new prostate cancer vaccine: is there anything immunology can’t do?

Holy crap!!! Whoever said immunology is useless? I’ve always been a little wary of cancer immunology because it is a field that is trying to harness the power of a system we still know almost nothing about. I view Cancer Biology as a high risk, high reward field. And it sounds like someone might finally be able to get some of that sweet sweet reward.

Dendreon Corp, a Seattle-based biotech recently released results were from a Phase III clinical trial that included 512 men with late-stage prostate cancer who had not benefited from drugs that lower testosterone (testosterone has a growth/survival effect on most prostate cancers so testosterone blocking agents can often greatly reduce a prostate cancer load).

The new drug by Dendreon Corp is called Provenge (or Sipuleucel-T) and word is that it might become the first therapeutic vaccine for any kind of cancer. Unlike a prophylactic vaccine, which we have all received as kids to prevent future infection by for example the polio virus, Provenge actually treats it’s target by stimulating the immune system to attack cells expressing certain cancer-specific proteins. Therapeutic vaccines are also being developed for other cancers where specific tumor antigens exist that can distinguish the tumor from non-cancerous “self”, for example cervical or head and neck cancers caused by HPV. Of course, the therapeutic benefit of these vaccines will be eliminated if tumors stop expressing those targetted proteins–which will eventually happen through a process of natural selection as long as the proteins are necessary for tumor survival.

To make Provenge, the patient must undergo leukapheresis, a procedure similar to dialysis, where their blood is taken and their own antigen presenting cells are extracted and incorporated into the vaccine. Provenge is then administered intravenously to the patient, with very few side effect–mostly a few days of flu-like symptoms–but nothing like chemotherapy or hormonal therapy side effects. And in case you are wondering, the current treatment for advanced prostate cancer is Taxotere, a chemotherapy drug with severe side effects, including neuropathy, hair loss, and vomiting.

Booyah! Immunology to save the day, as usual. Come on cancer biologists–let’s get with the program here! HAHAHAHAHAHAHAHA!!!!!! Just kidding, much love to the cancer biologists but this is pretty cool.