A clear unmet medical need in allergic respiratory diseases is that of an effective and safe oral therapy targeting simultaneously both allergic asthma and rhinitis. While agents blocking histamine H₁ receptor have been widely used in the treatment of allergic rhinitis, they lack efficacy in the treatment of asthma. Leukotriene antagonists may be used in both pathologies; however, their efficacy is very limited.

The histamine H₄ receptor (H₄R) is a G-protein coupled receptor that is highly expressed in bone marrow and white blood cells. Its distribution and data from several preclinical in vitro and in vivo proof-of-principle studies suggest that this novel target plays a key role in allergic and immuno-inflammatory disorders.

An orally administered and highly safe H₄R antagonist blocking the allergic process and the airway inflammation in both the nose and the bronchi would be a revolutionary therapeutic contribution, and may substantially improve the control of the disease in patients with coexistence of asthma and rhinitis.

Palau’s H₄R antagonist, UR-63325, has been designed to fill this niche. The compound has recently completed the Phase I single rising dose clinical trial, and has shown to be safe and well tolerated. Furthermore, an H₄R-dependent blood biomarker has provided the first pharmacodynamic assessment with the scheduled regimen.

UR-63325 is currently in Phase I multiple dose clinical trial. Results of the study are due in Q4 2010.

Palau is seeking to establish a creative and value-driven strategic alliance with a leading biopharmaceutical company for the late stage development and commercialization of UR-63335.