Panitumumab: uses, dosing, side effects & brands

How panitumumab is dosed

From the FDA label for Vectibix (application BLA125147). Other panitumumab products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.

RAS Wild-Type mCRC: Administer 6 mg/kg every 14 days as an intravenous infusion over 60 minutes (≤ 1000 mg) or 90 minutes (> 1000 mg). ( 2 ) KRAS G12C -mutated mCRC: Administer 6 mg/kg every 14 days as an intravenous infusion over 60 minutes (≤ 1000 mg) or 90 minutes (> 1000 mg) in combination with sotorasib. ( 2 ) 2.1 Patient Selection RAS Wild-Type mCRC Prior to initiation of treatment with Vectibix as monotherapy, assess RAS mutational status in colorectal tumors and confirm the absence of a RAS mutation in exon 2 (codons 12 and 13), exon 3 (codons 59 and 61), and exon 4 (codons 117 and 146) of both KRAS and NRAS . KRAS G12C-mutated mCRC Prior to initiation of treatment with Vectibix in combination with sotorasib, confirm the presence of the KRAS G12C mutation using an FDA-approved test. Information on FDA-approved tests for the detection of RAS mutations in patients with mCRC is available at: http://www.fda.gov/CompanionDiagnostics. 2.2 Recommended Dosage RAS Wild-Type mCRC The recommended dosage of Vectibix is 6 mg/kg, administered as an intravenous infusion every 14 days until disease progression or unacceptable toxicity [see Dosage and Administration (2.4) ] . Appropriate medical resources for the treatment of severe infusion reactions should be available during Vectibix infusions [see Warnings and Precautions (5.4) ] . KRAS G12C -mutated mCRC Administer the first…

Panitumumab side effects

Who shouldn’t take panitumumab

Panitumumab and breastfeeding

From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.

No information is available on the clinical use of panitumumab during breastfeeding. Because panitumumab is a large protein molecule with a molecular weight of about 147,000 Da, the amount in milk is likely to be very low. It is also likely to be partially destroyed in the infant's gastrointestinal tract and absorption by the infant is probably minimal. Until more data become available, panitumumab should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. The manufacturer recommends that breastfeeding be discontinued during panitumumab therapy and for 2 months after the final dose.

National Institute of Child Health and Human Development, record revised November 15, 2023. LactMed states its information is not a substitute for professional judgement.

What people report to the FDA about panitumumab

The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 6,085 reports naming panitumumab, and the FDA flagged 98% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:

• diarrhoea842 reports
• neutropenia511 reports
• dermatitis acneiform496 reports
• rash436 reports
• nausea426 reports
• hypomagnesaemia347 reports
• stomatitis340 reports
• colorectal cancer metastatic335 reports

Source: openFDA drug/event (FAERS), retrieved July 25, 2026.

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