Panitumumab

Panitumumab is a prescription medication used for the treatment of metastatic colorectal cancer. 

• Panitumumab is available under various brand names: Vectibix

Common side effects of Panitumumab include:

• skin reactions (redness, acne, itching, or rash)
• diarrhea
• nausea
• vomiting
• tiredness
• constipation
• stomach or abdominal pain, or
• growth of eyelashes

Serious side effects of Panitumumab include:

• severe or ongoing diarrhea;
• sudden chest pain or discomfort, wheezing, dry cough or hack, feeling short of breath;
• redness, swelling, or irritation of your eyes or eyelids, vision changes;
• swelling in your face;
• low potassium level--leg cramps, constipation, irregular heartbeats, fluttering in the chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling;
• dehydration symptoms--feeling very thirsty or hot, being unable to urinate, heavy sweating, or hot and dry skin;
• signs of a kidney problem--little or no urinating; painful or difficult urination; swelling in your feet or ankles; feeling tired or short of breath; or
• skin problems--severe or worsening acne, swelling or infection around your fingernails or toenails, skin itching, redness, dryness, peeling, cracking, or oozing.

Rare side effects of Panitumumab include:

• none

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult dosage

Injectable solution

• 100 mg/5mL

Metastatic Colorectal Cancer Wild-Type RAS

Adult dosage

• 6 mg/kg IV infusion over 60 minutes (over 90 minutes if dose above 1 g) every 14 Days

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Panitumumab has no noted severe interactions with any other drugs.
• Panitumumab has no noted serious interactions with any other drugs.
• Panitumumab has no noted moderate interactions with any other drugs.
• Panitumumab has no noted minor interactions with any other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

Contraindications

• None

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Panitumumab?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Panitumumab?”

Cautions

• 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 an 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 or ulcerative keratitis; interrupt or discontinue for acute or worsening keratitis
• Discontinue permanently if a patient develops interstitial lung disease, pneumonitis, or lung infiltrates
• Avoid pregnancy
  • Not indicated for the 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 the 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
• Contraception
  • 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 the last dose
  • Infertility
  • 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.
• Lactation
  • There are no data on the presence of the  drug in human milk or the effects of panitumumab on the 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 the final dose