Administration of cetuximab every 2 weeks in the treatment of metastatic colorectal cancer: an effective, more convenient alternative to weekly administration?

The primary purpose of this paper is to present the available evidence for the administration of cetuximab on an every-2-weeks basis in combination with irinotecan in metastatic colorectal cancer (mCRC). Cetuximab is an epidermal growth factor receptor-targeted IgG(1) monoclonal antibody that is approved for use in combination with irinotecan or as monotherapy in the treatment of mCRC. The currently approved dosing regimen for cetuximab is a 400-mg/m(2) initial dose followed by 250 mg/m(2) weekly. Many commonly used chemotherapy agents for mCRC (including irinotecan alone or in combination with 5-fluorouracil [5-FU]/folinic acid [FA] and oxaliplatin plus 5-FU/FA) are administered on an every-2-weeks basis. The ability to synchronize the administration of cetuximab and concomitant chemotherapy is desirable for both patients and health care workers. A cetuximab dose of 500 mg/m(2) every 2 weeks exhibited predictable pharmacokinetics, which were similar to those of the approved weekly dosing regimen. Active serum concentrations of cetuximab were maintained throughout the 2-week dosing period with this regimen. There was no difference between the dosing regimens on pharmacodynamic parameters in skin. The efficacy and safety of the every-2-weeks dosing regimen were similar to those reported for the approved weekly dosing regimen. The indication from these preliminary findings is that every-2-weeks administration of cetuximab (500 mg/m(2)) may be a potentially convenient alternative to the approved weekly dosing regimen of 250 mg/m(2) (following an initial dose of 400 mg/m(2)) in the treatment of mCRC.