panitumumab (Rx)

Brand and Other Names:Vectibix

Dosing & Uses


Dosage Forms & Strengths

injectable solution

  • 100mg/5mL

Metastatic Colorectal Cancer Wild-Type RAS


  • Indicated for both KRAS and NRAS as determined by an FDA-approved test for this use (eg, next-generation sequencing [NGS] kit)
  • Combination therapy: With FOLFOX, as first-line treatment
  • Monotherapy: Following disease progression after prior treatment with fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy


  • 6 mg/kg IV infusion over 60 minutes (over 90 minutes if dose >1 g) q14Days  
  • Also see Administration

Dosage Modifications

Infusion reactions

  • Mild-moderate (grade 1-2): Reduce infusion rate by 50%
  • Severe (grade 3-4): Terminate infusion; permanently discontinue depending on severity and/or persistence

Dermatologic reactions

  • First occurrence of grade 3 dermatologic reaction: Withhold 1 to 2 doses; if reaction improves to
  • Second occurrence of grade 3 dermatologic reaction: Withhold 1 to 2 doses; if reaction improves to
  • Third occurrence of grade 3 dermatologic reaction: Withhold 1 to 2 doses; if reaction improves to
  • Fourth occurrence of grade 3 dermatologic reaction: Permanently discontinue
  • Grade 3 or 4 dermatologic reaction that does not recover to

Dosing Considerations

Limitation of use

  • Not indicated for the treatment of patients with RAS-mutant mCRC or for whom RAS mutation status is unknown
  • Prior to treatment initiation, assess RAS mutational status in colorectal tumors and confirm the absence of a RAS mutation

Safety and efficacy not established


Adverse Effects


Erythema (65%)

Acneiform dermatitis (57%)

Pruritus (57%)

Hypomagnesemia (39%)

Fatigue (26%)

Abdominal pain (25%)

Paronychia (25%)

Skin exfoliation (25%)

Nausea (23%)

Rash (22%)

Constipation (21%)

Diarrhea (21%)

Vomiting (21%)

Skin fissures (20%)

Cough (14%)

Dermatologic toxicity, Grade 3 and 4 (14% )

Acne (13%)

Peripheral edema (12%)


Abdominal pain, Grade 3 and 4 (7% )

Pulmonary embolism, Grades 3 to 5 (7% )

Hypomagnesemia, Grade 3 and 4 (4% )

Angioedema, All grades (3% to 4% )

Complication of infusion, All grades (3% to 4% )

Constipation, Grade 3 and 4 (3% )

Binding antibodies (0.4-3.8%)

Diarrhea, Grade 3 and 4 (2% )

Vomiting, Grade 3 and 4 (2% )

Nausea, Grade 3 and 4 (1% )

Anaphylaxis (1% )

Complication of infusion, Grade 3 and 4 (1% )

Sepsis (1%)


Pulmonary fibrosis

Frequency Not Defined


Growth of eyelashes

Increased tears

Ocular hyperemia



Postmarketing Reports

Skin and subcutaneous tissue disorders: Skin necrosis, angioedema

Immune system disorders: Anaphylactoid reaction

Eye disorders: Keratitis/ulcerative keratitis, corneal perforation

Life threatening and fatal bullous mucocutaneous disease



Black Box Warnings

Dermatologic toxicity

  • Dermatologic toxicities, some severe (NCI-CTC grade 3 or higher), related to panitumumab blockade of EGF binding and subsequent inhibition of EGFR-mediated signaling pathways have been reported in patients receiving panitumumab monotherapy
  • Dermatologic toxicities were reported in 90% of patients and were severe in 15% of patients receiving monotherapy




Increased tumor progression, increased mortality, or lack of benefit in patients with RAS-mutant mCRC; determine RAS-mutant tumor status in an experienced laboratory using an FDA-approved test before treatment

Monitor patients who develop dermatologic toxicities while receiving panitumumab for the development of inflammatory or infectious sequelae; limit sun exposure

Panitumumab is not indicated for use in combination with chemotherapy due to increase in mortality or toxicity

Permanently discontinue in patients developing pulmonary fibrosis/interstitial lung disease

Monitor electrolytes and institute appropriate treatment if needed

Terminate the infusion for severe infusion reactions

Ocular toxicities reported; monitor for keratitis, ulcerative keratitis, or corneal perforation; interrupt or discontinue for acute or worsening keratitis, ulcerative keratitis, or corneal perforation

Discontinue permanently if patient develops interstitial lung disease, pneumonitis, or lung infiltrates

Avoid pregnancy

Not indicated for treatment of patients with colorectal cancer that harbor somatic RAS mutations in exon 2 (codons 12 and 13), exon 3 (codons 59 and 61), and exon 4 (codons 117 and 146) of either KRAS or NRAS (RAS)

Progressively decreasing serum magnesium levels leading to severe (grade 3-4) hypomagnesemia reported; monitor patients for hypomagnesemia and hypocalcemia prior to initiating treatment, periodically during treatment, and for up to 8 weeks after completion of treatment; other electrolyte disturbances, including hypokalemia, have also been observed; replete magnesium and other electrolytes as appropriate

Dermatologic toxicity

  • Clinical manifestations reported include, dermatitis acneiform, pruritus, erythema, rash, skin exfoliation, paronychia, dry skin, and skin fissures
  • Severe dermatologic toxicities complicated by infection including sepsis, septic death, and abscesses requiring incisions and drainage
  • Whether these mucocutaneous adverse reactions were directly related to EGFR inhibition or to idiosyncratic immune-related effects (eg, Stevens Johnson syndrome or toxic epidermal necrolysis) is unclear
  • Withhold or discontinue panitumumab and monitor for inflammatory or infectious sequelae in patients with severe dermatologic toxicities

Pregnancy & Lactation


Based on data from animal studies and mechanism of action; therapy can cause fetal harm when administered to pregnant women; limited available data on use of therapy in pregnant women are not sufficient to inform a risk of adverse pregnancy-related outcomes; panitumumab is a human IgG monoclonal antibody and may be transferred across the placenta during pregnancy; advise pregnant women of the potential risk to the fetus


  • Females: Therapy can cause fetal harm when administered to a pregnant woman; advise females of reproductive potential to use effective contraception during treatment and for 2 months after last dose


  • Females: Based on results from animal fertility studies conducted in female cynomolgus monkeys, therapy may reduce fertility in females of reproductive potential; effects in animal studies were reversible.


There are no data on presence of drug in human milk or effects of panitumumab on breastfed infant or on milk production; human IgG is present in human milk, but published data suggest that breast milk antibodies do not enter neonatal and infant circulation in substantial amounts; because of potential for serious adverse reactions in breastfed infants from therapy, advise women not to breastfeed during treatment and for 2 months after final dose

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.



Mechanism of Action

Human monoclonal antibody to human EGF receptor


Peak Plasma Concentration: 213±59 mcg/mL

Trough Concentration: 39±14 mcg/mL

Half-Life, Elimination: 7.5 days

Clearance: 4.9±1.4 mL/kg/day


Colorectal cancer expressing with KRAS wild-type respond more favorably to regimens that include anti-EGFR antibodies (cetuximab, panitumumab); whereas, the presence of KRAS mutation (codon 12 or 13) showed an absence of biological and clinical activity for the anti-EGFR antibody treatment

Strongly recommended that patients with metastatic CRC who are being considered for treatment with anti-EGFR antibody therapy should be tested for the presence of a KRAS mutation prior to the administration of therapy (NCCN guidelines)

Genetic testing laboratories

  • The following companies are currently offering KRAS mutation status testing
  • Clarient, Inc. (
  • Caris Diagnostics (
  • DxS (
  • Genzyme Genetics (
  • LabCorp (
  • Response Genetics (


IV Preparation

Inspect vial; discard if discolored

Some particulate matter may be present, OK to use (will be removed by filter)

Withdraw dose amount & dilute to 100 mL with 0.9% NaCl (if dose >1 g, in 150 mL)

Mix by gentle inversion, do not shake

Final concentration not to exceed 10 mg/mL

Use diluted solution within 6 hr if stored at room temp, or within 24 hr if stored at 2-8°C

IV Administration

For IV infusion only; not for IV push or bolus

Use low-protein-binding 0.2-0.22 micron in-line filter

Flush IV line with 0.9% NaCl before and after administration

Use infusion pump

Doses &lge;1 g: Infuse over 60 min through peripheral line or indwelling catheter; ; if first infusion tolerated, administer subsequent infusion over 30-60 min

Doses >1 g: Infuse IV over 90 min


Unopened vials

  • Store vials in the original carton under refrigeration at 2-8°C (36-46°F) until time of use
  • Protect from direct sunlight
  • Do not freeze
  • Discard any unused solution remaining in the vial

Diluted solution

  • Room temperature: Administer within 6 hr of preparation
  • Refrigerated (2-8°C [36-46°]): Administer within 24 hr of preparation
  • Do not freeze


Vectibix intravenous
400 mg/20 mL (20 mg/mL) vial
Vectibix intravenous
100 mg/5 mL (20 mg/mL) vial

Copyright © 2010 First DataBank, Inc.


Patient Handout

Patient Education
panitumumab intravenous




WARNING: Panitumumab has caused very serious skin reactions, which can sometimes lead to serious infections. Tell your doctor right away if you develop any signs of a skin reaction, including acne, mild rash/itching, warmth/redness/swelling of the skin (including around the nails), dry/flaking skin, or skin sores (especially with pus). Get medical help right away if you develop any signs of a serious infection (such as sepsis), including fever, fast heartbeat, mental/mood changes (such as confusion), or signs of kidney problems (such as change in the amount of urine).

USES: This medication is used to treat a certain type of cancer of the colon (large intestine) or rectum. Panitumumab is a man-made protein (monoclonal antibody) that binds to a certain protein (epidermal growth factor receptor-EGFR). It works by slowing or stopping the growth of cancer cells.

HOW TO USE: This medication is given by injection into a vein by a health care professional. It is given as directed by your doctor, usually every 14 days. The dosage is based on your weight and response to treatment.

SIDE EFFECTS: See also Warning section.Diarrhea, nausea, vomiting, tiredness, constipation, abdominal pain, and growth of eyelashes may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: swelling ankles/feet, unusual weakness, irregular heartbeat, severe muscle spasms, mouth sores, signs of eye problems (such as eye redness/itching/irritation, watery eyes, vision changes), signs of lung disease (such as cough, shortness of breath), menstrual changes.Prolonged and/or severe diarrhea may lead to dehydration and electrolyte imbalance. Tell your doctor right away if you develop any of the following: extreme thirst, decreased urination, dizziness, fainting.Get medical help right away if you have any very serious side effects, including: seizures.Rarely, panitumumab has caused very serious infusion reactions, including an allergic reaction. Get medical help right away if you develop fever, chills, or symptoms of an allergic reaction.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before receiving panitumumab, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: lung disease (such as pulmonary fibrosis, interstitial pneumonitis), low magnesium/calcium blood levels.Sunlight may worsen any skin reactions that may occur while you are receiving this drug. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using panitumumab. Panitumumab may harm an unborn baby. Ask about reliable forms of birth control while using this medication and for 2 months after stopping treatment. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication.Based on information from related drugs, this medication may pass into breast milk. Breast-feeding is not recommended while using this medication and for 2 months after the end of treatment. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

NOTES: Lab and/or medical tests (such as magnesium/calcium levels) should be done before you start using this medication, while you are using it and for 8 weeks after completion of treatment. Keep all medical and lab appointments. Consult your doctor for more details.

MISSED DOSE: It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

STORAGE: Not applicable. This medication is given in a clinic and will not be stored at home.

Information last revised June 2023. Copyright(c) 2023 First Databank, Inc.

IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.



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The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

Tier Description
1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
NC NOT COVERED – Drugs that are not covered by the plan.
Code Definition
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Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
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Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
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Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
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