Zolbetuximab dosage standards and adjustment plans for different situations

Zolbetuximab (Zolbetuximab) is a monoclonal antibody targeting the Claudin 18.2 (CLDN18.2) protein. It is mainly used to treat advanced gastric cancer and gastroesophageal junction adenocarcinoma with positive CLDN18.2 expression. The drug kills tumor cells by inducing antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). According to the protocol recommended in clinical trials, the usual dosage for the first dose is 800 mg/m², followed by a maintenance dose of 600 mg/m² every three weeks, administered by intravenous infusion.

In clinical use, the dose of zotuximab can be accurately calculated based on the patient's body surface area (BSA). The first infusion time is usually controlled at about 120 minutes to reduce the risk of infusion-related reactions; if the patient tolerates it well, the subsequent infusion time can be appropriately shortened to 90 minutes. In addition, it is recommended to give antihistamines, antipyretic analgesics, or glucocorticoids as pretreatment before infusion to reduce the incidence of adverse reactions.

When patients experience adverse reactions or special clinical conditions, the regimen of zotuximab needs to be adjusted individually. For example, when grade ≥2 infusion-related reactions (such as fever, chills, hypotension) occur, the infusion should be suspended, and the administration should be continued at a slower rate after the symptoms are relieved. If severe gastrointestinal reactions or laboratory index abnormalities occur (such as ALT/AST elevation), it may be necessary to delay the next course of treatment or reduce the dose under the guidance of a doctor.

For the elderly, patients with hepatic and renal insufficiency, or patients with underlying diseases, extreme caution is required when using zotuximab. Although the available data do not suggest that dose adjustment is necessary, patients need to be closely monitored for tolerance and adverse events during treatment, and decisions should be made on a case-by-case basis whether to adjust the dose or extend the dosing interval. Reasonable dose management is of great significance to maximize drug efficacy and improve patients' quality of life.

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