Updated: 5 days ago
Medically reviewed by Dr . Wang
Key Takeaways |
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Introduction
A stomach cancer report showing claudin-18 isoform 2 (CLDN18.2) may open a treatment discussion, but the word “positive” needs context. This guide explains what the report measures, why treatment cut-offs differ, and which questions to take to your oncologist.
What Is CLDN18.2 in Stomach Cancer?
CLDN18.2, short for claudin-18 isoform 2, is a protein that can act as a treatment target. It normally helps form connections between cells in the stomach lining. Some gastric cancers retain this protein, making it a target for medicines designed to recognise it.
A biomarker is a measurable feature that can help guide care.
For this biomarker, a pathologist examines a tissue sample using immunohistochemistry (IHC): a laboratory staining method that shows protein expression. The stain’s strength and the proportion of tumour cells showing it help classify the result.
This is a protein-expression test. A positive finding does not, by itself, mean the cancer is inherited. Testing for inherited cancer risk answers a different question.
What Should We Look for on the Report?
Ask for the complete pathology report, including the test method and staining details.
Report field | What it tells you |
Percentage of stained tumour cells | The proportion meeting the stated staining criteria in the tested sample. |
Staining intensity | How strongly the cells stain; this is not the cancer stage. |
Assay or antibody used | Which laboratory test generated the result. |
Tissue date and site | When the sample was taken and which tumour area was sampled. |
Interpretation and cut-off | Which definition the laboratory used for “positive” or “negative”. |
These details help the treating team assess whether the result is suitable for the particular treatment being considered.
Table of Content
How Common Is a Positive CLDN18.2 Stomach Cancer Result?
The proportion depends on the cut-off and the population tested. A pooled analysis of screening for the SPOTLIGHT and GLOW trials reported the following:
Finding | Result | Source |
Patients meeting the zolbetuximab biomarker definition | 38.4%: 1,730 of 4,507 screened patients with valid IHC results | Shitara et al., Gastric Cancer, 2024. |
Definition used in that analysis | At least 75% of tumour cells with moderate or strong membrane staining | Same pooled analysis. |
This estimate describes a selected advanced gastric/GEJ cancer screening population. It does not describe every stomach cancer population or the proportion eligible for CAR-T.
Why Do CLDN18.2 Stomach Cancer Treatments Use Different Cut-Offs?
A cut-off belongs to a particular treatment, test and evidence base. There is no universal CLDN18.2 “positive” result that automatically qualifies someone for every targeted treatment.
The distinction matters when comparing zolbetuximab’s approved testing criteria with the entry criteria used in the pivotal satri-cel study.
Treatment and evidence | CLDN18.2 definition | How to interpret it | Source |
Zolbetuximab: US prescribing information | At least 75% of tumour cells show moderate or strong membrane staining, using a test approved by the US Food and Drug Administration (FDA). The approved companion diagnostic is the VENTANA CLDN18 (43-14A) RxDx Assay. | This is a treatment-linked approved definition. Other clinical eligibility requirements still apply. | FDA approval notice and prescribing information. |
Satri-cel: pivotal CT041-ST-01 trial | At least 40% of tumour cells, with staining intensity at least 2+, meaning moderate or strong, using the trial’s clone 14F8 assay. | This is a trial entry criterion. It must not be presented as a verified current commercial eligibility rule. | Qi et al., The Lancet, 2025. |
A result classified as negative for zolbetuximab may still show CLDN18.2 below its cut-off. Other treatment criteria may warrant discussion, but percentages from different assays cannot automatically establish eligibility. This inference follows from the definitions above.
VERIFY — satri-cel commercial testing requirements: Confirm the current Chinese prescribing information, accepted assay and treating centre’s requirements before using a report to assess access. The published trial threshold alone is insufficient.
Could Another Biopsy Give a Different Result?
Yes. Results can differ between tumour samples and can change during treatment. A published study documented changes in CLDN18.2 expression during chemotherapy and immunotherapy; its findings do not mean every patient’s result will change.
An older result should be reviewed in context. Ask whether the existing tissue can be reassessed and whether another biopsy would change management enough to justify the procedure. Do not assume that an old report is automatically unusable.
Contact Chinese Hospitals Directly, Using a Trusted Facilitator
If your report shows CLDN18.2, contact Chinese hospitals through a trusted facilitator to ask whether newer options apply.
Which CLDN18.2 Stomach Cancer Treatments Are Available Today?
Zolbetuximab and satri-cel target the same biomarker through different approaches and are used in different treatment settings.
Zolbetuximab is a monoclonal antibody, a laboratory-made antibody that recognises a particular target. CAR-T treatment uses a patient’s immune T cells, modified in a laboratory to recognise a target on cancer cells.
Before discussing either, check human epidermal growth factor receptor 2 (HER2) status: the approved uses below require HER2-negative disease.
Option | Relevant approved use | What the approval establishes | Source |
Zolbetuximab, also called Vyloy | For adults with HER2-negative, CLDN18.2-positive gastric/GEJ adenocarcinoma that is locally advanced and cannot be surgically removed, or has spread. Used with fluoropyrimidine- and platinum-containing chemotherapy as first-line treatment. | The FDA approved this combination on 18 October 2024. First-line means the initial systemic treatment for that advanced setting. | FDA. |
Zolbetuximab in China | NMPA has also announced approval with chemotherapy in the relevant first-line setting. | China approval exists; an individual hospital must confirm the applicable label and practical availability. | NMPA announcement, 11 June 2025. |
Satri-cel in China | CLDN18.2-positive, HER2-negative advanced gastric/GEJ adenocarcinoma after failure of at least 2 previous treatment lines. | NMPA has announced approval for this later-line use. A positive biomarker alone does not establish suitability. | NMPA announcement, 22 June 2026. |
A China approval does not mean a patient needs to travel. Zolbetuximab is also authorised in Australia and Singapore. Ask your local team about the applicable indication, availability and funding.
For families in Malaysia, Thailand, Vietnam, Indonesia and New Zealand, ask the oncologist or hospital pharmacy to confirm current national authorisation and local access. Ask the insurer separately whether it covers the biomarker test and the proposed treatment, and whether pre-authorisation is required.
If a trial is suggested, request its exact name, registration and eligibility criteria. Approval of one CLDN18.2-targeted product does not establish approval of every treatment aimed at that protein.
What Are the Risks and Side Effects of CLDN18.2 Stomach Cancer Treatments?
A biomarker match does not ensure that benefits will outweigh harms. These treatments do not work for everyone; risks differ between therapies.
Treatment | Risks to discuss | Practical implication | Source |
Zolbetuximab with chemotherapy | Nausea and vomiting can be severe. Serious allergic and infusion-related reactions can occur. | Ask about anti-sickness medicines, infusion monitoring and the additional risks of the chemotherapy regimen. | Current US prescribing information. |
CAR-T, including satri-cel | Cytokine release syndrome (CRS) is an inflammatory reaction that can cause fever, low blood pressure and breathing difficulty; it can be severe. | Treatment requires specialist assessment and a plan for monitoring and managing complications. | NCI CAR-T safety information. |
Satri-cel treatment pathway | Low blood cell counts were reported in the pivotal study. | Ask the centre to explain infection precautions, blood monitoring and the complete risks of preparative chemotherapy and cell treatment. | Qi et al. |
What Can a Positive Result Not Tell Us?
A positive result alone cannot establish how much an individual will benefit. The full medical case still guides treatment decisions.
Ask the oncologist to explain the expected benefit for the proposed treatment in the patient’s situation, the alternatives and how response would be assessed. A shared target does not make zolbetuximab and satri-cel interchangeable.
When Should We Discuss a CLDN18.2 Stomach Cancer Result With Our Oncologist?
Discuss it when the report arrives or the treatment plan is being reconsidered. There is no need to wait until international travel is being planned.
Take the full pathology report and ask:
Which treatment decision could this result change?
What percentage of tumour cells meets the required staining intensity?
Was the test appropriate for the treatment being considered?
Does the tissue sample still answer the current clinical question?
How do HER2 status and the rest of the medical case affect the options?
What is available locally, and what would a second opinion add?
A biomarker result itself is not an emergency. Symptoms still need attention: vomiting blood or black stools with feeling unwell warrant urgent medical assessment. During an infusion, report breathing difficulty, throat tightness or a sudden reaction immediately. Do not wait for a repeat biomarker test to seek help.
How ChinaCureLink Can Help
ChinaCureLink can help families ask whether a CLDN18.2 result has practical implications for care in China.
Contact Chinese Hospitals Directly, Using a Trusted Facilitator
If your report shows CLDN18.2, contact Chinese hospitals through a trusted facilitator to ask whether newer options apply.
ChinaCureLink, a Medebound HEALTH company, is an independent medical facilitator and patient advocate. We don’t begin with the hospital. We begin with the medical case. We are independent of any one hospital and do not represent only one hospital.
Our support starts with reviewing the diagnosis, pathology, biomarkers and previous treatments before discussing hospital options. We can help coordinate hospital enquiries, arrange an online consultation before travel where available, and support communication and care coordination. Depending on the case, we help match patients with up to three relevant Chinese hospitals and specialists.
Why ChinaCureLink | Source and publishing status |
Physician-founded | Standing ChinaCureLink editorial brief. VERIFY the approved company wording. |
3,000 international patients helped | Standing ChinaCureLink editorial brief. VERIFY the current count, reporting date and whether it refers to ChinaCureLink or the wider Medebound HEALTH organisation before publication. |
The treating medical team decides eligibility and treatment. A facilitator cannot guarantee acceptance or benefit.
Get a Second Opinion Before Fly to China
For suitable cases, ChinaCureLink can then coordinate an online consultation with the specialist to discuss the technical treatment details directly. The purpose is to help the patient understand which treatment option and which specialist center may be most appropriate before making an international treatment decision.
What Patients Say About ChinaCureLink & Medebound HEALTH
China CureLink operates under Medebound HEALTH — an internationally recognized healthcare navigation company incorporated in New York, with operations across North America and Asia-Pacific.
Frequently Asked Questions
Is a Positive CLDN18.2 Stomach Cancer Result Good or Bad?
It may identify a treatment option, but cannot, by itself, establish prognosis or guarantee benefit.
How Common Is a Positive CLDN18.2 Stomach Cancer Result?
In pooled screening for the SPOTLIGHT and GLOW trials, 38.4% met the zolbetuximab threshold. This describes a selected advanced gastric or gastro-oesophageal junction cancer population; rates depend on the test and cut-off.
Can CLDN18.2 Status Change?
Yes. Expression can differ between tumour samples and change during treatment. Ask whether the existing report is suitable for the proposed therapy, and whether reassessing stored tissue or taking another biopsy would change care.
About ChinaCureLink
ChinaCureLink helps patients across the world access the best cancer treatment at China's top hospitals, without the delays, language barriers, and administrative confusion that typically come with seeking care abroad.
We connect patients directly with China's top cancer hospitals, ensuring that from the first case submission through to treatment and follow-up, every step is guided, translated, and coordinated by a team experienced in cross-border patient care.
ChinaCureLink is proudly affiliated with Medebound HEALTH — founded by US physicians, with over 10 years of experience and more than 3,000 patients served worldwide, Medebound HEALTH is recognized by Forbes and it is one of the most trusted patient cross-border concierge service company across North America and the Asia Pacific.
Disclaimer
This article is for informational purposes only and is not medical or financial advice. Treatment eligibility, protocols, and costs vary by individual case — confirm specifics with a coordinator and treating physician before making any decisions.
Numbered, Dated Sources
US Food and Drug Administration. Zolbetuximab approval notice, 18 October 2024. FDA approval notice.
DailyMed / US National Library of Medicine. VYLOY prescribing information, revised August 2026, particularly patient selection and warnings. Current label. Original FDA label: October 2024, FDA PDF.
Shitara K et al. Pooled CLDN18.2 prevalence analysis from SPOTLIGHT and GLOW. Gastric Cancer, published 2 July 2024. Journal article.
Shah MA et al. GLOW trial of zolbetuximab with chemotherapy. Nature Medicine, published 31 July 2023. Journal article.
Qi C et al. CT041-ST-01 randomised trial of satri-cel. The Lancet, published online 31 May 2025; issue 7 June 2025.
National Medical Products Administration, China. Zolbetuximab marketing-approval announcement, updated 11 June 2025. NMPA announcement.
National Medical Products Administration, China. Satricabtagene autoleucel marketing-approval announcement, published 22 June 2026. NMPA announcement.
Therapeutic Goods Administration, Australia. VYLOY registration record; decision 12 March 2025, registration 17 March 2025. TGA record.
Health Sciences Authority, Singapore. March 2025 new-drug approvals; VYLOY approval 6 March 2025. HSA record.
Lim SH et al. Study of changing CLDN18.2 expression during chemo-immunotherapy. Journal for ImmunoTherapy of Cancer, published 29 September 2025.
National Cancer Institute. Biomarker testing for cancer treatment, updated 14 December 2021.
National Cancer Institute. T-cell transfer therapy, updated 5 August 2024. Used for general mechanism and toxicity, not current China approval status.
National Health Service, UK. Vomiting blood, reviewed 18 August 2025.
