Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Colorectal Cancer Health Center

Font Size

Rectal Cancer Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Stage IV and Recurrent Rectal Cancer


Importantly, patients with mutant KRAS tumors may experience worse outcome when cetuximab is added to multiagent chemotherapy regimens containing bevacizumab. In a randomized trial, patients with metastatic colorectal cancer received capecitabine/oxaliplatin/bevacizumab with or without cetuximab. The median PFS was 9.4 months in the group receiving cetuximab and 10.7 months in the group not receiving cetuximab (P = .01). In a subset analysis, cetuximab-treated patients with tumors bearing a mutated KRAS gene had significantly decreased PFS compared with cetuximab-treated patients with wild type KRAS tumors (8.1 mo. vs. 10.5 mo.; P = .04). Cetuximab-treated patients with mutated KRAS tumors had a significantly shorter PFS compared with patients with mutated KRAS tumors not receiving cetuximab (8.1 mo. vs. 12.5 mo.; P = .003) as well as OS (17.2 months vs. 24.9 months; P = .03).[59][Level of evidence: 1iiDiii]

Panitumumab is a fully humanized antibody against the EGFR. In a phase III trial that has not yet been reported, patients with chemotherapy-refractory colorectal cancer were randomly assigned to panitumumab or best supportive care. Patients receiving panitumumab experienced improved OS. Despite the preliminary nature of this study, the FDA approved panitumumab for use in patients with metastatic colorectal cancer refractory to chemotherapy.[60]

In the Panitumumab Randomized Trial in Combination With Chemotherapy for Metastatic Colorectal Cancer to Determine Efficacy (PRIME [NCT00364013]) study, 1,183 patients were randomly assigned to FOLFOX4 with or without panitumumab as first-line therapy for metastatic colorectal cancer.[61] The study was amended to enlarge the sample size to address patients with the KRAS wild-type tumors and patients with mutant KRAS tumors separately. For patients with KRAS wild-type tumors, a statistically significant improvement in PFS was observed in those who received panitumumab-FOLFOX4 compared with those who received only FOLFOX4 (HR, 0.80; 95% CI, 0.66-0.97; P = .02, stratified log-rank test).[61][Level of evidence: 1iiDiii] Median PFS was 9.6 months (95% CI, 9.2 months-11.1 months) for patients who received panitumumab-FOLFOX4 and 8.0 months (95% CI, 7.5 months-9.3 months) for patients who received FOLFOX4. OS was not significantly different between the groups (HR, 0.83; 95% CI, 0.67-1.02; P = .072). For patients with mutant KRAS tumors, there was worse PFS with the addition of panitumumab (HR, 1.29; 95% CI, 1.04-1.62; P = .02, stratified log-rank test). Median PFS was 7.3 months (95% CI, 6.3 months-8.0 months) for panitumumab-FOLFOX4 and 8.8 months (95% CI, 7.7 months-9.4 months) for FOLFOX4 alone.

Next Article:

Today on WebMD

Colorectal cancer cells
The right diagnosis is the most important factor.
man with a doctor
Our health check will steer you in the right direction.
sauteed cherry tomatoes
Fight cancer one plate at a time.
bladder cancer x-ray
Do you know the warning signs?
Colon vs Rectal Cancer
New Colorectal Treatments
can lack of sleep affect your immune system
Cancer Facts Quiz
Virtual Colonoscopy
Picture of the Colon
Vitamin D