Asimadoline — A Novel Therapy for the Treatment of Pruritus
- Asimadoline is an orally active, highly selective kappa-opioid receptor agonist with approximately 500-fold greater affinity for human kappa-, as compared with either delta- or mu-opioid receptors. Due to its high selectivity for the kappa-opioid receptor, asimadoline does not produce mu-opioid like side-effects.
- Asimadoline has been administered to over 1900 human subjects or patients in clinical trials and exhibits an acceptable safety profile.
- Asimadoline has demonstrated efficacy in animal models of pruritus by significantly reducing the frequency of scratching induced by intra-dermally injected Substance P and significantly inhibiting scratching behavior induced by intra-dermally injected histamine or dinitrofluorobenzene.
- Due to its mechanism of action, asimadoline has the potential to treat pruritus associated with a variety of conditions, including atopic dermatitis, psoriasis, end-stage renal disease, liver diseases such as cholestatic disease and primary biliary cirrhosis, malignancies, adverse drug effects, and certain orphan diseases.
- Tioga Pharmaceuticals is conducting a Phase 2 Proof-of-Concept clinical study of asimadoline for the treatment of pruritus associated with atopic dermatitis. The double-blind, placebo-control clinical study is designed to evaluate the safety, tolerability, and clinical efficacy of asimadoline and is being conducted at approximately 20 clinical study centers in the US. For more information please refer to
- Pruritus, or itch, is an unpleasant sensation that provokes the desire to scratch and can range from a mildly annoying to an intractable debilitating condition. Chronic pruritus (defined as lasting six weeks or more) is associated with significant decrease in quality of life, including impact on sleep, anxiety, depression, and ability to work and lacks effective treatment options.
- Chronic pruritus may be associated with many illnesses, including renal, liver, dermatological, or systemic diseases. Chronic pruritus is estimated to occur in approximately 20% of the general population world-wide, with a very high incidence in certain dermatological and systemic conditions.
- The kappa-opioid system plays a pivotal role in the sensory transmission and processing of itch sensation from the skin to the brain. Decreased kappa-opioid receptor activation or down regulation, coupled with increased mu-opioid receptor activation, have been demonstrated in animal models of chronic pruritus. Nalfurafine, a selective kappa-opioid agonist similar to asimadoline, has demonstrated efficacy in reducing refractory pruritus associated with end-stage renal disease and is approved (Remitch®; Toray Industries, Inc.) for this indication in Japan.