FDA Grants Breakthrough Therapy Designation to Voxelotor

Voxelotor, a potential treatment for sickle cell anemia (SCA), has been given breakthrough therapy designation (BTD), Global Blood Therapeutics (GBT) recently announced.

Voxelotor (previously called GBT440) is a potential once-daily oral medicine for SCA patients. It was designed to increase hemoglobin’s binding of oxygen, which keeps red blood cells in their normal round shape, and helps prevent cells’ clumping and sickling.

GBT believes that the ability to repair hemoglobin function and improve oxygen delivery makes voxelotor a potential disease-modifying therapy in SCA. The medicine previously was granted fast track, orphan drug (given to promising products for the diagnosis and/or treatment of rare diseases) and rare pediatric disease designations.

The U.S. Food and Drug Administration (FDA) grants BTD to therapies for serious or life-threatening diseases if they show substantial improvement over existing medications in preliminary clinical results. The BTD label accelerates development and review of the new treatment.

The clinical data backing up volexotor’s potential was otained from multiple studies. The ongoing multi-center Phase 3 HOPE study (NCT03036813) in SCA patients 12 to 65 years old showed positive efficacy and safety data. The study is still recruiting patients.

BTD also was based in results from a Phase 1 trial (NCT02285088) and its Phase 2 extension in adults (NCT03041909), and in the ongoing Phase 2 HOPE-KIDS 1 study (NCT02850406) in children 6 to 17 years old. This study is being conducted in the U.S. and also is recruiting patients.

“The FDA’s decision to grant voxelotor the first [BTD] for the treatment of [SCA] reflects a recognition of the promising efficacy and safety data we have collected to date for this investigational drug,” Ted W. Love, president and CEO at GBT, said in a press release. The designation also is “an acknowledgement of the overwhelming need for major advances over available therapies in the treatment of [SCA] patients.”

The European Medicines Agency had granted volexotor Priority Medicines (PRIME) designation to treat SCA. This is a mechanism to speed up development of medicines that target unmet medical needs.

SCD is an inherited condition that begins in childhood, characterized by insufficient healthy hemoglobin to carry oxygen in the body. The disease is caused by a mutation in the gene coding for the hemoglobin, which leads to the formation of an abnormal protein. When it is not bound to oxygen, this defective hemoglobin may form clumps and alter the shape of red blood cells, which can block blood vessels. As a result, patients may experience severe pain, leg ulcers, organ damage, stroke, and/or pulmonary hypertension.