Possible New Therapy Against Colon Cancer

Colorectal cancer patients had better results on combined medications than on a single commonly used medication

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

(RxWiki News) Some colon cancers can be harder to fight than others. New therapies are being investigated in the hopes of yielding better results for patients with these aggressive colon cancers.

Treating colon cancer with a combination of cancer-fighting medications, rather than a single medication, shrank more tumors in a small number of patients in a clinical trial.

Aiming to confirm that this new treatment will benefit a larger group of patients, the researchers are scheduled to begin a second phase of this clinical trial.

"Ask your doctor about the most effective cancer treatments."

David Hong, MD, of the University of Texas MD Anderson Cancer Center, was this study’s lead author.

Dr. Hong and his research team, which included scientists from drug-maker Genentech, set out to determine if using a combination of cancer medications would yield better results in a certain group of colorectal cancer patients with a mutation in the gene that produces the B-Raf (BRAF) protein. About 5 to 10 percent of colon cancer patients have that BRAF mutation, which makes their form of this disease especially aggressive and harder to treat than other colon cancers.

For this investigation, these researchers set out to determine the medical effects of treating patients with higher and higher doses of a combination of the following three medications: vemurafenib (Zelboraf), cetuximab (Erbitux) and irinotecan (Camptosar). Vemurafenib typically has been used alone to treat colon cancer, but it only shrinks about 10 percent of tumors, the researchers wrote.

As of January 2014, 10 patients were given those medication combinations. Seven of the 10 patients received the same doses of those medications. Three of the 10 also received all three medications but a higher dose of vemurafenib than that given to the seven other study participants.

Four of the five patients whose tumors had spread experienced a 44 percent shrinkage of those tumors, the researchers found.

These researchers had evaluated scans of patients’ tumors roughly every three weeks to check for possible shrinkage.

"What's promising is the fact that we're seeing these high response rates in early studies which suggests this could become a new standard of care down the line," Dr. Hong said in a press statement. "There's clearly some kind of synergistic activity with the combination."

The press annoucement about this research reported that two patients were added to the study, bringing the total number of participants to 12 and bringing to five the number of patients getting the higher dose of vemurafenib. That change resulted in eight of the nine patients on the combination of medications experiencing a 50 percent shrinkage of their tumors, the researchers concluded.

dailyRx requested documentation of that updated data but, as of this article's publication, has not received it.

The next phase of this clinical trial is slated to begin in summer 2014. The MD Anderson Cancer Center’s Scott Kopetz, MD, PhD, who worked on the first phase of this clinical trial, will lead the next phase of this investigation.

The results of this preliminary study were presented in Chicago on May 31 at American Society of Clinical Oncology's annual meeting.

Study funders were not reported.

Three of the study's 10 researchers reported that they have been awarded research grants from pharmaceutical makers Genentech and its parents company, Roche.

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Review Date: 
June 2, 2014
Last Updated:
June 2, 2014