Drug development stage of FDA and EMA OD for SCD categorized by pathophysiological targets and phase of the drug development reached. Blue symbols at the right end of the histograms represent ongoing ODs, red symbols represent discontinued ODs, and green symbols represent ODs approved either in the United States or in the EU. ODs granted by the FDA; ODs granted by the EMA; ∗approved in the EU but outside the orphan system; ◊ approved in the United States also for the pediatric population; ⦿ approved in the United States but negative opinion in the EU; ▲ first approved in both the United States and the EU; after a referral, the EMA revoked the marketing authorization in the EU; ◆ approved in the United States but outside the orphan system. DDFPe, dodecafluoropentane emulsion; FCT, film-coated tablets; HU, hydroxyurea; OLF, oral liquid formulation; PPF, powder for pharmaceutical formulation; PPS, pentosan polysulfate sodium.