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| |  ASH MEETING: Vaccine Produces Tumour-Specific Immune Responses FRAMINGHAM, MA -- December 8, 1997 -- Genzyme Transgenics Corp. announced today that its idiotypic cancer vaccine produced tumour-specific immune responses in six of seven follicular lymphoma patients treated in a phase I/II clinical trial being conducted at the National Cancer Institute (NCI). Larry Kwak, M.D., Ph.D., NCI principal investigator for the study, described these findings at the 39th annual meeting of the American Society of Hematology in San Diego. The tumour-specific responses shown by patients with low-grade follicular B-cell lymphoma indicate that the idiotypic vaccines used may reduce or eliminate cancer cells that remain following conventional therapies. The vaccine activated cellular immune responses in a particular group of T cells, CD8+ T cells, generating a type of cell-mediated immunity thought to play a critical role in the body's ability to attack and destroy tumour cells. The goal of therapy with these vaccines is to produce an effective, active immune response in the patient against their tumour. "Prior to vaccine therapy, no immune responses to their own tumours were observed among these patients," Dr. Kwak said. "These results provide evidence that T cells specific for autologous follicular lymphoma can be elicited with this formulation of lymphoma-derived antigen. We are particularly pleased with these results because activation of this group of T cells is a principal goal of our current phase II clinical trial." Idiotypic vaccines contain proteins, called immunoglobulins, derived from patient's own cancer cells. The vaccine is prepared while the patient is undergoing an initial course of chemotherapy. Following this chemotherapy, the vaccine is administered in five separate monthly doses along with another protein, GM-CSF, that boosts the immune system's response to the vaccine. In pilot and in the ongoing phase I/II study, the vaccine has not shown appreciable serious side effects. Monoclonal antibodies directed against proteins present on both normal and cancerous B-cells have also been used to treat follicular B-cell lymphoma. These antibodies provide only a passive, temporary immunity. The idiotypic vaccines used in this study generate immunity against proteins that are present only on the patient's cancer cells. This immunity is therefore both specific and active, that is, patients develop their own antibodies and/or T cells only against their cancer cells to eradicate them. This form of immunity is expected to prove longer lasting than passive immunity. B-cell lymphoma is a malignancy of B-lymphocytes, the antibody-producing cells of the immune system. While most patients who are treated for this form of blood cancer experience at least a partial remission following conventional chemotherapy, the disease is invariably fatal, with a median survival of from Approximately 100,000 individuals have low grade follicular B-cell lymphoma in the U.S. -- 50,000 have multiple myeloma. Both diseases are invariably fatal; survival rates for these diseases have not improved for the last 40 years despite the use of numerous types of chemotherapy.
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