A 2011 Nobel Prize in Physiology and Medicine is certainly impressive. Using a novel cancer treatment on yourself is both impressive and courageous. Dr. Ralph Steinman believed so enthusiastically in the cancer vaccines which he helped to develop that he used many of them to treat his own pancreatic cancer. Surviving for five additional years, Steinman was able to use his position on the Scientific Advisory Board of Celldex Therapeutics, Inc. (NASDAQ:CLDX) to guide the company into a new frontier of cancer immunotherapy.
Are cancer and the flu the same?
Clearly not – but the body’s immune response is similar. The flu vaccine works by exploiting the body’s natural immune response to prime the body for action by introducing an antigen, or chemical signature, from the virus that sticks to receptors on immune cells. The cells discovered by Steinman, called antigen presenting cells or APCs, internalize this antigen and flip it back outward to activate T-cells that destroy the invading pathogen. Merck & Co., Inc. (NYSE:MRK)‘s HPV vaccine, Gardasil, works to prevent cervical cancer by preventing viral infection. And work well it has, bringing in $1.6 billion in 2012.
Vaccines don’t always have to be preventative, though. Rather, they can be used to give the immune system a boost to fight a preexisting disease. For example, exposing patients to mutated forms of human proteins, like those arising during cancer, can trick the body into fighting its own cancer cells. A fellow Fool explained how Dendreon Corporation (NASDAQ:DNDN) used this approach with its prostate cancer vaccine, Provenge. Provenge treatment involves isolating a patient’s own APCs, exposing them to a prostate cancer antigen in the laboratory, and then reintroducing the ‘activated’ cells back into the patient.
A new technology for a new era of immunotherapy
Celldex Therapeutics, Inc. (NASDAQ:CLDX) has flipped Dendreon Corporation (NASDAQ:DNDN)’s biological model on its head. With a goal of specifically and efficiently targeting a subset of immune cells in vivo, Celldex Therapeutics, Inc. (NASDAQ:CLDX) designed antibodies that bind to the internalization receptor (the DEC-205 receptor) on APCs, and are also tethered to the cancer antigen. The APC internalizes the antibody/antigen complex, and can then signal to T-cells to begin the assault on cancerous tissue. This method has the benefits of classical vaccines, as well as the specificity and efficiency of Dendreon Corporation (NASDAQ:DNDN)’s Provenge, with a fraction of the cost.
Rindopepimut is Celldex Therapeutics, Inc. (NASDAQ:CLDX)’ leading drug candidate in Phase 3 trials for the treatment of front-line glioblastoma and Phase 2 trials for recurrent glioblastoma, but in theory it could treat many forms of cancer. In Phase 2 trials, rindopepimut improved 3 year survival to 23%-33% from 6-18% in historical controls. After 5 years, 15% of treated patients are still alive, compared to an expected 0% survival rate.