Uses

Panitumumab is an EGFR antagonist indicated for adult patients with wild-type RAS metastatic colorectal cancer (mCRC), either in combination with FOLFOX as first-line therapy or as monotherapy after prior fluoropyrimidine, oxaliplatin, and irinotecan-based chemotherapy. Also used with sotorasib for KRAS G12C-mutated mCRC.

Do not use if

No formal contraindications listed in the FDA label. However, panitumumab is not beneficial and may be harmful in patients with RAS-mutant mCRC; use in these patients is not recommended.

Side effects

Dermatologic toxicity is the most common adverse effect, occurring in approximately 90% of patients, and may be severe (Grade 3+) in 15%. Other adverse effects include hypomagnesemia, diarrhea, fatigue, nausea, and infusion-related reactions. Pulmonary toxicity is rare.

Warnings

Severe dermatologic toxicity may occur; monitor closely and consider dose modification or discontinuation. Hypomagnesemia and hypocalcemia occur frequently; monitor and replace electrolytes. Increased mortality and tumor progression observed in patients with RAS-mutant mCRC. Infusion reactions and pulmonary toxicity have been reported.

How it works

Panitumumab is a fully human IgG2 monoclonal antibody that binds with high affinity to the extracellular domain of EGFR, blocking ligand binding and downstream signaling through RAS/RAF/MAPK and PI3K/AKT pathways, thereby inhibiting tumor cell proliferation and survival.

Storage

Store vials refrigerated at 2°–8°C (36°–46°F) in the original carton. Protect from direct sunlight. Do not freeze or shake. Discard unused portion after opening.