[Pharmacological characteristics and clinical study results of danicopan (Voydeya^® tablets)]

Danicopan (brand name: Voydeya^® tablets) is a new oral small molecule complement factor D inhibitor that was approved in Japan in January 2024 for paroxysmal nocturnal hemoglobinuria (PNH). PNH is a rare, chronic hematologic disorder caused by acquired mutations of hematopoietic stem cells in the PIGA gene. These mutations cause deficiencies in complement regulatory proteins CD55 and CD59 that may lead to uncontrolled terminal complement activation, intravascular hemolysis, thrombosis, and premature mortality. Complement C5 inhibitors (C5i; eculizumab and ravulizumab) are the current standard of care of PNH treatment, and control intravascular hemolysis (IVH) by inhibiting terminal complement pathway activation. However, extravascular hemolysis (EVH) with persistent symptoms, such as anemia, occurs in some C5i-treated patients with PNH. EVH is caused by the accumulation of proximal complement C3 fragment on the membrane of surviving PNH-type red blood cells. These cells subsequently undergo phagocytosis in the spleen or liver. Danicopan was developed to control EVH by targeting complement factor D involved in alternative pathway activation. Preclinical studies showed that danicopan selectively inhibits alternative complement pathway activation by reversibly binding to factor D and inhibiting its serine protease activity. A global phase III study (ALPHA study: ALXN2040-PNH-301 [NCT04469465]) investigated danicopan as add-on therapy to ravulizumab or eculizumab in patients with PNH and clinically significant EVH. Danicopan achieved statistically significant, clinically meaningful increases in hemoglobin levels, reduced transfusion, and reduced fatigue, while maintaining control of IVH. No new safety concerns were observed. Danicopan makes it possible to control EVH while controlling IVH with C5i.