How long does it usually take for Zotuximab/Veloximab to take effect?

Zolbetuximab (zolbetuximab)-VYLOY is a monoclonal antibody drug that targets CLDN18.2. Its clinical effect is not felt immediately like analgesics or antipyretics, but it takes a certain period of time to show anti-tumor activity. Usually, it takes several weeks to months after gastric cancer patients receive this drug in combination with chemotherapy before efficacy trends can be observed in imaging examinations or changes in tumor markers. The speed at which it works is related to multiple factors, including the size of the patient's tumor burden, genetic testing results, the body's immune function status, and combined treatment options.

Generally speaking, the action process of targeted antibody drugs is gradually revealed. During the initial 1 to 2 treatment cycles, doctors will closely monitor the patient's clinical response and adverse reactions to evaluate whether to continue the medication. In some patients, signs of tumor shrinkage may be observed at an early stage, but in most cases, the efficacy can only be confirmed through CT or MRI scans after 2 to 3 months of regular treatment. For some patients with more complex conditions, the efficacy may appear more slowly, but if standard treatment can be adhered to for a long time, the overall survival benefit will still have clinical significance.

Patients cannot judge the value of a drug by “immediate effect”. As an immune-related targeted therapy, the mechanism of action of zotuximab determines that the efficacy requires a cumulative process. Doctors usually comprehensively evaluate the efficacy based on RECIST criteria or clinical symptoms during treatment, rather than relying solely on short-term observation. For patients, regular follow-up visits and patient waiting are very important. At the same time, the drug combined with chemotherapy may increase some gastrointestinal side effects. Therefore, while waiting for the curative effect, good side effect management can also ensure the smooth progress of the treatment.

As more real-world data accumulate, the medical community will have a clearer understanding of the onset time and long-term benefits of zotuximab. Overall, most patients see positive efficacy trends within a few months of treatment, and consistent medication use is the key to achieving maximum benefit.

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