Immune-boosting colorectal cancer drug shows promise

New data on an emerging treatment that aims to fight colorectal cancer by stimulating the immune system have been presented at the ESMO 15th World Congress on Gastrointestinal Cancer.

The findings confirm the biological action of the drug called MGN1703 and suggest it may be possible to identify which gastrointestinal cancer patients will benefit most from the treatment, reported Prof Hans-Joachim Schmoll from Martin Luther University, Halle, Germany.

MGN1703 is a small DNA molecule recognised by a receptor --called toll-like receptor 9-- that is expressed in certain immune system cells. The drug is designed to broadly activate all components of the innate immune system to stimulate the destruction of cancer cells.

The new data come from the final analysis of the phase II IMPACT study, which investigated MGN1703 in 59 patients with metastatic colorectal cancer.

The IMPACT study was an international, randomised, double-blind trial that was conducted in patients who had achieved disease control after 4.5 to 6 months of chemotherapy.

Standard chemotherapy for patients with metastatic colorectal cancer who respond to treatment is often completely or partially discontinued until the disease progresses. It was during this 'maintenance' phase of treatment that the new drug was administered.

Prof Schmoll and colleagues had intended to test the drug on 129 patients, but difficulties recruiting participants meant the trial was closed after 59 patients had been randomly assigned to either MGN1703 (43 patients) or placebo (16 patients).

"After a median follow-up of 17.3 months, MGN1703 prolonged profession-free survival from the start of induction as well as start of maintenance therapy, including four patients with sustained progression-free survival who are still on treatment," Prof Schmoll says.

Colorectal Cancer Facts The American Cancer Society estimates that in 2011 about 141,210 people will be diagnosed with colorectal cancer and about 49,380 people will die of the disease in the US. In both men and women, colorectal cancer is the third most commonly diagnosed cancer and the third leading cause of cancer death. The majority of these cancers and deaths could be prevented by applying existing knowledge about cancer prevention and by increasing the use of established screening tests. In the past decade, there has been unprecedented progress in reducing colorectal cancer incidence and death rates in most US population groups; this progress has come about largely through the prevention and early detection of colorectal cancer through screening. Even more progress is possible by increasing access to and utilization of colorectal cancer screening tests; currently, only about half of people aged 50 or older, for whom screening is recommended, report having received colorectal cancer testing consistent with current guidelines.