Tradipitant is being evaluated in a Phase II study in treatment resistant pruritus in atopic dermatitis.
Tradipitant is an NK-1 receptor antagonist licensed from Eli Lilly in 2012. Tradipitant has demonstrated proof-of-concept in alcohol dependence in a study published by the NIH1. In that study tradipitant was shown to reduce alcohol cravings and voluntary alcohol consumption among patients with alcohol dependence. NK-1R antagonists have been evaluated in a number of indications including chemotherapy-induced nausea and vomiting (CINV), post-operative nausea and vomiting (PONV), alcohol dependence, anxiety, depression, and pruritus.
The NK-1R is expressed throughout different tissues of the body, with major activity found in neuronal tissue. Substance P (SP) and NK-1R interactions in neuronal tissue regulate neurogenic inflammation locally and the pain perception pathway through the central nervous system. Other tissues, including endothelial cells and immune cells, have also exhibited SP and NK-1R activity2. The activation of NK-1R by the natural ligand SP is involved in numerous physiological processes, including the perception of pain, behavioral stressors, cravings, and the processes of nausea and vomiting1,2,3. An inappropriate over-expression of SP either in nervous tissue or peripherally could result in pathological conditions such as substance dependence, anxiety, nausea/vomiting, and pruritus1,2,3,4. An NK-1R antagonist may possess the ability to reduce this over-stimulation of the NK-1R, and as a result address the underlying pathophysiology of the symptoms in these conditions.