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Claudin 18.2 is a tight-junction protein exposed on stomach cancer cells. Zolbetuximab requires at least 75 percent of tumour cells to stain moderately or strongly, the strictest expression threshold in any current label.
Zolbetuximab (Vyloy) is labelled with fluoropyrimidine and platinum chemotherapy for first-line HER2-negative gastric or GEJ adenocarcinoma whose tumours are CLDN18.2 positive as determined by an FDA-approved test; the SPOTLIGHT and GLOW trials and the VENTANA CLDN18 (43-14A) RxDx Assay define positivity as 75 percent or more of tumour cells with moderate to strong membranous staining. About 38 percent of screened patients met the bar. CLDN18.2 ADCs and CAR-T cells in trials use lower or different cut-offs.
In plain words · A tight-junction protein normally hidden in the stomach lining that becomes exposed in gastric and pancreatic cancers.
If at least three quarters of your stomach cancer cells stain moderately or strongly for claudin 18.2, zolbetuximab can be added to first-line chemotherapy, provided the cancer is HER2-negative. A lower percentage does not qualify under the label, though trials of other claudin 18.2 drugs may accept it. Nausea and vomiting during the first infusions are common and expected.
Written only from the label or guideline text cited on this page. Not medical advice; your own report and the reading your team gives it come first.
75 percent or more of viable tumour cells with moderate to strong membranous CLDN18 staining on the VENTANA CLDN18 (43-14A) RxDx Assay.
“CLDN18.2 positivity (defined as ≥75% of tumor cells demonstrating moderate to strong membranous CLDN18 staining) was determined by immunohistochemistry on gastric or GEJ tumor tissue specimens from all patients with the VENTANA CLDN18 (43‑14A) RxDx Assay performed in a central laboratory.”
VYLOY prescribing information| Threshold | Drug | Cancer | Regulator | Source |
|---|---|---|---|---|
| >= 75% of tumour cells with moderate to strong membranous staining | Zolbetuximab | Claudin 18.2-positive gastric cancer | FDA | label |
| Device | Maker | Indication and sample | Drug | PMA / 510(k) |
|---|---|---|---|---|
| VENTANA CLDN18 (43-14A) RxDx Assay | Ventana Medical Systems (Roche) | Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma - Tissue | Zolbetuximab | P230018 (10/18/2024) |
Matched on the name and aliases of the readout in the title, setting and summary of each trial; a match is a mention, not proof the readout was an entry criterion.
Shares Immunohistochemistry (IHC) and the tags biomarker, surface-antigen.
Shares Immunohistochemistry (IHC) and the tags biomarker, surface-antigen.
Shares Immunohistochemistry (IHC) and the tags biomarker, surface-antigen.
Shares the tags biomarker, surface-antigen.
Shares the tags biomarker, surface-antigen.
Shares the tags biomarker, surface-antigen.
Shares HER2 IHC 3+ (HER2-positive by immunohistochemistry) and the tags biomarker, surface-antigen.
Shares PD-L1 CPS (combined positive score) and the tags biomarker, surface-antigen.