IMARA Inc, announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation for IMR-687 for the treatment of patients with β-thalassemia. The Orphan Drug Designation for IMR-687 was previously granted for the treatment of patients with sickle cell disease (SCD). IMR-687, is an oral, once-a-day, potentially disease-modifying treatment for SCD and β-thalassemia. It is a highly selective and potent small molecule inhibitor of PDE9 that has a multimodal mechanism of action that acts primarily on red blood cells and has the potential to act on white blood cells adhesion mediators and other cell types that are implicated in SCD. Blocking PDE9, HbF levels in red blood cells increased, improving symptomology and lowering disease burden in patients with SCD and β-thalassemia. Based on preclinical data, IMARA stated that IMR-687 has several features that make it an optimal therapeutic for SCD and β-thalassemia such as a highly potent PDE9 inhibitor, differentiated selectivity and tolerability profile, minimal brain penetration and drug product stability. More information can be found here.