Quick Facts About: Panitumumab

Vectibix

Yes, in 2006.

Wild-type RAS metastatic colorectal cancer

*All dosages indicated here are specific to colorectal cancer treatment.

Panitumumab is administered intravenously.

Dosage is dependent on drug combination in the treatment regimen and is based on the patient’s weight (milligram per kilogram, mg/kg).

Patients may be administered 6 mg/kg once every 2 weeks via an infusion pump over 60 minutes. If the initial infusion is tolerated, subsequent infusions may be administered over 30-60 minutes. Doses greater than 1000 mg should be infused over 90 minutes. Dosing may be adjusted, interrupted or discontinued depending on tolerability and individual safety.

The above dosing applies to use of panitumumab as part of the following treatment plans:

• In combination with FOLFOX (folinic acid + fluorouracil + oxaliplatin) as first line treatment
• In combination with FOLFIRI (folinic acid + fluorouracil + irinotecan) as treatment for patients who have received fluoropyrimidine-based chemotherapy (excluding irinotecan)
• As monotherapy in patients who failed treatment with fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy

Panitumumab is contraindicated in patients with the following conditions:

• History of severe or potentially fatal hypersensitivity to panitumumab
• Existing interstitial pneumonitis or pulmonary fibrosis
• Lactation
• Combination therapy with bevacizumab-containing chemotherapy

In addition, special precaution is required for patients with:

• History of interstitial pneumonitis, pulmonary fibrosis, keratitis or severe dry eye
• History or risk factors for ulcerative keratitis
• Ongoing pregnancy

Common side effects of panitumumab may include:

• Acne, dry skin, rash, itching
• Swelling or irritation around your fingernails or toenails
• Loss of appetite, nausea, diarrhea
• Blisters or ulcers in your mouth, red or swollen gums, trouble swallowing
• Tired feeling, weakness
• Low potassium

These common side effects may compound into more severe side effects, such as

• Allergic reactions
• Severe or persistent 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 levels leading to leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling
• Dehydration symptoms
• 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
• Skin problems

Panitumumab is a monoclonal antibody used in immunotherapy.

Panitumumab is a recombinant IgG₂ kappa monoclonal antibody that inhibits cell growth, proliferation and transformation. It binds with high affinity and specificity to human epidermal growth factor receptor (EGFR) on both normal and tumor cells.

When normal ligands such as EGF bind to EGFR, intracellular proteins that regulate gene transcription are activated, leading to cellular growth, survival, motility and proliferation. It also leads to activation of the wild-type KRAS gene, a known proto-oncogene. When panitumumab binds to EGFR, it inhibits receptor autophosphorylation but all other EGFR ligands, thereby exerting antineoplastic action.