Is genetic testing necessary before zotuximab treatment? Can the testing costs be reimbursed?

Zolbetuximab (zolbetuximab-clzb)-VYLOY must undergo specific biomarker testing before treatment, rather than "gene testing" in the traditional sense. The drug is a targeted antibody whose main target is the tight junction protein claudin 18.2 (CLDN18.2). Therefore, before use, patients must evaluate CLDN18.2 expression in tumor tissue (gastric cancer) through immunohistochemistry (IHC). Patients were considered suitable for zotuximab treatment only if CLDN18.2 showed moderate to strong expression in at least 75% of tumor cells. This screening process is a critical prerequisite for determining treatment benefit, so testing is required.

Currently CLDN18.2 expression detection is gradually becoming popular in China, but its coverage in medical insurance still has regional differences. In some provinces and cities, biomarker testing projects based on clear treatment indications may be included in local medical insurance or outpatient special disease reimbursement, especially in oncology departments of large tertiary hospitals. Some commercial insurances also list this type of targeted pre-drug testing as a claim support item. However, for self-paying patients, the cost of CLDN18.2 testing is usually between 1,000 and 3,000 yuan, and the cost depends on hospital equipment, reagent brands and pathology services. Since this type of testing is still in the promotion stage, it is recommended that patients consult the pathology department or medical insurance office of their hospital in advance to understand whether it complies with the reimbursement policy and the required materials.

It is worth emphasizing that zotuximab is different from traditional chemotherapy drugs. Its targeting mechanism determines that the therapeutic effect is highly dependent on the specific expression of tumor surface proteins. Blind use of the drug may not only be ineffective, but may also increase the economic burden. Therefore, standardizing CLDN18.2 testing is a key step to ensure the accuracy of patient medication. In addition, this kind of detection belongs to the category of pathological immunostaining and does not involve high-throughput gene sequencing. Therefore, the detection cycle is relatively short, and a report can usually be issued within a few days, ensuring that treatment plans are formulated in a timely manner.

Reference materials:https://www.astellas.com/en/news/29401