Global Blood Therapeutics, Inc., a biopharmaceutical company developing novel therapeutics for the treatment of grievous blood-based disorders with significant unmet needs, announced that the US Food and Drug Administration (FDA) has granted Orphan Drug designation for GBT440 for the treatment of patients with sickle cell disease (SCD). GBT440 is being developed as a potentially disease-modifying therapy for SCD.

“Receiving orphan drug designation, along with the previously announced Fast Track designation, are important milestones in our regulatory strategy for GBT440 and highlight the FDA’s agreement that the SCD community faces a critical need for new treatments,” said Ted W. Love, M.D., chief executive officer of GBT.

“We continue to believe that GBT440 has the potential to become the first mechanism-based and disease-modifying therapeutic for this grievous disease and look forward to sharing full results from our phase 1/2 trial and potentially initiating a pivotal trial in adult patients with SCD in 2016.”

The FDA’s Orphan Drug designation programme provides orphan status to drugs and biologics that are being developed to address rare diseases or disorders that affect fewer than 200,000 people in the US. With orphan designation, GBT qualifies for various incentives, including tax credits for qualified clinical trials and market exclusivity upon regulatory approval.

GBT440 is being developed as an oral, once-daily therapy for patients with sickle cell disease. GBT440 works by increasing hemoglobin’s affinity for oxygen. Since oxygenated sickle hemoglobin does not polymerize, the company believes GBT440 blocks polymerization and the resultant sickling of red blood cells (RBCs). With the potential to restore normal hemoglobin function and improve oxygen delivery, GBT440 may be capable of modifying the progression of SCD.

SCD is an inherited blood disorder caused by a genetic mutation in the beta-chain of hemoglobin, leading to formation of abnormal hemoglobin known as sickle hemoglobin, or HbS. In its deoxygenated state, HbS has a propensity to polymerize, or bind together forming long, rigid rods within a red blood cell (RBC). The polymer rods deform RBCs to assume a sickled shape and to become inflexible, which can cause blockage in small blood vessels. Beginning in childhood, SCD patients suffer unpredictable and recurrent episodes or crises of severe pain due to blocked blood flow to organs, which often lead to psychosocial and physical disabilities. This blocked blood flow, combined with hemolytic anemia (the destruction of RBCs), can eventually lead to multi-organ damage and early death.