FDA Breakthrough Therapy Designation Granted to Potential Sickle Cell Disease Treatment

This morning, Global Blood Therapeutics, Inc. (GBT) was granted Breakthrough Therapy Designation from the U.S. Food and Drug Administration (FDA) for voxelotor for the treatment of sickle cell disease (SCD).

Voxelotor, previously called GBT440, is in development as a disease-modifying therapy and previously received Priority Medicines (PRIME) designation from the European Medicines Agency (EMA) for the same indication. Two years ago, it was granted orphan drug designation from the FDA.

SCD is a rare genetic condition in which patients have red blood cells that are hard, sticky, and C-shaped. These abnormal cells clog smaller blood vessels, resulting in excruciating pain and an increased risk for infection, acute chest syndrome and stroke. GBT believes that voxelotor can prevent sickling by blocking hemoglobin (HbS) polymerization with maintenance of HbS in the oxygenated state. The disease-modifying drug has the potential to restore normal HbS function and improve the delivery of oxygen.

“The FDA’s decision to grant voxelotor the first Breakthrough Therapy designation for the treatment of sickle cell disease reflects a recognition of the promising efficacy and safety data we have collected to date for this investigational drug, as well as an acknowledgement of the overwhelming need for major advances over available therapies in the treatment of SCD patients,” said Ted W. Love, president and chief executive officer of GBT in a press release. “This designation is another significant milestone for GBT as we work to expedite the development of voxelotor.”

The decision to grant voxelotor Breakthrough Therapy designation was based on clinical data submitted from 4 studies, including: Preliminary efficacy and safety data from Part A of the Phase 3 HOPE Study; Phase 1/2 study and open-label extension in adults; Ongoing Phase 2 HOPE-KIDS 1 study in children age 6 to 17; and Compassionate Access experience in adults with severe SCD (not eligible for the HOPE study).

Voxelotor is currently being evaluated in the HOPE (Hemoglobin Oxygen Affinity Modulation to Inhibit HbS PolymErization) Study, a Phase 3 clinical study in patients age 12 and older with SCD. Additionally, it is being studied in the ongoing Phase 2a HOPE-KIDS 1 Study, an open-label, single- and multiple-dose study in pediatric patients (age 6 to 17) with SCD. HOPE-KIDS 1 is assessing the safety, tolerability, pharmacokinetics and exploratory treatment effect of voxelotor.

Voxelotor is being developed as an oral, once-daily therapy.

For more from the FDA, including applications, designations and approvals, follow Rare Disease Report on Facebook and Twitter.