Panitumumab (Vectibix, Amgen) is an anti-EGFR monoclonal antibody used for the treatment of metastatic CRC. The drug is administered via IV infusion. This section covers the common adverse reactions associated with panitumumab treatment as well as warnings, precautions, drug interactions and other contraindications.
Common adverse reactions
Warnings and precautions
Drug interactions and other contraindications
Panitumumab common adverse reactions
Patients receiving panitumumab monotherapy in clinical trials reported skin rash, paronychia (infection of the nailbed), fatigue, nausea and diarrhea; these reactions were reported by at least 20% of patients.
Patients receiving panitumumab in combination with FOLFOX chemotherapy reported diarrhea, stomatitis, mucosal inflammation, asthenia, paronychia, anorexia, hypomagnesemia, hypokalemia, rash, acneiform dermatitis, pruritus (itch) and dry skin.
Panitumumab warnings and precautions
Severe dermatologic reactions were reported in 15% of patients who received panitumumab in clinical trials; these reactions included acneiform dermatitis, paronychia and skin fissures resulting from dry and cracked skin. Patients with dermatologic reactions should be monitored closely for inflammation and infection, as this may lead to abscesses, sepsis, necrotizing infections and mucocutaneous reactions such as SJS and TEN. Panitumumab should be discontinued in cases of severe dermatologic or mucocutaneous reaction.
Patients should be monitored for hypomagnesemia and hypocalcemia before, during and for 8 weeks after panitumumab treatment.
Additional adverse events associated with panitumumab therapy include:
- infusion reactions;
- acute renal failure (when given in combination with systemic chemotherapy);
- pulmonary fibrosis/ILD;
- photosensitivity; and
- ocular toxicities, including keratitis and ulcerative keratitis.
Panitumumab drug interactions and other contraindications
An increase in mortality and toxicity was noted among patients in a clinical trial who were randomized to receive panitumumab in combination with bevacizumab and systemic chemotherapy. The increase in serious adverse events led to these patients receiving decreased doses of systemic chemotherapy compared with those receiving bevacizumab and chemotherapy.
Like cetuximab, panitumumab should only be used in patients with KRAS wild-type metastatic CRC; it is not indicated in patients with mutant RAS or in those with unknown RAS status.