Class Name(s):

• 10:00 Antineoplastic Agents

Brand Name(s):

• Vyloy^®

WHY is this medicine prescribed?

Zolbetuximab-clzb injection is used in combination with other medications to treat certain types of gastric adenocarinoma (stomach cancer) or gastroesophageal junction adenocarcinoma (cancer where the esophagus and stomach meet). Zolbetuximab is in a class of medications called monoclonal antibodies. It works by stopping tumor-producing cells.

HOW should this medicine be used?

Zolbetuximab-clzb injection comes as a powder to be mixed with a liquid to be given intravenously (into the vein) by a healthcare provider at a hospital or clinic. It is usually given every 2 to 3 weeks. Your doctor will determine how frequently you should receive it and for how long you should receive it.

Your doctor will give you other medications prior to receiving zolbetuximab-clzb to help make sure you tolerate it. It is important to let your doctor know how you are feeling while receiving zolbetuximab-clzb therapy as your dose may need to be adjusted based on side effects.

Are there OTHER USES for this medication?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before receiving zolbetuximab-clzb,

• tell your doctor and pharmacist if you are allergic to zolbetuximab-clzb, any other medications, or any of the ingredients in zolbetuximab-clzb injection. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while receiving zolbetuximab-clzb, call your doctor. You should not breastfeed during treatment with zolbetuximab-clzb or for 8 months after your last dose.
• do not have any vaccinations without talking to your doctor.
• you should know that zolbetuximab-clzb has caused severe nausea and vomiting that sometimes causes your doctor to have to stop your treatment. Let your doctor know if you experience nausea and vomiting and if it continues to worsen.

What SPECIAL DIETARY instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What SIDE EFFECTS can this medicine cause?

Zolbetuximab-clzb may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• nausea and/or vomiting
• decreased appetite
• weight loss
• tiredness
• diarrhea
• tingling or numbness in arms or legs
• stomach pain
• constipation
• fever

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

• hives, rash or swelling of face, throat, lips; difficulty breathing or shortness of breath; chills or shaking; tiredness
• signs and symptoms of an infection such as fever, cough, nasal congestion, difficulty or painful urination, chills

Zolbetuximab-clzb may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to zolbetuximab-clzb.

Ask your pharmacist any questions you have about zolbetuximab-clbz.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™ Copyright, 2026. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: November 15, 2024.