FDA approves zolbetuximab for CLDN18.2-positive gastric and gastroesophageal junction cancer

High-Certainty EvidenceFDA-approved for the exact stated cancer/useNot addressed

The FDA approved zolbetuximab-clzb (Vyloy), a claudin 18.2 (CLDN18.2)-directed cytolytic antibody, in combination with fluoropyrimidine- and platinum-containing chemotherapy, as a first-line treatment for adults with locally advanced unresectable or metastatic HER2-negative gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors are CLDN18.2-positive. The approval was based on two randomized, double-blind, phase 3 trials: SPOTLIGHT (ClinicalTrials.gov NCT03504397; primary publication in The Lancet, DOI 10.1016/S0140-6736(23)00620-7, PMID 37068504) and GLOW (ClinicalTrials.gov NCT03653507). Both trials met their primary endpoint of progression-free survival, as well as the key secondary endpoint of overall survival, when zolbetuximab was added to chemotherapy compared with chemotherapy alone. The FDA simultaneously approved a companion diagnostic test (the VENTANA CLDN18 RxDx Assay) to identify CLDN18.2-positive patients eligible for this treatment.

What This Means

In two separate, randomized, double-blind, phase 3 trials (SPOTLIGHT and GLOW), adding zolbetuximab to first-line chemotherapy significantly extended both progression-free survival and overall survival, compared with chemotherapy alone, in patients with CLDN18.2-positive, HER2-negative advanced gastric/GEJ cancer — meeting both the primary and a key secondary endpoint in each trial, a real, high evidentiary bar.

What This Doesn't Mean

This treatment requires a positive CLDN18.2 companion-diagnostic test result — it is not appropriate or approved for CLDN18.2-negative or HER2-positive gastric/GEJ cancer. This record's stated sample size and population reflect the SPOTLIGHT trial specifically; the GLOW trial's own separate population and results were not independently detailed.

Why It Matters

Gastric and gastroesophageal-junction cancer has historically had limited targeted-therapy options; a biomarker-selected therapy meeting overall survival in two independent confirmatory phase 3 trials represents a genuine, high-confidence advance for the roughly one-third to one-half of these cancers that test CLDN18.2-positive.

Promise & Proof

Proof — strength of the evidence 5 / 5

Base score from evidence stage: High-Certainty Evidence.
FDA-approved for the exact stated cancer/use.

Promise — potential significance if later evidence holds up 3 / 5

Baseline — a validly-evidenced story starts here; every further point below is an explicit, checkable reason.
The record includes substantive editorial reasoning about why this discovery matters.
A distinct follow-on/confirmatory study or trial is already cited as a secondary source — the field is already building on this finding.

These two ratings are automatically computed from this story's own structured evidence fields and are shown separately on purpose — they are never combined into one score. They describe this record, not a medical recommendation: they do not establish medical certainty, do not substitute for reading the cited sources, and are recalculated whenever the underlying evidence changes.

Population / Applicability

Studied in: Adults with locally advanced unresectable or metastatic HER2-negative gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors are CLDN18.2-positive, previously untreated, randomized to zolbetuximab plus chemotherapy or placebo plus chemotherapy (SPOTLIGHT trial population; a second, similarly-designed trial, GLOW, also supported this approval). (Adults)

Requires CLDN18.2 companion-diagnostic testing (the FDA-approved VENTANA CLDN18 RxDx Assay) before use — not appropriate for patients who have not been tested or who test negative. This record has not independently reviewed the full safety/tolerability profile, which should be added before publication.

Full evidence details

Study design: Randomized controlled trial
Sample size: 565

Funding & Conflicts

Sponsor/developer: Astellas Pharma Inc. — not independently confirmed against a primary corporate-disclosure document.

Regulatory status by jurisdiction

United States (FDA)

Status: FDA-approved for the exact stated cancer/use
Indication: First-line treatment, in combination with fluoropyrimidine- and platinum-containing chemotherapy, of adults with locally advanced unresectable or metastatic HER2-negative gastric or gastroesophageal junction adenocarcinoma whose tumors are CLDN18.2-positive.
Biomarker requirement: CLDN18.2-positive by an FDA-approved companion diagnostic; HER2-negative
Decision date: 2024-10-18
Source: Regulator record (opens in a new tab)

Guideline positions

Guideline

Position: Not addressed
Last verified: 2026-08-13

Primary evidence supporting this story

SPOTLIGHT trial primary results: zolbetuximab plus mFOLFOX6 in CLDN18.2-positive gastric/GEJ adenocarcinoma (The Lancet) (opens in a new tab) (Peer-reviewed paper) [Peer-reviewed] 10.1016/S0140-6736(23)00620-7 Load-bearing source DOI 10.1016/S0140-6736(23)00620-7, PMID 37068504
SPOTLIGHT trial primary results: zolbetuximab plus mFOLFOX6 in CLDN18.2-positive gastric/GEJ adenocarcinoma (The Lancet). DOI 10.1016/S0140-6736(23)00620-7, PMID 37068504.

Additional context

SPOTLIGHT trial registry (opens in a new tab) (Clinical-trial registry) NCT03504397 NCT03504397
SPOTLIGHT trial registry. NCT03504397.

Why Should I Trust This?

1 source at Tier 2 — Peer-reviewed primary research, trial registries, regulatory documents, official conference abstracts
Last reviewed: 2026-08-13

This panel summarizes real, checkable facts about this record's own sources and review status — it is not a trust score, and reading it is not a substitute for reading the cited sources yourself.

Discovery Timeline

Every recorded change to this record's content or publication status, in order.

2026-08-13 Status change — Status changed from "Legacy / Unverified" to "In editorial review".
2026-08-13 Status change — Status changed from "In editorial review" to "Verified".

Last reviewed 2026-08-13