A regimen of six weekly shots of a novel vaccine may be an effective long-term approach for patients with allergic rhinitis, sparing them injections once or twice a week for three to five years, according to results of a pilot study published recently in the New England Journal of Medicine. The treatment, Amb 1-immunostimulatory oligodeoxyribonucleotide conjugate (AIC), combines a ragweed-pollen antigen (Amb a 1) that sets off the allergic reaction with a synthetic bit of DNA (phosphorothiotate oligodeoxyribonucelotide immunostimulatory sequence) that stimulates the immune system.
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January 2007“This pilot study suggests that the clinical effects of AIC appear to be associated with the mechanism of long-lasting immune modulation…. This approach may also be applicable to other substances that lead to allergic reactions,” according to lead author of the study, Peter S. Creticos, MD, who is Associate Professor of Medicine in the Department of Medicine, Division of Allergy and Clinical Immunology, at the Johns Hopkins University School of Medicine in Baltimore.
The randomized, double-blind, placebo-controlled Phase II trial included 25 adults with documented seasonal (fall) allergies to ragweed, 17 of whom completed the trial. Patients were 23 to 60 years old. All patients received six weekly injections before the onset of the first ragweed season and then were monitored during the next two ragweed seasons. AIC was prepared by the same company (Dynavax) and the same lot of standardized ragweed was used throughout the study. No additional injections were given, but patients were allowed to use medications to relieve eye and nasal symptoms that were difficult to tolerate.
AIC had no effect on the primary endpoint—vascular permeability response as measured by level of albumin, a marker of vascular leakage and inflammation that is reduced by standard allergen immunotherapy. However, AIC achieved impressive improvements in symptoms. During the first ragweed season, the group that received the AIC vaccine had improved peak-season rhinitis scores on the visual analog scale, peak-season daily nasal symptom diary scores, and midseason overall quality of life scores compared with the placebo group. A transient increase in Amb a 1-specific IgG antibody was observed in the AIC-treated group, along with a suppression of the seasonal increase in Amb a 1-specific IgE antibody. A reduction in the number of interleukin-4-positive basophils in patients who received the novel vaccine was correlated with lower rhinitis visual analog scores. In the second ragweed season, the clinical benefits of AIC were seen again, and the seasonal specific IgE antibody response was suppressed again, with no significant change in IgE antibody titer during the ragweed season. The novel vaccine appeared to be safe and well-tolerated. No pattern of vaccine-associated systemic reactions or clinically significant laboratory abnormalities was observed.