• Oncology Clinical Trials
• Gastrointestinal Cancers

• Oncology Clinical Trials
• Gastrointestinal Cancers

First-line treatment for metastatic colorectal cancer (mCRC) is combination chemotherapy (CT) plus a monoclonal antibody (mAB). The Cetuximab and/or Bevacizumab Combined With Combination Chemotherapy in Treating Patients With Metastatic Colorectal Cancer [CALGB/SWOG 80405; NCT00265850] study examined whether a strategy that blocked endothelial growth factor receptors with the mAB cetuximab (CET) or blocked vascular endothelial growth factors with the mAB bevacizumab (BEV) provided a greater improvement in the effectiveness of CT.

In the CALGB/SWOG 80405 study, patients with KRAS wild-type (codons 12 and 13) mCRC and ECOG performance status 0 to 1, at the discretion of the physician and patient at enrollment, received either irinotecan hydrochloride, fluorouracil, and leucovorin calcium (FOLFIRI CT) or modified leucovorin calcium, fluorouracil, and oxaliplatin (mFOLFOX6 CT) [Venook A et al. Ann Oncol. 2014 (abstr O-0019)]. The patients were randomized to CET (CT + CET arm; n = 578) or BEV (CT + BEV arm; n = 559).

The study started in November 2005, and 2 changes were made to the study design in June 2009: patients with unselected mCRC (ie, without KRAS wild-type tumors) were not eligible, and the third study arm with the combination of CET + BEV was eliminated.

The median follow-up was 24 months. The median age of the patients was 59 years, and 61% were men. Overall survival, the primary end point, was 29.04 months (range, 25.66 to 31.21) with CT + BEV, compared with 29.93 months (range, 27.56 to 31.21) with CT + CET (HR, 0.92; 95% CI, 0.78 to 1.09; p = .34).

Progression-free survival, as assessed by the investigator, was 10.84 months (range, 9.86 to 11.4) and 10.45 months (range, 9.66 to 11.33) in the CT + BEV and CT + CET arms, respectively. No evidence of disease after surgery was identified in 94 patients after a median follow-up of 40 months (range, 8.0 to 86.0). Study outcomes or serious toxicity did not differ in relation to the sex of the patient or the treatment that the patient received.

An analysis of the CT regimens in this study is underway, but it is limited because 73% of patients received mFOLFOX6 and only 27% received FOLFIRI. Other analyses are underway to identify subsets of patients who may have more benefit from a specific regimen compared with another.

In patients with KRAS wild-type mCRC, CT + CET or CT + BEV had the same effect on overall survival; thus, either regimen is appropriate for first-line therapy, according to Alan P. Venook, MD, University of California, San Francisco, San Francisco, California. The overall survival of > 29 months achieved in this study was greater than that seen in other studies in this population.

• © 2014 MD Conference Express®