EGFR inhibitor may provide convenient option for wild-type KRAS metastatic colorectal cancer

Data from a phase 3 trial comparing panitumumab (Vectibix) to cetuximab (Erbitux) for the treatment of wild-type KRAS metastatic colorectal cancer (mCRC) in patients who have not responded to chemotherapy, provide the oncology community with important information on the use of EGFR inhibitors for patients with mCRC.

Results from the ASPECCT (‘763) trial were presented at the European Cancer Congress, in Amsterdam. ASPECCT was designed to determine if panitumumab provided a comparable survival benefit to cetuximab for mCRC patients. Secondary end points included safety, patient-reported outcomes, progression-free survival, time to response, time-to-treatment failure, and duration of response.

The study enrolled 1,010 patients with wild-type KRAS mCRC, who had previously received irinotecan-, oxaliplatin-, and fluorouracil-based treatment for metastatic disease, but had no prior anti-EGFR regimens. The trial was designed and powered to demonstrate non-inferiority for overall survival (OS).

Patients were randomized 1:1 to receive panitumumab (6 mg/kg every 2 weeks) or cetuximab (400 mg/m² followed by 250 mg/m² weekly). Crossover between the arms was not allowed.

“The trial met its primary end point and showed that panitumumab retained 106% of the OS benefit of cetuximab over best supportive care in patients with wild-type KRAS mCRC,” David Chang, MD, vice president, Global Oncology Development at Amgen, told Formulary. “The ASPECCT study also provides an opportunity to explore other measures of clinical benefit, safety, and health economics between panitumumab that is administered once every 2 weeks, and cetuximab that is administered once every week.”

In the study, median OS for patients treated with panitumumab was 10.4 months, compared to 10.0 months for patients treated with cetuximab.

Adverse events included known events such as rash, low levels of magnesium in the blood, and infusion reactions.

In the United States, colorectal cancer is the second leading cause of cancer deaths.