Two American scientists, James P. Allison and Carl H. June, will today receive the Paul Ehrlich and Ludwig Darmstaedter Prize in the Paulskirche in Frankfurt. Both give the patient's own immune system the lasting ability to fight cancer, Allison against late stage melanoma, June against leukemia. The two scientists have made the mobilization of the body's own defenses a therapeutic option to which ever more people owe their survival. "In immunotherapy, it's not the tumor but the immune system that is targeted. This marks a new therapeutic principle in oncology," wrote the Scientific Council of the Paul Ehrlich Foundation, in explaining its decision. Allison is Professor at the University of Texas MD Anderson Cancer Center in Houston, while June is Professor at the Perelman School of Medicine at the University of Pennsylvania in Philadelphia. The Paul Ehrlich and Ludwig Darmstaedter Prize is among the most prestigious international awards granted in the Federal Republic of Germany in the field of medicine. The Prize will be presented by Professor Harald zur Hausen, Chairman of the Scientific Council.
Allison and June use T cells for immunotherapy. Allison targets what is now termed an "immune checkpoint". Normally, an immune response weakens quickly so as not to cause the body collateral damage. T cells have their own molecular brakes for this purpose. Allison investigated this braking effect and concluded that by blocking this effect he could bring about a longer and more sustained immune reaction to cancer. The blocking is achieved by means of a therapeutic antibody, which has been approved under the name Yervoy® (ipilimumab). In late stage melanoma, durable responses of at least ten years occur in about 22% of patients. In explaining checkpoint inhibition, Allison says: "We don't attack the tumor cells directly. We unleash the T cells to effectively attack many types of cancer in humans. That's the big difference to conventional chemotherapy."
Carl June uses the patient's own T cells as a therapeutic agent by combining their killer properties with the "tracking" attributes of an antibody. June takes blood from the patients, isolates the T cells and equips them with an antibody-like protein that leads the T cells directly to the cancer cells. The protein is known as CAR, and the treatment is therefore called CAR therapy. Until now June has treated mainly patients whose leukemia has been resistant to therapy. Some patients show no signs of the disease even years later. CAR therapy is still a niche treatment, but various drug companies are working on bringing it into broad clinical use. "The biggest challenge now is to use CARs against solid tumors, not only against leukemia," says June. One of his next targets is pancreatic cancer.
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