New products, updated recommendations, and exciting prospects for the future bring many changes to this area of practice
Today, it seems we may be making history again, this time with a record number of new vaccines in various stages of development for use as therapy against diseases that we've never even considered preventable or curable before-therapeutic areas such as cancer, HIV, Alzheimer's disease, herpes, and even multiple sclerosis (see table on page 26). No longer are vaccines used only for protection against infectious diseases. They are now used as new therapeutic approaches to fighting disease. The development of DNA vaccines, adjuvants, and vaccines administered transdermally might sound futuristic, but, in fact, these advances are just around the corner.
"Never before has so much been going on in the immunization world," said Mary S. Hayney, Pharm.D., BCPS, associate professor of pharmacy at the University of Wisconsin School of Pharmacy. "The rate of change in immunization recommendations is rapidly accelerating and several vaccines have been or are likely to be licensed in 2005 and 2006."
Hayney is right. Since the beginning of 2005, the ACIP has added four final and four provisional recommendations to the childhood immunization schedule, numerous vaccine products were approved by the Food & Drug Administration, and, according to market analyst group Frost & Sullivan, at least 14 vaccines are currently in phase III or are being reviewed by the FDA. Growth is expected not only in the United States but in Europe as well, where the market is expected to increase to $6.58 billion by 2012, up from $3.2 billion in 2005. Current data from the market research company Datamonitor show a trend toward increased use of adjuvants and multiple antigens in an attempt to strengthen the potency of vaccines against diseases such as HIV and cancer. Cancer currently accounts for about 60% of all vaccine pipeline products.
In layman's terms, therapeutic cancer vaccines do not prevent the disease but rather attempt to jumpstart and trick the immune system into identifying the malignant cells as foreign. The biggest problem with developing a cancer vaccine is that targeting against tumor-associated antigens often doesn't work because healthy cells possess the same antigens. Thus, an attack against the abnormal cells is never mounted, allowing continued growth of the cancer. Recently, however, researchers have identified methods to specifically target antigens found only on abnormal cells, leaving healthy cells healthy and giving cancer patients another reason to hope.