Review article: panitumumab--a fully human anti-EGFR monoclonal antibody for treatment of metastatic colorectal cancer.

BACKGROUND

Panitumumab is a fully human monoclonal IgG2 antibody targeting the epidermal growth factor receptor (EGFR).

AIM

To review the efficacy of panitumumab in the treatment of metastatic colorectal cancer (mCRC).

METHODS

Available literature identified from PubMed and conference websites was reviewed.

RESULTS

In phase 2-3 studies, panitumumab monotherapy achieved objective response rates (ORRs) of 8-13% in relapsed/refractory EGFR-expressing mCRC. In a randomized phase 3 study (463 patients), panitumumab almost halved the risk of disease progression/death vs. a control group receiving only best supportive care (hazard ratio 0.54; 95% CI: 0.44-0.66; P < 0.0001). Objective response was achieved in 22/231 (10%) patients randomized to panitumumab--and also in 20/176 (11%) patients assigned to the control group who received panitumumab in a separate crossover protocol after disease progression. Response was confined to patients with tumours harbouring wild-type KRAS (ORR approximately equal to 20%). Panitumumab is also being evaluated in earlier lines of treatment. Panitumumab monotherapy is generally well tolerated; the most common toxicities are skin toxicity (approximately equal to 90%) and diarrhoea (<30%). Development of anti-panitumumab antibodies (0.3% by ELISA) and grade 3-4 infusion reactions (<1%) are rare.

CONCLUSION

Panitumumab is an effective monotherapy option for patients with relapsed/refractory EGFR-expressing mCRC harbouring wild-type KRAS.