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Phase 2 Trial of R112 Fails To Show Statistically Significant Difference Compared to Placebo Treatment in Nasal Allergy Symptoms
"We are disappointed in today's results," said James M. Gower, chairman and chief executive officer of Rigel. "These results are surprising given that the earlier Phase II 'Park' study of R112 demonstrated a statistically significant reduction in the symptoms associated with allergies."
Study Details and Prior Phase II Results
The Phase II study was conducted at 25 centers across the United States and enrolled 396 patients who had experienced seasonal allergic rhinitis during the summer/fall pollen season for the last two years. The primary endpoints were safety and efficacy, as measured by a total nasal symptom severity (TNSS) rating scale, a scale of five nasal symptoms including congestion, runny nose, sneezing, itchy nose and postnasal drip. The trial consisted of a screening period during which the patients stopped taking any allergy medications, followed by a placebo run-in period. The patients were then randomized to a 7-day treatment cycle of twice daily dosing of R112, placebo or Beconase AQ.
In an earlier Phase II "Park Study" clinical trial, R112 demonstrated statistically significant efficacy in improving symptoms of allergic rhinitis, including sneezing, stuffy nose, running nose, itchy nose, itchy throat, post nasal drip, cough, headache and facial pain, and had a rapid onset of action as early as 30-45 minutes over a two day period. In all clinical studies to date, R112 has been shown to have a favorable safety profile.
Allergic Rhinitis: Role of Immune Mediators and Current Treatments
Allergic rhinitis involves inflammation of the mucous membranes of the nose, eyes, ear, sinuses and pharynx. This inflammation is characterized by a complex interaction of inflammatory mediators, but ultimately is triggered by an immunoglobulin E (IgE)-mediated response to a foreign allergen. When a specific allergen (e.g., pollen) is inhaled into the nose, it can bind to the IgE on mast cells present in the mucus membranes. This leads to immediate and delayed release of a number of mediators, which can ultimately lead to common allergic symptoms. These mediators include histamine, tryptase, chymase, kinins, heparin, leukotrienes and PGD2.
Common allergy drugs such as antihistamines or antileukotrienes block only a single mediator. Intranasal steroids are able to block multiple mediators in the allergic response, but these can have a slow onset of action and sometimes require multiple days of treatment before a positive effect is seen. Despite the drawbacks of these treatments, the U.S. market for allergic rhinitis therapies approaches $4 billion
Source: Rigel Pharmaceuticals