The Scottish Medicines Consortium (SMC) has approved zolbetuximab (brand name Vyloy®) for use on the NHS in Scotland. It is a new targeted treatment developed by Astellas Pharma Ltd. Zolbetuximab is given with chemotherapy and is suitable for advanced cancers that test positive for the Claudin 18.2 biomarker.
Stomach Cancer UK was a patient group stakeholder in the SMC approval process and participated in the Patient and Clinician Engagement (PACE) meeting. This ensured that patient experience and priorities were reflected in the SMC’s decision-making.
What is zolbetuximab?
Zolbetuximab is a new targeted cancer treatment. It is a monoclonal antibody that targets the protein claudin 18.2, which is sometimes abbreviated to CLDN 18.2. It is found on the surface of stomach and GOJ cancer cells in around 40% of people with advanced cancer.
Who can have zolbetuximab?
Zolbetuximab is approved for adults in Scotland who meet all of the following criteria:
- They have stomach or gastro-oesophageal junction adenocarcinoma
- Their cancer is locally advanced but inoperable, or metastatic (stage 4)
- Their cancer is HER2 negative
- Their cancer tests positive for the CLDN 18.2 biomarker
- They are starting first-line treatment (the first treatment after diagnosis) for advanced disease
Zolbetuximab only works on cancer that tests positive for CLDN 18.2, which happens in around 4 in 10 people.
Zolbetuximab is not currently available on the NHS in England because it was rejected by the National Institute for Health and Care Excellence (NICE) on cost grounds. It can be available with private insurance in England.
What testing do you need?
All people in Scotland with inoperable or metastatic (stage 4) stomach or GOJ cancer should be tested for CLDN 18.2 when they are diagnosed, before or as treatment first starts.
The testing is done on the biopsy material, which was taken to diagnose cancer, so a new biopsy is not usually needed. If there is insufficient tissue to perform the test, you may ask for a further biopsy.
In England, CLDN 18.2 testing is not routinely offered on the NHS because zolbetuximab is not approved.
You can ask your cancer team if you can be tested for CLDN 18.2 and discuss what the results mean.
What can zolbetuximab do?
The SPOTLIGHT and GLOW clinical trials added zolbetuximab to chemotherapy. These large international trials found that the combination of zolbetuximab plus chemotherapy improved outcomes compared with chemotherapy alone in people whose cancers were CLDN 18.2 positive.
This included:
- Longer control of the cancer, which can mean longer survival for some patients, resulting in a better quality of life for longer.
- A higher rate of complete response, where cancer could no longer be seen on scans. This was the case for around 10% (one in ten) people, compared to around 3% for chemotherapy alone.
For a small minority of people, a very strong response to treatment with zolbetuximab can open the door to further options, including the possibility of surgery with the intention to cure the cancer. While this does not apply to most patients, it is an important potential outcome for a few.
How is zolbetuximab given?
Zolbetuximab is not given on its own. It is used in combination with standard chemotherapy for advanced stomach and GOJ cancer.
It is given by IV infusion at your cancer treatment centre alongside chemotherapy every three weeks for as long as it is effective and side effects are manageable.
It is most commonly given alongside the CAPOX combination (capecitabine and oxaliplatin) of chemotherapy, although you may receive it with FOLFOX (5-FU and oxaliplatin) if CAPOX is not suitable for you.
Side effects
The most common side effects of zolbetuximab are nausea and vomiting, particularly early on in treatment. This can usually be managed effectively with anti-sickness medicines or by giving the IV treatment at a slower rate. Your cancer team will monitor your side effects closely and adjust your care as needed.
What should you do next?
If you are newly diagnosed in Scotland, you can ask your cancer team about CLDN18.2 testing to see if zolbetuximab could be an option for you. You may wish to print and bring this page to your appointment to help you discuss your options with your oncologist.
If you are being treated in England, your team can explain which treatments are currently available and why zolbetuximab is not routinely offered on the NHS.
The Scottish Medicines Consortium’s advice on zolbetuximab was published on 19 January 2026 (SMC2839). The detailed advice document and the public information summary are both available on their website.
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