For those with cat allergies, hope may just be around the corner for a vaccine that could relieve symptoms for up to two years. The final-stage trial results should be back in the hands of researchers by 2015. Over 1,200 patients participated in the final-stage trials. The U.S. Federal Drug Administration and the European Medicines Agency have both agreed that a single positive phase III trial will be sufficient for approval. The first two phases of trials were considered successful.
What is different about this new vaccine, when compared to currently available cat allergy vaccines, is that it uses peptide immunotherapy. Currently available vaccines use the whole protein of the allergen. The new vaccine uses a synthetic version of the protein, and isolates that part of the protein that causes the allergic reaction.
When this broken down protein is injected into the skin, the proteins turn off the T-cell reaction, which causes an allergic reaction, and the body builds up immunity to the allergen as a result.
The new vaccine will be administered in a series of four shots over a twelve-week period. Two-hundred and two patients were divided into two groups, one receiving the vaccine and one receiving a placebo. After the twelve week period of treatment, 50 patients were re-evaluated over a four day period, and those who had received the vaccine still had a significant decrease in allergy symptoms when exposed to the cat allergens.
The vaccine was developed at McMaster University in Hamilton, Ontario by a team led by Mark Larche. The UK biotech firm Circassia is also involved in the production and clinical trials of the vaccine.
Ramie A. Tritt, MD, President of Atlanta ENT
