Approved in 2006 as monotherapy for the treatment of patients with EGFR-expressing metastatic colorectal cancer (mCRC) after disease progression following treatment, panitumumab has been a mainstay metastatic disease for more than a decade. In 2014, it received additional indication as first-line therapy for the treatment of patients with EGFR-expressing mCRC in combination with FOLFOX, but in 2017, use was narrowed to wild-type RAS (not mutated RAS).
Category/Class
Monoclonal antibody, EGFR antagonist
Indication
Used in combination with FOLFOX for first-line treatment of wild-type RAS mCRC. Also used as monotherapy in wild-type RAS mCRC following progression after treatment with fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy. RAS mutation status must be evaluated prior because patients with RAS-mutant mCRC may experience increased tumor progression, greater risk of mortality, or lack of response with panitumumab.
Dosing
6 mg/kg every 14 days
Administration
Infuse over 60 (≤ 1,000 mg) or 90 minutes (> 1,000 mg). Use an infusion pump with a low-protein–binding 0.2 or 0.22 mcm inline filter. Flush IV line with 0.9% sodium chloride before and after. Administer preparations within six hours if kept at room temperature or within 24 hours if stored at 36°–46°F.
Adverse Reactions
Dermatologic reactions occur in 90% of patients, with severe reactions occurring in 15% of patients. With monotherapy, the most common nondermatologic reactions are fatigue, nausea, and diarrhea. In combination with FOLFOX, the most common nondermatologic reactions are diarrhea, stomatitis/mucosal inflammation, asthenia, anorexia, hypomagnesemia, and hypokalemia. Rare but serious events include infusion reactions (4%; e.g., fever, chills, dyspnea, bronchospasm, hypotension), interstitial lung disease and pulmonary fibrosis (1%), and ocular toxicities (15%).
Nursing Considerations
Before treatment begins, validate that patients have been tested for RAS-mutant mCRC.
Do not administer via IV push or as a bolus. It must be infused over at least 60 minutes.
Monitor for reactions during and after each infusion. Most infusion reactions occur within the first 30 minutes of the first or second infusion but can occur up to 24 hours later.
Mild to severe dermatologic and infusion reactions may require dose or rate reductions, dose delays, or discontinuation.
Monitor magnesium and calcium blood levels before, periodically during, and for up to eight weeks after treatment is complete.
Patients receiving panitumumab in combination with chemotherapy should be monitored for severe diarrhea.
Patient Education
Women of reproductive potential must use effective contraception during and at least two months after treatment. Panitumumab may decrease fertility in women but is usually reversible.
Women should not breastfeed during and for two months after treatment.
Counsel patients to contact their cancer care team as soon as possible if they experience any adverse reactions.
Teach patients to limit sun exposure because it can exacerbate dermatologic toxicities.
Encourage patients to maintain or increase fluid intake if they develop diarrhea to prevent dehydration and renal dysfunction.
Gero-Oncology Considerations
When administered as monotherapy, patients aged 65 years or older experienced the same levels of efficacy and safety as younger patients. However, when administered with FOLFOX, patients older than 65 experienced a higher incidence of severe diarrhea and other serious adverse events.
Safe Handling
Panitumumab is a hazardous drug because of its reproductive risk. Use safe handling procedures.
Patient Assistance
For more information, visit the Vectibix website.