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Oncologists Respond Rapidly to Clinical Trial Evidence on Use of EGFR Inhibitors

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Key Points

  • Use of panitumumab and cetuximab in patients with metastatic colorectal cancer decreased significantly after the presentation of new clinical data, subsequent ASCO guidelines, and an FDA label change
  • These results suggest that the oncology community responds rapidly to new evidence and professional guidelines and readily incorporate predictive biomarkers into clinical practice.

Use of panitumumab (Vectibix) and cetuximab (Erbitux) in patients with metastatic colorectal cancer decreased significantly after the publication of clinical trial evidence that anti-EGFR antibodies should be restricted to wild-type KRAS tumors, subsequent ASCO guidelines recommending testing for KRAS mutations before initiating anti-EGFR treatment, and a U.S. Food and Drug Administration label change. Data showing the decrease in anti-EGFR treatment for patients with metastatic colorectal cancer “suggest that oncologists respond rapidly to new evidence and professional guidelines, and readily incorporate predictive biomarkers into clinical practice,” according to a study published in the Journal of Oncology Practice.

Study Details

A total of 5,089 patients commercially insured patients who received second-line therapy for metastatic colorectal cancer between 2004 and 2010 were identified using the LifeLink Health Plan Claims Database. “We reviewed claims between the years 2004 and 2010 in order to include the relevant events that resulted in recommendations to change use of anti-EGFR antibodies,” explained Efrat Dotan, MD, and colleagues from Fox Chase Cancer Center in Philadelphia, and University Hospitals Seidman Cancer Center and Case Comprehensive Cancer Center in Cleveland.

The researchers compared rates of treatment with anti-EGFR agents at four time points. At the first time point, June 2008, coinciding with the ASCO presentation of clinical trial evidence, 59.4% of patients had received an anti-EGFR antibody. That percentage decreased to 46.2% (P = .019) by February 2009, when ASCO published a provisional clinical opinion recommending KRAS testing.

On July 17, the FDA changed the labels for cetuximab (Erbitux) and panitumumab (Vectibix) to add that the two agents were not recommended for treating colorectal cancer with KRAS mutations in codon 12 or 13. By August 2009, the percentage of patients identified in the study as having received an anti-EGFR antibody had declined to 35.2% (P < .001). Eight months after the FDA label change, the percentage had further decreased to 16.2% (P < .001).

“Multivariable logistic regression did not show any affect of age, sex, comorbidities, or region of the country on this pattern,” the investigators stated.

Rapid Incorporation of Recommendations in Practice

“These results suggest the attentiveness of the oncologic community to clinical presentations at national meetings and ASCO guidance, with rapid incorporation of the recommendations into clinical practice. Furthermore, these results indicate that oncologists are receptive to the adoption of biomarkers that will enhance their ability to deliver effective therapy. It is also evident that oncologists change their practice promptly in the face of highly publicized data, even years after a drug’s original approval,” the investigators noted. The researchers stated that the study also “highlights the importance of rapid disclosure and communication of new clinical trial results that are relevant to standard practice.”

Citing a recent study estimating that KRAS testing in patients with metastatic colorectal cancer could save more than $400 million per year in the United States, the investigators added that compliance with the new recommendations “can result in significant cost savings by reducing the use of these drugs in patients who will not benefit.”

Efrat Dotan, MD, of Fox Chase Cancer Center, is the corresponding author for the Journal of Oncology Practice article.

The study was supported by grants from the National Cancer Institute and the American Cancer Society. For full disclosures of the study authors, visit jop.ascopubs.org.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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