Vaccine Therapy For Solid Tumors
For years researchers have tried to stimulate the immune system to fight cancer. Currently the FDA has approved several vaccines that I would like to review in this article.
Sipulecel (Provenge) is one of the first FDA approved vaccines for solid tumors it targets metastatic prostate cancer castrate resistant. Provenge activates the T cells of the immune system which in turn attack the prostate cancer cells by targeting the PAP prostatic acid phosphate antigen. It is effective in patients that are asymptomatic or minimally symptomatic from their disease. Provenge has been shown to prolong median survival beyond two years. The most common side effects from Provenge are flu like symptoms including fever, chills, fatigue, joint aches, and headaches. The most important side effect is an acute infusion reaction which can happen in 3% of individuals.
Ipilimumab (Yervoy) was FDA approved in 2011 for metastatic melanoma. Ipilimumab is a humanized antibody that recruits and activates T cells to attack the melanoma. Ipilimumab confers survival benefit in advanced melanoma. The most common side effects are rash, diarrhea, itching, and fatigue. More serious less frequent side effects include colitis, perforation, hepatitis, and inflammation of hormone glands.
Immonomodulatory agents have not been very successful so far in breast cancer. Currently additional strategies mixing vaccines with chemotherapeutic agents are being tested especially in triple negative breast cancers.
As far as lung cancer there are currently four Phase III clinical trials testing vaccines against specific antigens, which means Phase I and II trials have given promising results. This vaccine targets specific antigens present on lung cancer cells that generate an immune response with cytotoxic effects. Immunotherapy directed against non small cell lung cancer and small cell lung cancer will be combined with current therapies in order to improve overall survival.
Thus far it appears that the optimal use of vaccines in solid tumors occurs when the amount of disease is limited and asymptomatic or minimally symptomatic and can be used as monotherapy or combined with chemotherapy. It is clear that with increased knowledge of the biology of cancers that our therapeutic options have broadened tremendously over the last decade and hopefully will continue to do so.