GPI-1485 belongs to a class of small molecule compounds called neuroimmunophilin ligands. This class of compounds has been shown to repair and regenerate damaged nerves without affecting normal, healthy nerves. GPI-1485 binds to FK-506-binding proteins. Phase 2 studies have been conducted to assess whether GPI-1485 is able to delay or stop disease progression and improve symptoms in patients with Parkinson's disease (PD), and whether GPI-1485 can help preserve erectile function after prostatectomy.