Voxelotor Tablets for Sickle Cell Disease Granted Accelerated Approval by FDA

The FDA has granted accelerated approval to voxelotor tablets (Oxbryta, Global Blood Therapeutics) for the treatment of sickle cell disease (SCD) in adults and pediatric patients 12 years of age and older. 

Voxelotor is a once-daily oral therapy hemoglobin S polymerization inhibitor. According to a statement from GBT, inhibiting hemoglobin polymerization may slow the breakdown of RBCs and improve anemia and reduce the complications of SCD. 

“Every person with SCD experiences hemoglobin polymerization and suffers from varying severity of anemia and hemolysis,” said Elliott Vichinsky, MD, director of hematology/oncology at UCSF Benioff Children’s Hospital in Oakland, CA, in a statement. “With today’s approval of Oxbryta, we now have a therapy that significantly improves hemoglobin levels, has a favorable safety profile and reduces the anemia and hemolysis that inevitably leads to the long-term and often undetected detrimental effects associated with this chronic genetic condition.”

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Approval was based upon results of a phase 3 randomized trial comparing voxelotor to placebo, published in the New England Journal of Medicine in June 2019. The trial included 274 patients 12 years of age and older with SCD. 

Primary efficacy was measured as a greater than 1 g/dL of hemoglobin increase after 24 weeks. 

• Oxbryta arm: 51.1% of patients 

• Placebo: 6.5% of patients

Since voxelotor was granted accelerated approval, GBT said in a statement that continued approval is contingent upon verification and description of clinical benefit in confirmatory trials. 

Voxelotor is contraindicated in patients with a known hypersensitivity to the active ingredient or any of Oxbryta’s excipients. 

Aside from hypersensitivity reactions, voxelotor’s prescribing information warn of interference with laboratory tests. Hemoglobin quantifications should be performed when patients are not taking voxelotor. 

Full Prescribing Information