MHRA Approves Catumaxomab for Malignant Ascites

The MHRA has approved catumaxomab, sold as Korjuny, for adults with malignant ascites when standard treatment for their cancer is no longer feasible. That may sound like a narrow regulatory update, but for the people living through it, the issue is painfully concrete: fluid keeps building up in the abdomen, and it often has to be drained again and again. **What this means for patients:** this is not a new cure for cancer. It is a new option that may give some people longer between drainage procedures, which can mean a little less disruption, discomfort and time in treatment rooms.

If you have never come across the term malignant ascites before, you are not alone. It means a build-up of fluid in the abdomen that contains cancer cells. The swelling can be distressing in its own right, and it can make eating, moving and breathing feel harder. Many patients need paracentesis, a procedure in which the fluid is drained, to get relief. This is why the approval matters. The question here is not only whether a medicine treats cancer in the abstract. It is whether it can ease one of the complications that can take over day-to-day life when someone is already dealing with advanced illness.

Catumaxomab is a monoclonal antibody. In plain English, that means it is a lab-made protein designed to attach to a specific target. In this case, the target is a protein called EpCAM, which is found on the surface of certain cancer cells, including cells in ascitic fluid. Once catumaxomab attaches to that target, it helps activate parts of the immune system to attack those cancer cells. So rather than simply removing the fluid after it has built up, the treatment is designed to act on the cancer cells linked to that build-up.

The main study behind the approval involved 258 patients with malignant ascites and EpCAM-positive cancer. These were patients who had no further chemotherapy options or for whom chemotherapy was unsuitable. According to the MHRA, patients who received catumaxomab after paracentesis went about 46 days before needing further drainage, compared with about 11 days for patients treated with paracentesis alone. That is the figure to keep in view. The reported benefit is more time before another drainage procedure is needed. It does not, by itself, mean the medicine cures the cancer, and the announcement does not claim that it does. What it does suggest is a practical gain that many patients and families would recognise immediately: fewer repeat procedures, and more breathing space between them.

The way the treatment is given matters too. Catumaxomab is administered under the supervision of a doctor experienced in treating cancer. It is delivered through a catheter directly into the abdominal cavity as four infusions, with the dose increased at each stage. As with most cancer medicines, there are side effects to weigh up. The common ones listed by the MHRA include nausea, vomiting, diarrhoea, abdominal pain, fever, chills and fatigue. The agency also warns about cytokine release syndrome, which is an inflammatory reaction caused by the immune system being activated. That term sounds daunting, but the important point is simple: this treatment needs close monitoring because the possible benefits come with real risks and discomforts.

There is also a regulatory story behind this decision. The new marketing authorisation was granted on 2 October 2026 to Atnahs Pharma UK Limited. The MHRA said the application was approved under the International Recognition Procedure, which is one of the routes it uses when assessing medicines. **How approvals work:** when a regulator approves a medicine, it is saying that for the group covered by the licence, the expected benefits are judged to outweigh the known risks. It does not mean the medicine is right for every patient, and it does not mean questions about safety disappear once approval is granted.

MHRA interim executive director Julian Beach said malignant ascites can place a considerable burden on people living with cancer, especially when further treatment options are limited. He said the approval gives an additional option that may help patients live longer without needing another procedure to drain fluid from the abdomen. The MHRA also says it will continue to monitor catumaxomab’s safety and is asking healthcare professionals and patients to report suspected side effects through the Yellow Card scheme. The agency said the Summary of Product Characteristics and the Patient Information Leaflet would be published on the MHRA Products website within seven days of the approval. For readers trying to make sense of the headline, the takeaway is clear: catumaxomab adds one more treatment option for adults with malignant ascites, with the clearest benefit being a longer gap before repeat abdominal drainage is needed.