PHILADELPHIA - After a vaccination or an infection, the human immune system remembers to keep protecting against invaders it has already encountered, with the aid of specialized B-cells and T-cells. Immunological memory has long been the subject of intense study, but the underlying cellular mechanisms regulating the generation and persistence of long-lived memory T cells remain largely undefined. Now, University of Pennsylvania School of Medicine researchers have found that a common anti-diabetic drug might enhance the effectiveness of vaccines.

    The Washington Post has recently commented on Howard I. Scher of the Memorial Sloan-Kettering Cancer Center and Maha Hussain of the University of Michigan being in fear for their safety after they raised opposition to Dendreon Corporation’s experimental vaccine Provenge and its approval by the FDA. An expert panel in March recommended the FDA approve Provenge but in May, Scher and Hussain, along with others, questioned the effectiveness of Provenge and asked for more evidence to support its effectiveness. This raised a debate among patients about the access to experimental treatments which the article covers. 

    Telomerase is an enzyme that allows a cell’s DNA to maintain its length after division. Without telomerase, cells can only divide a certain amount of times before their DNA is shortened leading to cellular death. This limit of division in normal cells is known as the hayflick limit. A detailed definition of the hayflick limit can be found here.

    Telomerase is not active in normal dividing somatic cells, but has been shown to be overexpressed in cancer cells, allowing them to divide indefinitely. The firm Pharmex has developed a vaccine called GV1001, a peptide vaccine that is engineered to illicit a response to the enzyme telomerase. In theory this vaccine could be used as a universal vaccine, since cancerous cells need Telomerase to survive. It is currently being developed in numerous cancer populations.

    The immunotherapeutic vaccine, AE37, is being developed by Generex' Antigen Express division in the US. The phase II study will enroll patients who have completed standard therapy for node-positive or high-risk node-negative breast cancer expressing at least low levels of the HER-2/neu oncogene. These patients are at an increased risk for recurrence; therefore, the endpoint for this study will be a 50% reduction in the rate of relapse of disease at two years.

    The immunotherapeutic agent being developed by Antigen Express is a peptide derived from a tumor-associated protein that has been modified to enhance stimulation of CD4+ T helper cells. The target protein is encoded by the HER-2/neu oncogene, which has been found to be over-expressed in a variety of tumors, including breast, ovarian, prostate, lung, colon, stomach and pancreas.

This article covers 5 clinical trials in various stages.

     The GM-CSF (granulocyte-macrophage colony-stimulating factor) Tumor Cell vaccine is part of the GVAX suite of vaccines from Cell GeneSys. The vaccine works through the injection of irradiated, non-growing prostate cancer cells that secrete GM-CSF. The GM-CSF acts to recruit the immune cells (specifically dendritic cells) to the site of the vaccine and produce an immune response. The immune response then acts to target any prostate cancer cell within the body. This vaccine is in clinical phase III trials and currently recruiting. The phase II trials, the time to disease progression in metastaticterm bone disease was almost doubled in treated patients.

Clinical trials of a breast cancer vaccine have begun.

BN ImmunoTherapeutics, Inc., a development-stage biotechnology company, today announced that the Food and Drug Administration (FDA) has accepted its Investigational New Drug Application (IND) for the company's investigational breast cancer vaccine, MVA-BN(R)-HER2. A clinical study of MVA-BN(R)-HER2 will begin enrollment at multiple clinical sites in the U.S. in early 2007, and a parallel trial is expected to commence in Europe shortly thereafter. MVA-BN(R)-HER2 will be tested in numerous clinical settings to determine how to best incorporate it into standard therapy for the treatment of metastaticterm breast cancer. This will include treatment with MVA-BN(R)-HER2 in combination with trastuzumab (Herceptin(R)) and chemotherapyterm.

Getting a vaccine "shot" is the best way to prevent infections like tetanus, polio, and measles. These vaccine shots stimulate your immune system (antibodies and T cells) to fight off the germs that cause these diseases.

New kinds of experimental vaccines are now being studied as treatments for non-Hodgkin's lymphomaterm (NHL). These vaccines are not designed to prevent lymphoma, but rather treat it once it has arisen, and are thus termed "therapeutic vaccines." As with other types of so-called immunotherapy (e.g., therapeutic monoclonal antibodies), lymphoma vaccines are designed to work by harnessing the power of a patient's own immune system to fight off his or her tumor.