Allergy immunotherapy - AIC
Pollen allergies make life a misery for sufferers in the summer. Typically treated with drugs such as antihistamines, corticosteroids and antileukotriene agents, the only answer for the afflicted is sometimes simply to stay indoors away from the source of the allergens.
Pollen allergies make life a misery for sufferers in the summer. Typically treated with drugs such as antihistamines, corticosteroids and antileukotriene agents, the only answer for the afflicted is sometimes simply to stay indoors away from the source of the allergens.
In extreme cases, immunotherapy can provide help, and now US company Dynavax is developing a new form of immunotherapy that could prove a lifeline for sufferers.
AIC is a combination of the company's immunostimulatory sequence 1018 ISS linked to the purified major allergen of ragweed, Amb a 1. AIC targets the underlying cause of seasonal allergic rhinitis caused by ragweed, and the aim is to help the body fight off the allergic reactions.
ISS is a short, synthetic string of DNA bases that stimulate a Th1 immune response while suppressing Th2 immune responses, and activate the innate immune system. They influence helper T cell responses in a targeted, highly specific manner, by only redirecting the response of the T cells that are involved in a given disease; meaning that they do not alter the immune system's ability to mount an appropriate response to infecting pathogens, and do not cause a generalised activation of the immune system. By chemically linking ISS to allergens that are known to cause specific allergies, rather than merely mixing them, a better Th1 response is achieved.
In a Phase I single centre, double blind, placebo controlled dose ranging clinical trial, 18 subjects who were allergic to ragweed were randomised in a ratio of 2 to 1 to receive AIC or placebo.1 The treated group received seven injections over seven weeks, with doses either escalating from 0.3 to 30µg or 1.2 to 30 µg. AIC was found to be well tolerated and safe, with no serious local or systemic adverse events being observed. It also showed that treatment with AIC prior to a single ragweed season at a peak dose substantially exceeds what can safely be used with conventional immunotherapy - 30µg compared with 6µg.
Trials are continuing, including a Phase II/III clinical study. ISS is also being investigated in combination with other agents for a variety of therapeutic uses, including hepatitis B surface antigen.