A Cancer Therapy Nearing Breakthrough

An approach to treating cancer known as monoclonal antibody therapy, that has already effectively proven itself, is on the threshold of becoming yet more powerful, according to an overview of recent research.

“We believe that antibody therapy has the capacity to immunize people against cancer,” said Louis Weiner, director of the Lombardi Comprehensive Cancer Center at Georgetown University Medical Center. “Treatment modifications might be able to prolong, amplify and shape a continuous immune response to cancer cells.”

Weiner, an internationally recognized expert in development and use of monoclonal antibodies, and two other scientists were chosen by editors of the journal The Lancet to write the overview of the last eight years of research in this area. Antibodies are proteins formed by cells of the body’s immune system that bind to and neutralize foreign chemicals and other matter, such as viruses and bacteria. Monoclonal antibodies are those that are all exactly the same and are pinpoint-targeted to a single threat, because they are produced from clones of one cell formed from the union of an immune-system B-cell and a tumor cell.

The Weiner overview said the therapies using monoclonal antibodies are today on the verge of a breakthrough.

“Scientists have been able to use new tools to measure effectiveness of these therapies, and have found that antibodies are capable of stimulating the immune system in ways that had not been appreciated to date, and which we can now take advantage of,” he said. The antibodies, he said, not only attach to cancer cells and stymie their function, but marshal the body’s immune system to attack the malignancy.

Monoclonal antibodies are already used to treat many cancers, including breast cancer (Herceptin and Avastin), colorectal cancer (Erbitux and Avastin), lung cancer (Avastin) and blood cancers (Rituxan and Campath).

“We believe that Herceptin and Rituxan, as examples, work in part by immunizing people against cancer, but at this point, the magnitude of that response is variable and is frequently very small,” Weiner said.

In the near future, however, scientists will engineer monoclonal antibodies that will produce a powerful immune response, he predicted, both in terms of a short-term killing of cancer cells and an inducement of a long-term “memory” response that alerts the immune system to any recurrence of the cancer.

“We have long thought that monoclonal antibodies are capable of stimulating the innate immune system, but we now have evidence that the therapy can prime an adaptive response as well,” Weiner said. “Such responses would make the treatment much more powerful, capable of keeping cancer under control.”