The Immune Response Corporation, a biopharmaceutical company developing immune-based therapies (IBT) for HIV and select other diseases, announced that its investigational T-cell receptor (TCR) peptide vaccine, NeuroVax, produced a peptide-specific immune response in 94 per cent of the patients treated in a Phase I/II clinical trial in multiple sclerosis.

Results of the three-armed, randomized trial, which was discontinued early when an interim analysis revealed the high rate of response, were presented last week at the 54th annual meeting of the American Academy of Neurology (AAN) held in San Francisco, CA.

Earlier clinical research on immunotherapy for multiple sclerosis suggested that only about half of patients had an immune response to treatment with a single TCR peptide but that this reaction probably had clinical benefit. NeuroVax is composed of a combination of TCR peptides from three families (BV5S2, BV6S5, and BV13S1) with an adjuvant to improve immune response rates.

"The surprisingly high immunogenic response to NeuroVax, both in the percentage of patients responding and in the strength of their responses, validates this new approach to enhancing TCR peptide immunization and suggests that we may finally be able to more specifically regulate the pathogenic T-cells thus addressing the underlying causes of the disease," said Dennis N. Bourdette, MD, chairman of the Department of Neurology at Oregon Health & Science University in Portland, Ore., and lead investigator for this study. "Patients with multiple sclerosis currently have few treatment options. Our research is continuing to determine if the active immune response to NeuroVax correlates with a clinically relevant impact on disease progression."

In the study, 37 patients were randomized to receive either the three TCR peptides with saline (15 patients), the NeuroVax combination (16 patients), or adjuvant alone (6 patients). Patients received monthly injections for 24 weeks, and the induction of TCR peptide-specific T-cell responses was measured against baseline to gauge immune response. Using an intent-to-treat analysis, the proportion of patients who were TCR vaccine responders was significantly greater (p<0.001) in the NeuroVax group, with 15/16 (94 per cent) responding patients compared with 1/15 (7 per cent) for the TCR/saline group and 0/6 for the adjuvant group.

"With 94 per cent of patients showing a disease-specific immune response in this study, we will continue to pursue development of NeuroVax in multiple sclerosis as both a monotherapy and in combination with currently approved treatments," said John N. Bonfiglio, CEO of The Immune Response Corporation. "NeuroVax is another example of how immune-based therapies pioneered by The Immune Response Corporation's co-founder, Dr. Jonas Salk, may provide a promising new mechanism for fighting difficult diseases.