With all the fervor around Dendreon’s (DNDN) Provenge there is renewed interest in cancer vaccines, a therapeutic approach which deals with stimulating the body’s immune system to attack tumors. This approach is based on the notion that our immune system is capable of recognizing and responding to various types of tumors, once it recognizes them as such. It is presumed that cancer cells are constantly created in our body, but in most cases, our immune system manages to recognize these cells and get rid of them by using an impressive repertoire of mechanisms. Unfortunately, in some cases, those cancer cells manage to evade the surveillance of the immune system and begin to multiply in an uncontrolled manner, leading to the creation of tumors. Almost ten years after the approval of Rituximab, the first monoclonal antibody for cancer, it seems like the time is right for another flavor of cancer immunotherapy – cancer vaccines.
In recent years, there have been some great improvements in the field of cancer therapy thanks to early diagnosis and new forms of therapies, such as monoclonal antibodies and nanoparticle-coated compounds. For over two decades, cancer vaccines have demonstrated impressive results in early pre-clinical trials, which gave rise to great expectations within the scientific community. Unfortunately, scientists couldn’t replicate the early phase success into clinical trials, but there are finally some encouraging signs . With several promising candidates which are currently being evaluated in clinical trials, the cancer vaccine field might become the next big thing in cancer therapy.
An immune response is a complicated, dynamic and multi-phased process, which is orchestrated by a vast number of factors. Like many other biological processes, the immune response is certainly not easily manipulated. The ideal cancer immunotherapy should target cancer cells exclusively without attacking any normal cells in the body. The problem is that biological systems are so complex and sometimes even chaotic that it is virtually impossible to predict the specific kind of treatment that would yield the desirable effect. Unfortunately, drug development is still limited to the classic trial and error approach, which produces dozens and hundreds of ineffective potential treatments for every one that actually works. Bearing in mind that tumors are actually cells that, by definition, manage to evade the immune system ( they wouldn’t exist otherwise), manifesting an immune response directed at those cells is even more challenging. Cell Genesys (CEGE) might have found a formula for an effective, specific cancer vaccine with limited side effects – GVAX. Their approach can theoretically be applied to many kinds of cancer, though the most advanced results are with Hormone Refractory Prostate Cancer [HRPC].