FDA Grants Priority Review to Potential Sickle Cell Disease Treatment

Officials with the FDA have accepted and granted Priority Review for Global Blood Therapeutics’ New Drug Application (NDA) for voxelotor, an oral, once-daily treatment for sickle cell disease (SCD), according to a press release.

Previously called GBT440, voxelotor is being developed for patients with SCD and works by increasing hemoglobin’s affinity for oxygen. If approved, voxelotor would be the first therapy available to patients that targets hemoglobin polymerization, the driver of the pathophysiology of SCD.

The NDA acceptance is supported by data from the phase 3 HOPE study, which evaluated voxelotor in patients aged 12 years and older with SCD. In the study, 2 dose levels of voxelotor (1500 mg and 900 mg, administered orally once daily) were compared for efficacy and safety.

In total, 274 participants were randomized to receive either a once-daily oral dose of 1500 mg voxelotor, 900 mg of voxelotor, or placebo. Most patients in the study had sickle cell anemia and approximately two-thirds were receiving hydroxyurea at baseline.

In the intention-to-treat analysis, a significantly higher percentage of patients had a hemoglobin response in the 1500-mg voxelotor group than in the placebo group, according to the results. Additionally, fewer patients in the voxelotor dose group experienced worsened anemia between baseline and week 24 than in the placebo group.

At week 24, patients in the 1500-mg voxelotor group demonstrated significantly greater reductions from baseline in the indirect bilirubin level and percentage of reticulocytes than the placebo group, according to the study.

Most adverse events (AEs) that occurred were not related to voxelotor or the placebo. AEs of at least grade 3 occurred in 26% of patients in the 1500-mg group, 23% in the 900-mg group, and 26% in the placebo group, according to the study.

Overall, voxelotor significantly increased hemoglobin levels and reduced markers of hemolysis, meeting the primary endpoint of the trial.

With the Priority Review designation, the agency has assigned a Prescription Drug User Fee Act target action date of February 26, 2020.

Reference

GBT Announces US Food and Drug Administration Acceptance of New Drug Application and Priority Review for Voxelotor for the Treatment of Sickle Cell Disease [news release]. Global Blood Therapeutics. https://ir.gbt.com/news-releases/news-release-details/gbt-announces-us-food-and-drug-administration-acceptance-new. Accessed September 5, 2019.