Astellas Pharma Inc. (TYO: 4503) announced that its VENTANA CLDN18 (43-14A) Assay has received approval from China’s National Medical Products Administration (NMPA), becoming the first and currently only companion diagnostic (CDx) reagent in China to identify patients eligible for VYLOY (zolbetuximab) treatment. The immunohistochemistry (IHC) assay, approved alongside VYLOY’s December 2024 NMPA authorization, enables precision patient selection for CLDN18.2-positive, HER2-negative gastric or gastroesophageal junction (GEJ) adenocarcinoma—a biomarker-defined population representing ~30-40% of advanced gastric cancer patients.
>400,000 new cases annually; world’s highest incidence; precision medicine adoption accelerating
CLDN18.2 Competition
VYLOY first-to-market in China (Dec 2024); competing with CAR-T (IMC002, satricabtagene) and ADCs in development; VENTANA assay creates barrier to entry
Companion Diagnostic Moat
First and only approved CDx establishes testing infrastructure lock-in; hospital laboratory standardization favors VENTANA platform
VENTANA CLDN18 approved in US, EU, Japan; China approval completes major market coverage; harmonized testing standards
Commercial & Reimbursement Implications
Phase
Activity
Timeline
Current
NMPA approval; hospital laboratory onboarding
Q1 2026
Testing Scale-Up
Pathology laboratory IHC platform installation; technician training
2026
VYLOY Commercialization
Biomarker-driven prescribing; NRDL negotiation for drug + test
2026-2027
Patient Access
CLDN18.2 screening integration into gastric cancer workup
2026+
Forward‑Looking Statements This brief contains forward‑looking statements regarding VENTANA CLDN18 assay adoption in Chinese hospital laboratories, VYLOY commercial performance, and CLDN18.2 testing market expansion. Actual results may differ due to pathology infrastructure variability, competitive CDx development, and VYLOY pricing/reimbursement negotiations.-Fineline Info & Tech
By Fineline Cube 