AstraZeneca PLC (LSE:AZN) has reported encouraging results from a late-stage trial of its cancer immunotherapy Imfinzi, which significantly extended the time patients with early-stage bladder cancer lived without their disease coming back or getting worse.
The data, released Friday, come from the company’s phase III POTOMAC trial and mark a potential breakthrough for patients with high-risk non-muscle-invasive bladder cancer, a form of the disease that accounts for the majority of bladder cancer diagnoses and has a stubborn tendency to return.
The trial tested whether adding Imfinzi to standard treatment, a vaccine-like bladder therapy known as Bacillus Calmette-Guérin, or BCG, would help keep the disease at bay. It did.
One year of Imfinzi, combined with both induction and maintenance courses of BCG, delivered what AstraZeneca called a “statistically significant and clinically meaningful” improvement in disease-free survival compared with BCG alone.
Maria De Santis, head of uro-oncology at Charité Hospital in Berlin and one of the trial’s lead investigators, said the results pointed to a real benefit for patients.
“These exciting data show that adding one year of durvalumab to the current standard treatment significantly extends the time patients live without high-risk disease recurrence or progression,” she said.
Non-muscle-invasive bladder cancer (NMIBC) is a relatively early stage of the disease, where the tumour remains on the surface of the bladder and hasn’t yet penetrated the muscle wall.
Although treatable, around 80% of patients see their cancer return, and many eventually need their bladder removed.
Imfinzi, also known by its generic name durvalumab, works by helping the immune system recognise and attack cancer cells. It does this by blocking a protein called PD-L1, which many tumours use to hide from immune defences.
The POTOMAC study enrolled just over 1,000 patients across more than 120 centres globally. All participants had received surgery to remove visible tumours before treatment began.
Those who received Imfinzi and full BCG therapy fared better, while a second trial arm, where Imfinzi was combined only with the initial BCG course, did not show a benefit.
Cristian Massacesi, AstraZeneca’s chief medical officer, said the results strengthen the company’s position in earlier-stage cancers, where preventing relapse can have the greatest long-term impact.
“The positive results for Imfinzi in the POTOMAC trial represent a significant advance that will potentially allow more patients with early-stage bladder cancer to benefit from this important immunotherapy,” he said.
No new safety concerns were identified, and patients were able to complete their treatment regimens without added complications. Regulatory submissions are planned, and the full results will be shared at an upcoming medical meeting.
Imfinzi is already approved for use in several other cancers, including muscle-invasive bladder cancer, lung cancer, and certain liver and biliary tract cancers.
AstraZeneca is continuing to explore its use in combination with other therapies across a broad range of tumour types.