Zolbetuximab
Zolbetuximab (Vyloy) is an intravenous cancer medicine used with chemotherapy as first-line treatment for certain advanced stomach and gastroesophageal junction cancers.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
How we combine label and product data →
Patient information guide — a plain-language walkthrough of Zolbetuximab, written from its FDA label.
What Zolbetuximab is used for
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Zolbetuximab (Vyloy) is used for one type of advanced cancer.
- Vyloy, given with fluoropyrimidine- and platinum-containing chemotherapy, is a first-line treatment for adults with locally advanced unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma.
- The cancer must be HER2-negative and claudin 18.2 positive, confirmed by an FDA-approved test.
How Zolbetuximab works
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Zolbetuximab is an antibody that attaches to claudin 18.2, a protein found on some stomach and GEJ cancer cells. It then helps destroy those cells through two immune-based processes called antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity.
In mouse tumor models, using it with chemotherapy had more antitumor activity than either one alone.
Zolbetuximab dosage
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Vyloy is given by IV infusion in a healthcare setting, together with chemotherapy. It is never given as an IV push.
- The first dose is larger. After that, it is given every 3 weeks or every 2 weeks.
- Treatment continues until the cancer progresses or side effects are unacceptable.
- Anti-nausea medicines are given before each infusion.
- Infusions start slowly and speed up if tolerated.
Your care team sets the exact dose and schedule.
Dosing details from the FDA-approved label
From the Zolbetuximab prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Locally advanced unresectable or metastatic HER2-negative gastric or GEJ adenocarcinoma whose tumors are CLDN18.2 positive, in combination with fluoropyrimidine- and platinum-containing chemotherapy (first dose)
- 800 mg/m2 intravenously
- Intravenous infusion only; initial infusion rate 100 mg/m2/hr for first 30-60 minutes, then 200-265 mg/m2/hr; premedicate with antiemetics prior to each infusion
- Locally advanced unresectable or metastatic HER2-negative gastric or GEJ adenocarcinoma whose tumors are CLDN18.2 positive, in combination with fluoropyrimidine- and platinum-containing chemotherapy (subsequent doses, every 3 weeks schedule)
- 600 mg/m2 intravenously every 3 weeks
- Continue until disease progression or unacceptable toxicity
- Initial infusion rate 75 mg/m2/hr for first 30-60 minutes, then 150-265 mg/m2/hr; no dose reduction recommended
- Locally advanced unresectable or metastatic HER2-negative gastric or GEJ adenocarcinoma whose tumors are CLDN18.2 positive, in combination with fluoropyrimidine- and platinum-containing chemotherapy (subsequent doses, every 2 weeks schedule)
- 400 mg/m2 intravenously every 2 weeks
- Continue until disease progression or unacceptable toxicity
- Initial infusion rate 50 mg/m2/hr for first 30-60 minutes, then 100-200 mg/m2/hr; no dose reduction recommended
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION • Administer by intravenous infusion only . Do not administer VYLOY as an intravenous push or bolus. ( 2.6 ) • The recommended first dose of VYLOY is 800 mg/m 2 followed by 600 mg/m 2 every 3 weeks or 400 mg/m 2 every 2 weeks. ( 2.3 ) 2.1 Patient Selection Select adult patients with locally advanced unresectable or metastatic HER2-negative gastric or GEJ adenocarcinoma whose tumors are CLDN18.2 positive (defined as ≥75% of tumor cells demonstrating moderate to strong membranous CLDN18 immunohistochemical staining) for treatment with VYLOY in combination with fluoropyrimidine- and platinum-containing chemotherapy using an FDA-approved test [see Clinical Studies ( 14 )]. Information on FDA-approved tests for the detection of CLDN18.2 is available at https://www.fda.gov/CompanionDiagnostics . 2.2 Prior to Administration If a patient is experiencing nausea and/or vomiting prior to administration of VYLOY, the symptoms should be resolved to Grade ≤1 before administering the first infusion. Premedication Prior to each infusion of VYLOY, premedicate patients with a combination of antiemetics (e.g., NK-1 receptor blockers and/or 5-HT3 receptor blockers, as well as other drugs as indicated) for the prevention of nausea and vomiting [see Warnings and Precautions ( 5.2 )]. 2.3 Recommended Dosage Administer VYLOY in combination with fluoropyrimidine- and platinum-containing chemotherapy as follows: • First dose: 800 mg/m 2 intravenously. • Subsequent doses: o 600 mg/m 2 intravenously every 3 weeks, or o 400 mg/m 2 intravenously every 2 weeks. • Continue treatment until disease progression or unacceptable toxicity. 2.4 Dosage Modifications for Adverse Reactions No dose reduction for VYLOY is recommended. Adverse reactions for VYLOY are managed by reducing the infusion rate, interruption of the infusion, withholding the dose, and/or permanently discontinuing VYLOY as described in Table 1 . Table 1. Recommended Dose Modifications for VYLOY for Adverse Reactions Adverse Reaction Severity Toxicity was graded per National Cancer Institute Common Terminology Criteria for Adverse Events Version 5.0 (NCI-CTCAE v5.0). Dose Modification Hypersensitivity or Infusion-related reactions [see Warnings and Precautions ( 5.1 )]. Grade 2 • Interrupt the infusion until Grade ≤1, then resume at a reduced infusion rate for the remaining infusion.
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Zolbetuximab side effects
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Common side effects
- Nausea
- Vomiting
- Tiredness (fatigue)
- Decreased appetite
- Diarrhea
- Numbness or tingling in hands and feet (peripheral sensory neuropathy)
- Abdominal pain
- Constipation
When to get medical help
- Tell your care team right away during or after an infusion if you have hives, repeated coughing, wheezing, throat tightness or a change in your voice. These can be signs of a serious allergic reaction (anaphylaxis).
- Report fever, chills, chest discomfort, back pain, cough or high blood pressure during an infusion, which can signal an infusion-related reaction.
- Tell your care team if nausea or vomiting is severe or won’t settle. It can lead to pausing or stopping treatment.
- Report any signs of serious infection, bleeding or breathing trouble, since serious and fatal events occurred in clinical studies.
The most common side effects with Vyloy plus chemotherapy are:
- Nausea and vomiting
- Tiredness
- Decreased appetite
- Diarrhea
- Numbness or tingling in hands and feet
- Abdominal pain
- Constipation
- Weight loss
- Allergic-type (hypersensitivity) reactions
- Fever
Blood tests may also show lower white blood cell, platelet and hemoglobin levels. Seek help right away for signs of anaphylaxis, severe infusion reactions or severe, ongoing vomiting.
Zolbetuximab warnings and precautions
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- Hypersensitivity and infusion-related reactions: serious and fatal reactions, including anaphylaxis, have occurred. You are monitored during and for at least 2 hours after the infusion. Watch for hives, repeated cough, wheeze, throat tightness, voice change, fever, chills, chest discomfort and back pain.
- Severe nausea and vomiting: very common, especially in the first cycle. It can lead to dose interruption or stopping treatment.
- Serious and fatal reactions, including infections, bleeding and breathing problems, occurred in clinical studies when used with chemotherapy.
Zolbetuximab interactions
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The label focuses on how Vyloy is used with other treatments.
- Chemotherapy (fluoropyrimidine- and platinum-containing): Vyloy is given first when both are given on the same day.
- Anti-nausea medicines: given before each infusion to reduce nausea and vomiting.
- Antihistamines: given before later infusions after a hypersensitivity reaction.
- Other IV drugs: should not be given through the same infusion line.
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Zolbetuximab
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- Your tumor must be HER2-negative and claudin 18.2 positive by an FDA-approved test.
- No contraindications are listed.
- Nausea or vomiting before the first infusion should settle first.
- Pregnancy: no human data. Use only if the benefit outweighs the potential risk.
- Do not breastfeed during treatment and for 8 months after the last dose.
- Not established in children.
- Older adults: no overall differences in safety or effectiveness were seen.
- Effects of severe kidney impairment and moderate to severe liver impairment are unknown.
What Zolbetuximab does in the body
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Zolbetuximab depletes cells that carry claudin 18.2. The relationship between drug levels and both benefit and side effects has not been fully characterized at the recommended doses.
How your body processes Zolbetuximab
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Zolbetuximab is given by IV infusion over about 2 hours. It is expected to be broken down into small peptides and amino acids. Its half-life is about 41 days on average, and steady state is reached by about 18 weeks. Age, sex and race had no clinically important effect on how the body clears it.
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Zolbetuximab: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Zolbetuximab — the kind of thing our pharmacy team would talk through with you at the counter.
What is Vyloy for?
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How will I receive it?
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What side effects should I expect?
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When should I tell the nurse right away?
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Can I take it if I’m pregnant or breastfeeding?
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Is Zolbetuximab available over the counter?
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When was Zolbetuximab first available?
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Who makes Zolbetuximab?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Zolbetuximab on HelloPharmacist
Zolbetuximab forms and strengths (how it comes)
Zolbetuximab is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Injection
How this form is used
- Vyloy is used with fluoropyrimidine- and platinum-containing chemotherapy as first-line treatment of HER2-negative, claudin 18.2-positive locally advanced unresectable or metastatic gastric or GEJ adenocarcinoma in adults.
- Vyloy is given by intravenous infusion only, never as an IV push or bolus.
- Vyloy infusions start slowly for 30 to 60 minutes, and the rate may then be increased if tolerated.
- Vyloy is given before chemotherapy when both are given on the same day.
- Anti-nausea medicine is given before each Vyloy infusion.
Zolbetuximab on the U.S. market: products, makers and brands
How Zolbetuximab appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
3 companies list 7 Zolbetuximab product records with the FDA, mostly as injection; the earliest marketing or approval year on record is 2024. Brand names on the directory include Vyloy; the rest are generics.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
How widely Zolbetuximab is used (Medicaid data)
A general measure of how commonly Zolbetuximab is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q2–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Zolbetuximab is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Zolbetuximab prescribed? Of the 1,600 medications we measure, Zolbetuximab ranks #1,396 by Medicaid prescriptions — more than 13% of them.
Utilization by Zolbetuximab product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
zolbetuximab-clzb 300 MG Injection Most dispensed
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2710430
zolbetuximab-clzb 100 MG Injection
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2695876
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Zolbetuximab, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 2 of 2 listed Zolbetuximab NDCs with Medicaid activity.
Compare Zolbetuximab products
A representative set of FDA-listed product records for Zolbetuximab — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Injection | ||||
| 20 mg/mL | Intravenous | Astellas Pharma US, Inc. × 4 listings | BLA | View NDC → |
| 100 mg/20 mL | — | Bamboo US Bidco LCC | DRUG FOR FURTHER PROCESSING | View NDC → |
| 300 mg/60 mL | — | Bamboo US Bidco LCC | DRUG FOR FURTHER PROCESSING | View NDC → |
| 20 mg/mL | — | Patheon Biologics LLC | DRUG FOR FURTHER PROCESSING | View NDC → |
Showing 7 of 7 products — FDA National Drug Code Directory. See every product, package size and price: browse all 7 Zolbetuximab NDCs →
Zolbetuximab side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Zolbetuximab — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Zolbetuximab in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Zolbetuximab FDA approval history
How Zolbetuximab went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Zolbetuximab recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 2695869 1 dose form · 2 strengths
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Dose form (SCDF) Injection RxCUI 2695873In current FDA listings
Look up RxCUI 2695869 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Zolbetuximab supply and shortage status
Whether Zolbetuximab is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
Zolbetuximab brand names
Zolbetuximab is sold under one brand name in the FDA directory — Vyloy. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Zolbetuximab: manufacturers and labelers
3 companies list Zolbetuximab products with the FDA. By number of product records, the largest are Astellas Pharma US, Inc., Bamboo US Bidco LCC, Patheon Biologics LLC. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Zolbetuximab drug class (RxNorm)
Zolbetuximab belongs to the Claudin 18.2-directed Cytolytic Antibody class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Zolbetuximab page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Astellas Pharma US, Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →