WEDNESDAY, April 6, 2011 (HealthDay News) -- By giving more intensive chemotherapy along with drugs designed to boost the body's own immune system, researchers were able to roughly double survival time for patients with advanced, metastatic colorectal cancer compared to patients receiving standard chemotherapy alone.
In fact, the trial, results of which are being presented at the annual meeting of the American Association for Cancer Research in Orlando, was stopped early because of the promising findings.
"With this study, we have produced for the first time strong proof-of-concept that chemo-immunotherapy may be active and more efficacious than standard [chemotherapy] in metastatic colon cancer patients," said study lead author Dr. Pierpaolo Correale, an oncologist with Siena University School of Medicine in Siena, Italy.
The standard of care right now for patients with colorectal cancer that's spread to other regions is to use one of two dual-drug combinations of chemotherapy alone, or use them alongside a newly developed monoclonal antibody treatment such as Avastin (bevacizumab) or Erbitux (cetuximab). These approaches can boost overall survival to about 20 to 22 months.
For this study, the research team randomized 130 patients to receive either chemotherapy alone (with a regimen known as FOLFOX) or to receive FOLFOX plus drugs to ramp up the immune system (this regimen is known as GOLFIG).
The chemo/immune boost approach involves first giving patients gemcitabine plus standard FOLFOX chemotherapy (oxaliplatin, levofolinic acid and 5-FU/GOLF) that targets and kills the cancer cells in a number of ways -- all the while sending off signals alerting the immune system to the cancer.
This is then followed up with the administration of signaling molecules called cytokines that spur key immune cells into action. Another immune-boosting cancer drug, called aldesleukine, is also given to help boost the population of immune cells targeted against tumor cells.
At the time of data collection, the patients treated with this approach have survived an average 16.5 months without a relapse, compared with just 7.5 months in the chemo-only group.
But the study began in 2005, before the advent of drugs like Avastin or Erbitux, meaning that investigators do not yet know if GOLFIG would outperform regimens that include those medications. This needs to be looked at, said Correale.
On the other hand, many patients do not see a benefit from biological agents such as Erbitux or Avastin because they have the wrong genetic profile, noted one outside expert.
"Essentially, we have a very problematic subset of patients with metastatic colorectal cancer which are limited to two lines of chemotherapy and [perhaps] one biological agent," said Dr. Igor Astsaturov, assistant professor of medical oncology at the Fox Chase Cancer Center in Philadelphia.
"For those patients, which are about one-third of the overall patient population, this [new finding] will be particularly welcome news," Astsaturov said, while adding the caution that the results are still preliminary.
However, clinical use of the protocol may be delayed further by the fact that "there is no direct commercial interest of pharmaceutical companies," noted Correale, who is nevertheless planning larger trials.
The costs associated with GOLFIG, he added, are "four-to-five times lower than that produced by the current use of Avastin or Erbitux with apparently similar therapeutic results."
Because this study was presented at a medical meeting, the findings should be viewed as preliminary until they are published in a peer-reviewed journal.
There's more on colorectal cancer at the U.S. National Cancer Institute.