiple cancer types that have progressively expanded the company’s addressable market and supported premium valuation multiples relative to global peers.