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Vectibix (panitumumab)
Starting Vectibix can bring up a lot of questions, for you and for the people who love you. Here you'll find what to expect, how to feel your best day to day and where to get help, so you can focus on your life and time together.
ℹ️ General information to help you and your loved ones talk with your care team, not medical advice. Read our disclaimer.
Targeted antibody (EGFR inhibitor) · Used for: Colorectal cancer
Types and tests it may fit: KRAS G12C colorectal cancer (RAS-mutant), RAS wild-type colorectal cancer (KRAS/NRAS normal)
💉 Given by IV or injection · Targeted antibody (EGFR inhibitor)
The quick guide
What it is: Targeted antibody (EGFR inhibitor).
How it's given: An IV infusion in a clinic about every 2 weeks.
How it works: Vectibix blocks EGFR on colorectal cancer cells. It's only for tumors that are RAS wild-type (normal KRAS and NRAS). It's also paired with Lumakras for KRAS G12C.
Side effects you may notice, and what helps at home
| Side effect | What can help |
|---|---|
| Dermatitis (skin rash and skin changes) (Rash, dry or itchy skin, nail-fold infections) | Thick fragrance-free moisturizer, sunscreen, gentle soap. |
| Fatigue (extreme tiredness) | Short walks and planned rest. |
| Diarrhea (loose, watery stools) | Fluids, bland food; ask your team about anti-diarrhea medicine early. |
| Low magnesium | Tell your care team; they can help. |
| Mucositis (mouth sores) | Soft toothbrush and salt-and-baking-soda rinses. |
Not everyone gets these. Your team may suggest other ways to manage them.
Call your care team now if you have:
- ⚠️ Boxed warning (FDA's most serious): Skin reactions are very common and can be severe. Call your team about bad rash, infection or peeling.
- Severe skin reactions, blisters or signs of skin infection
- Eye pain, redness or vision changes
- New cough or shortness of breath
Call 911 for trouble breathing, chest pain or signs of stroke.
🗓 What to expect
1️⃣ Before you start
- Ask your team for a written schedule and an after-hours phone number.
- Bring a list of all your medicines and supplements.
2️⃣ During each infusion
- You'll get the medicine through an IV in a clinic; nurses check you during the infusion.
- Tell the nurse right away about chills, itching, flushing, or trouble breathing.
- Bring a snack, water and something to pass the time.
3️⃣ Between doses
- Watch for the side effects below and use the checklist.
- Keep up with blood tests and visits.
- Call your team for anything in the red box.
✅ Side-effect checklist
Print this and check off what you notice so you can tell your team.
| Side effect | Noticed? | Notes for my team |
|---|---|---|
| Dermatitis (skin rash and skin changes) | ☐ | |
| Fatigue (extreme tiredness) | ☐ | |
| Diarrhea (loose, watery stools) | ☐ | |
| Low magnesium | ☐ | |
| Mucositis (mouth sores) | ☐ |
Help paying for Vectibix (panitumumab)
Vectibix (panitumumab) is made by Amgen.
Official manufacturer program:
- Amgen SupportPlus: Copay programs for commercial insurance and help finding other support.
Copay cards are usually only for people with commercial (job or marketplace) insurance. If you have Medicare or Medicaid, look at free-drug programs and these independent foundations:
- PAN Foundation: Copay grants for insured people, including those on Medicare, who meet income limits, when a fund for their diagnosis is open.
- FundFinder (from PAN): A free tool that tracks when copay foundation funds open and can send you an alert, so you don't have to keep checking each site.
- HealthWell Foundation: Grants for copays, deductibles, and premiums for insured people under income limits; the disease funds page shows which are open.
- CancerCare Co-Payment Assistance Foundation: Help with treatment copays for insured people with certain cancers who meet income limits.
- Patient Advocate Foundation Co-Pay Relief (TotalAssist): Copay and coinsurance help for insured patients who qualify by income, from the Patient Advocate Foundation.
- Good Days: Copay help, and in some funds travel costs, for insured people with chronic or life-changing illnesses who meet income limits.
- Accessia Health (formerly Patient Services, Inc.): Help with premiums, copays, and travel for people with certain chronic and rare conditions.
- The Assistance Fund: Copay, premium, and other cost help for insured people with serious illnesses, when a disease fund is open.
- NORD Patient Assistance Programs: Cost help for people with certain rare diseases, including some rare cancers.
- NeedyMeds: A free, open-to-anyone database of drug-maker programs, foundations, and low-cost clinics, plus a drug discount card.
Funds open and close often. FundFinder shows which are open now. See more help on paying for cancer treatment.
📋 Medicare: Medicare Part B usually covers drugs given by infusion in a doctor's office or hospital outpatient clinic. You typically pay 20% after the Part B deductible. See Medicare and your cancer drugs.
More: Help from drug makers · Our guide to paying for cancer treatment.
❓ Questions you and your loved ones can ask
- What is the goal of this treatment for me?
- How will we know if it's working?
- Which side effects should I call about right away, and what number do I call after hours?
- Which medicines, vitamins or supplements should I avoid?
- Will this affect my ability to work, drive or care for my family?
- What will this cost me, and who can help me with coverage?
Support for you and your family
- Fight Colorectal Cancer: Patient guides, advocacy and community
- Colorectal Cancer Alliance: Helpline (877-422-2030) and patient navigation
- CancerCare: Free counseling, support groups and financial help
- Cancer Support Community: Support groups, a helpline and the MyLifeLine online community
Questions people often ask
How does Vectibix work?
Vectibix blocks EGFR on colorectal cancer cells.
How is Vectibix given?
An IV infusion in a clinic about every 2 weeks.
How is Vectibix (panitumumab) given?
An IV infusion in a clinic about every 2 weeks.
How does Vectibix (panitumumab) work?
Vectibix blocks EGFR on colorectal cancer cells. It's only for tumors that are RAS wild-type (normal KRAS and NRAS). It's also paired with Lumakras for KRAS G12C.
What side effects are common with Vectibix (panitumumab)?
Side effects people often notice include Dermatitis (skin rash and skin changes), Fatigue (extreme tiredness), Diarrhea (loose, watery stools), Low magnesium, and Mucositis (mouth sores). Not everyone gets them, and our table above shares tips that may help at home.
When should I call my care team while on Vectibix (panitumumab)?
Call right away if you notice any of these: ⚠️ Boxed warning (FDA's most serious): Skin reactions are very common and can be severe. Call your team about bad rash, infection or peeling; severe skin reactions, blisters or signs of skin infection; eye pain, redness or vision changes. If you're ever unsure, it's always OK to call.
What cancers is Vectibix (panitumumab) used for?
On this site, we cover Vectibix (panitumumab) for colorectal cancer. Your care team decides whether it fits your situation.
📄 The official FDA label for Vectibix (panitumumab), including its patient information section, is on DailyMed.
Written by the Cancer Side Effects Guide team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write
Sources
Last updated: October 15, 2026. We summarize these sources in our own words.