Cancer's Math That Doesn't Add Up

Colon cancer chemotherapy not improved by adding cetuximab or bevacizumab

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Combining existing drug therapies has long been an area of interest for cancer researchers. If one therapy works well, could adding another drug work even better?

Just such a study involving advanced colon cancer found that additions don't always add up to better results.

Following surgery, the standard chemotherapy regimen for Stage III colon cancer involves Leucovorin, fluorouracil, and oxaliplatin, or what's commonly called FOLFOX for short. Adding another drug - Erbitux (cetuximab} - did not extend life.

"Make sure you know exactly which drugs work for you."

The research, led by Steven R Alberts, MD MPH, professor of oncology at the Mayo College of Medicine, was published April 4, 2012 in JAMA. The clinical trial looked at the impact of adding cetuximab to a modified version of the FOLFOX regimen (mFOLFOX6).

The trial, conducted at institutions around the country, enrolled 2686 patients with Stage III colon cancer who had previously had surgery.

Participants were randomly assigned to receive  22 bi-weekly cycles of mFOLFOX6 with and without cetuximab, a drug that's used to treat colorectal cancer.

Dr. Alberts told dailyRx in an email that another similar study was conducted looking at the benefits of adding Avastin (bevacizumab) to the FOLFOX regimen. This study had been published October 12, 2010 in the Journal of Clinical Oncology.

"In both of these clinical trials we tried to improve upon the benefits obtained from FOLFOX by adding a targeted agent," Dr. Alberts said. "We believed that adding these drugs would be of benefit based on the results of trials for metastatic colon cancer showing benefit."

In the study he headed, after 28 months of follow-up, there was no benefit to adding cetuximab. Patients who were still disease-free and alive after three years follow-up was 28 (0-68) months included 74.6 percent on mFOLFOX6 alone and 71.5 percent for those who had mFOLFOX6 plus cetuximab.

Dr. Alberts said the other study involving bevacizumab had similar results.

"This is important as it means that patients with resected stage 3 colon cancer should only receive FOLFOX. It also means that what works in metastatic colon cancer will not necessarily work in resected stage 3 colon cancer, a paradigm that we have used for many years," said Dr. Alberts, who is also medical director of Mayo Clinic Cancer Center Clinical Research Office.

"This will create some challenges in how best to design the next generation of adjuvant trials for colon cancer," he added.

The cetuximab study was conducted as a collaborative trial of the North Central Cancer Treatment Group (NCCTG), this research was supported by grants from the National Cancer Institute, Department of Health and Human Services. Bristol-Myers Squibb, ImClone, sanofiaventis, and Pfizer provided unrestricted support to NCCTG.

A number of the authors disclosed financial relationships with pharmaceutical companies and other private and public entities.

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Review Date: 
May 2, 2012
Last Updated:
May 8, 2012