Two years after starting to receive four doses of a cat allergy treatment, patients continue to show fewer signs of itching eyes and nose, watery eyes and sneezing, say McMaster researchers.

The second phase of a clinical trial of a therapy to treat cat allergies demonstrates just four doses of the treatment, showed significant improvements in patients' symptoms two years after the start of the therapy.

Mark Larché, professor of medicine at the Michael G. DeGroote School of Medicine and Canada Research Chair in Allergy and Immune Tolerance, presented results at the annual meeting of the American Academy of Allergy, Asthma and Immunology in San Antonio, Texas on Sunday.

In the study, 202 patients were provided the treatment or a placebo over 12 weeks and 50 of the original patients returned in 24 months to be re-assessed for symptoms while exposed to cat allergens. The patients who had taken four doses of the treatment maintained a substantial reduction in symptoms throughout their entire exposure to cat allergens over four days.

Larche said the treatment could be available in two years if studies continue to be successful

"Sustaining such a substantial improvement in patients' allergy symptoms two years after the start of the study is remarkable," Larché said. "Achieving this with a short course of just four doses is even more impressive. These results suggest that the therapy has the potential to revolutionize treatment for cat allergy patients."

The clinical development of the treatment was undertaken by Adiga Life Sciences, a joint business venture between McMaster and Circassia Ltd., a UK-based biotech company. The study is now in its third phase.

Larché is also a researcher with the Firestone Institute for Respiratory Health and holds the McMaster University/GlaxoSmithKline Chair in Lung Immunology at St. Joseph's Healthcare Hamilton.