Synthetically Designed Immunotherapy Cancer Vaccines
Antigen Express is the fully owned life science subsidiary of Generex Biotechnology (GNBT). Antigen Express is building an impressive pipeline of next generation synthetic therapeutics aimed at a variety of major diseases, including cancer and infectious diseases. The platform technology of Antigen Express allows for antigen-specific stimulation of a T-helper response to virtually any antigen of known pathogenic potential. Antigen Express is currently evaluating its leading candidate, the novel Ii-key hybrid HER2/neu peptide AE37 vaccine, in a multi-center Phase II trial for patients with breast cancer under a research agreement with the United States Military Cancer Institute.
AE37 is an immunotherapeutic synthetic peptide vaccine designed to prevent the recurrence of a variety of different cancers that express the HER-2/neu peptide. An advantage of Antigen Express' immunotherapy is that it causes none of the toxicities typically associated with classical chemotherapy. While the target of AE37 is the same as that of the Roche's (RHHBY.PK) blockbuster cancer drug Herceptin, the activity of AE37 relies on its ability to stimulate a patient's own immune system to recognize the cancer target rather than by interacting with the target directly.
New AE37 Data to be Presented at ASCO 2010
I found evidence that new data for the AE37 vaccine will be presented at the 2010 American Society of Clinical Oncology Annual Meeting to be held in Chicago from June 4-8, 2010. ASCO 2010 abstracts will be available on the company's Annual Meeting website in mid-May, although abstract titles can currently be found on the event itinerary page. The title of an AE37 abstract being presented at ASCO 2010 is Effect of a Novel Ii-key Hybrid HER2/neu Peptide AE37 Vaccine with GM-CSF as Compared to GM-CSF Alone on Levels of Regulatory T-cell Treg Populations. The listed author/speaker is Dr. Guy T Clifton, who has worked extensively on peptide based therapeutic vaccines at the USMCI with Antigen Express collaborator Col. George Peoples.
If Dr. Clifton highlights Phase II data that confirms previously reported Phase I data regarding AE37's effect on regulatory T-cell Tregs, that would be great news for Antigen Express. The Phase I trial for AE37 in breast cancer patients showed that Tregs were reduced in all patients tested pre- to post-vaccination. This smaller Phase I trial also found that DTH responses increased in all patients from pre- to post-vaccination p<0.0001. Boding well in this trial for the vaccine was that there was an inverse relationship between the degree of Treg reduction and the size of DTH response to AE37. The researchers concluded in this trial that the reduced levels of Tregs in vaccinated patients appear to be associated with more robust responses in ex vivo immune assays and in vivo DTH reactions suggesting that the AE37 vaccine may be clinically useful.
This pending update follows the impressive interim results for the AE37 vaccine in its current Phase II trial which were unveiled at the San Antonio Breast Cancer Symposium in December 2009. Two hundred disease-free, high risk, breast cancer patients who had completed standard adjuvant therapy are being enrolled and randomized to receive six monthly inoculations of either the AE37 peptide vaccine or the adjuvant GM-CSF alone to compare their ability to prevent cancer recurrence. This interim analysis followed the first 49 patients in the AE37 group and the first 71 for the control group. At a median follow up of 13 months, there were no (0.0%) recurrences in the AE37 group of patients, 0/49, compared to 7.0%, 5/71, in the control group.
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