C5 and paroxysmal nocturnal hemoglobinuria: Ravulizumab, the first long-acting complement inhibitor, which was recently approved for the treatment of PNH in the USA (December 2018), Japan (June 2019), Europe (July 2019), Canada (August 2019), and Brazil (September 2019), provides immediate, complete, and sustained inhibition of C5 with an 8-week dosing interval [8, 9, 12–14].