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A breast cancer vaccine already shown to elicit a powerful immune response inwomen with varying levels of HER2 expression has the ability toimprove recurrence rates and is well tolerated in an adjuvantsetting, according to new research from a clinical trial led byresearchers at The University of Texas MD Anderson Cancer Center. The findings will be presented on Monday, June 4 in an oralpresentation at the 2012 Annual Meeting of the American Society ofClinical Oncology (ASCO). It builds on previous research showingthe vaccine, known as AE37, to safely and effectively raiseimmunity against human epidermal growth factor receptor 2 (HER2) -an oncoprotein that promotes tumor growth and is expressed to someextent in 75-80% of breast cancer tumors. The researchers found that patients who received the vaccinationhad an estimated recurrence rate of 10.3% compared to 18% in thecontrol group at a median follow up of 22 months. This representeda 43% reduction in the risk of recurrence. "The vaccine educates the immune system to recognize HER2 as aninvader," said Elizabeth Mittendorf, M.D., assistant professor inthe Department of Surgical Oncology at MD Anderson and the trial'snational principal investigator. "By introducing it into women whohave had breast cancer, our goal is to instruct the immune systemto immediately recognize any recurring cancer cells and orchestrate an attack." Building a Powerful Vaccine The AE37 peptide vaccine used in this study is a hybrid modified toincrease its potency in generating an immune response specific tocancer cells expressing HER2. It consists of a fragment of the HER2protein (AE36), a MHC Class II epitope, linked to an Ii-Keypeptide. Together, they work to stimulate a robust CD4+ T cellresponse, prompting the components of the immune system to seek anddestroy tumor cells. To help T cells better recognize AE37, researchers also paired thevaccine with an immune stimulant known as granulocyte/macrophagecolony stimulating factor (GM-CSF). The vaccine is injected underthe skin similar to a tetanus shot. The initial series consists of inoculations given monthlyfor six months followed by four cycles of boosters every sixmonths. Preventing Breast Cancer Relapse Most experimental drugs are first evaluated in patients withmetastatic disease, when tumors have undergone drastic changes,including immunoescape - a mechanism that allows tumor cells toevade elimination by the immune system. "There's very little chancea single peptide vaccine like AE37 will overcome a tumor at thisstage of disease," said Mittendorf. "For this reason, it's morerealistic to use the vaccine to prevent recurrence rather than totreat a large mass of already present cancer cells." In the Phase II randomized clinical trial of 201 disease-freebreast cancer patients, 103 women received the AE37 peptide plusGM-CSF adjuvantly; a control group of 98 patients received GM-CSFalone. All patients had varying levels of HER2 expression. Results showed that the vaccine was well tolerated in the patientsand toxicity was minimal; short-term side effects included rednessat the injection site, flu like symptoms and bone pain. In addition to being consistent withearlier data which showed a significant immune response to thevaccine, the study also revealed how the vaccine affects recurrencerates. The vaccine appears to prevent recurrence and work in women withany level of HER2 expression. Further, the findings draw parallelsto other vaccines we now have advanced to later phase trials,Mittendorf said. MD Anderson currently has three different types ofHER2-based peptide vaccines in various stages of testing anddevelopment. AE37 is the only one that targets CD4+ T cells. "Off the Shelf" Capability Among the benefits of a peptide-based vaccine are that it's simpleto produce and administer, and that it can be easily exported tothe community compared to other available vaccines. Mittendorfnoted whereas dendritic cell vaccines require patients to go to thehospital for a large blood draw that is shipped to a processingcenter - a complicated and expensive process - peptide vaccines canbe administered to patients "off the shelf." The vaccine possibly offers advantages to today's adjuvanttherapies as well. "Adjuvant therapies currently used for breastcancer are taken ongoing. Otherwise, their effect to block cancerdevelopment is diminished," said Mittendorf. "In theory, once aresponse is generated with immunotherapy, we can expect a longerlasting therapeutic effect without repeated dosing. "This is an exciting time for immunotherapy as we transferknowledge from the lab to clinic. There's a renewed enthusiasm tomanipulate the immune system therapeutically - from vaccines andantibodies to combining these modalities and improving responserates." The findings will be presented at ASCO by Timothy J. Vreeland,M.D., resident at Brooke Army Medical Center. The trial is fundedin part by Antigen Express, the company that licenses the vaccinetechnology. Based on this study, Antigen Express plans to apply fora special protocol assessment from the US Food and DrugAdministration to continue Phase III research needed on thevaccine. Additional References Citations. The e-commerce company in China offers quality products such as IPad 2 Digitizer Replacement , IPod Flex Cable Manufacturer, and more. For more , please visit IPod Video LCD Replacement today!
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