In the not approvable letter FDA expressed concern if the efficacy findings support clinical utility of istradefylline (KW-6002). FDA requested an overall summary of nonclinical mineralization findings. Additionally, FDA asked for clinical pharmacology follow-up information as a Phase IV commitment. After closely examining the FDA’s response, Kyowa Hakko will work closely with FDA and conduct a comprehensive discussion to determine a path forward for istradefylline.
Istradefylline has a novel mechanism of action that antagonizes the adenosine A2A receptor. It has been under FDA review as adjunctive therapy to levodopa and carbidopa for the treatment of idiopathic Parkinson’s disease to improve motor function in patients who experience motor response complications.