What is the usage and dosage of zotuximab? What medication guidelines should patients follow during treatment?

Zolbetuximab (Zolbetuximab) is a drug that targetsClaudin 18.2 (CLDN18.2) monoclonal antibody is mainly used to treat CLDN18.2 positive locally advanced or metastatic gastric cancer and gastroesophageal junction adenocarcinoma (GEJ carcinoma). It binds to the CLDN18.2 protein, triggering antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC), thereby inhibiting tumor growth. Rational use of this medicine and following relevant medication guidelines can help improve efficacy and reduce adverse reactions.

1. Usage and dosage

Zotuximab is usually used in combination with chemotherapy (such asmFOLFOX6 regimen) and is administered by intravenous infusion. Recommended dosage and usage are as follows:

Initial dose: 800 mg/m², intravenous infusion (IV infusion) on day 1. The infusion time takes about 2 hours.

Maintenance dose: 600 mg/m², intravenous infusion once every 2 weeks (Q2W) starting from day 8.

Pre-infusion preconditioning: To reduce infusion reactions, patients usually receive antihistamines (eg, diphenhydramine) and antipyretic analgesics (eg, acetaminophen) prior to infusion. If there is a history of nausea and vomiting, antiemetics (such as 5-HT3 receptor antagonists) can be used prophylactically.

The infusion rate and dose adjustment need to be adjusted according to the patient's tolerance. If serious adverse reactions occur, the infusion rate may need to be slowed down, the drug suspended or permanently discontinued.

2. Medication Guide and Precautions

1. Strictly screen patients to ensure indications

Zotuximab is only availableCLDN18.2Patients with positive gastric cancer or gastroesophageal junction adenocarcinoma. Therefore, immunohistochemistry (IHC) testing is required before treatment to confirm the expression of CLDN18.2. This drug is not recommended for patients who are CLDN18.2 negative.

2. Preventing and managing infusion-related reactions (IRR)

The drug may cause infusion-related reactions. Mild reactions include fever, chills, and rash. In severe cases, hypotension, bronchospasm, and even anaphylactic shock may occur. To reduce risk, it is recommended to:

During the first infusion, the patient should be closely monitored, the infusion time should be controlled to approximately 120 minutes, and necessary rescue measures should be prepared.

If mild to moderate IRR occursIRR, the infusion rate can be reduced or the drug can be stopped briefly, and antihistamines, glucocorticoids, etc. can be used to relieve symptoms.

If seriousIRR occurs (such as severe allergic reaction), the infusion should be stopped immediately and first aid treatment should be provided.

3. Monitoring for gastrointestinal adverse reactions

Common adverse reactions of zotuximab include nausea, vomiting, diarrhea, decreased appetite, etc. To relieve gastrointestinal discomfort, it is recommended to:

Use antiemetics (such as ondansetron) prophylactically to reduce nausea and vomiting.

Maintain adequate fluid intake to prevent dehydration.

If severe diarrhea or uncontrollable nausea and vomiting occurs, medication should be suspended and supportive treatment should be given.

4. Pay attention to electrolyte imbalance

Clinical trials have shown that zotuximab may cause electrolyte disorders such as hypokalemia, hypomagnesemia, and hyponatremia. It is recommended that patients regularly monitor blood potassium, blood magnesium, and blood sodium levels and supplement them as needed. If symptoms such as obvious fatigue, muscle weakness, and irregular heartbeat occur, you should seek medical treatment in time.

5. Long-term monitoring of liver function and blood indicators

This drug may affect liver function, and some patients may experience elevated levels of ALT and AST. It is recommended to check liver function regularly. If the transaminases increase more than 3 times the normal value, the dose needs to be suspended or adjusted. In addition, because combined chemotherapy may inhibit bone marrow hematopoiesis, patients need to regularly monitor routine blood tests, including white blood cell, platelet, and red blood cell counts.

6.Avoid pregnancy and breastfeeding

Zotuximab may be harmful to the fetus. Women of childbearing potential should use effective contraceptive measures during treatment and for at least4 months after the last dose.

Because this drug may be excreted in breast milk, lactating women should avoid breastfeeding during treatment and for at least 4 months after the last dose.

3. Things that patients need to cooperate with during treatment

Seek medical treatment on time and monitor regularly: Patients should receive treatment strictly according to the doctor's arrangements, and have regular checks on tumor progression, hematology and biochemical indicators.

Pay attention to physical changes: If you experience any discomfort, such as severe nausea, vomiting, diarrhea, dizziness, chest tightness, etc., you should report to your doctor immediately to adjust the treatment plan.

Eat a reasonable diet and enhance physical strength: Eat more foods rich in protein and vitamins and avoid irritating foods to maintain nutritional status and improve tolerance.

Pay attention to infection prevention: combined chemotherapy may lead to a decrease in immunity. Patients should pay attention to personal hygiene, avoid contact with sources of infection, and get vaccinated (such as influenza vaccine) when necessary.

VYLOY (zotuximab) is a monoclonal antibody against CLDN18.2 positive gastric cancer and gastroesophageal junction adenocarcinoma. During the treatment process, it needs to be used in strict accordance with the recommended dosage and infusion regimen, and the corresponding medication guidelines should be followed to reduce adverse reactions and improve efficacy. Patients should regularly monitor blood, liver and kidney function, and electrolyte levels, and be alert for infusion-related reactions, gastrointestinal discomfort, and potential electrolyte imbalances. At the same time, women of childbearing age need to take contraceptive measures to ensure the safety of treatment. Properly managing side effects, maintaining good living habits, and working closely with doctors can help increase the success rate of treatment and improve quality of life.

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