What is Oxbryta (voxelotor) for?

The Food and Drug Administration granted accelerated approval to Oxbryta (voxelotor) based on increase in hemoglobin among participants of the HOPE study, a randomized, double-blind, placebo-controlled, multicenter trial. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trial(s). Efficacy of Oxbryta (voxelotor) was evaluated in 274 patients with sickle cell disease. Participants were randomly assigned to receive a once-daily oral dose of 1,500 mg of voxelotor (N=90), 900 mg of voxelotor (N=92), or placebo (N=92). Patients were enrolled if they had from 1 to 10 vasoocclusive crisis (VOC) events within 12 months prior to enrollment and their baseline hemoglobin (Hb) were ≥5.5 to ≤10.5 g/dL. Patients on stable hydroxyurea doses for at least 90 days continued the drug throughout the trial. The primary endpoint was the percentage of participants who had a hemoglobin response, which was defined as an increase from baseline of more than 1.0 g per deciliter after 24 weeks of treatment, in patients treated with 1,500 mg of voxelotor versus placebo who showed >1g/dL increase in blood hemoglobin levels: 51.1% (46/90) of the patients receiving 1,500 mg of voxelotor, and 6.5% (6/92) of the patients receiving a placebo. Additional efficacy evaluation included change in Hb, percent change in indirect bilirubin and percent reticulocyte count from baseline to week 24. In the 1,500 mg voxelotor group, the mean change for Hb, indirect bilirubin, and percent reticulocyte count were 1.14 g/dL, ‑29.08%, and ‑19.93%, respectively. In the placebo group, the mean change from baseline to week 24 for Hb, indirect bilirubin, and percent reticulocyte count were −0.08 g/dL, −3.16%, and 4.54%, respectively. Most commonly reported adverse reactions (incidence >10%) to Oxbryta (voxelotor), with a difference between 1,500 mg voxelotor and placebo treatment arms of >3%, includeded headache (26% vs. 22%), diarrhea (20% vs. 10%), abdominal pain (19% vs. 13%), nausea (17% vs. 10%), fatigue (14% vs. 10%), rash (14% vs. 10%), and pyrexia (12% vs. 7%). The product information includes warnings for hypersensitivity and potential laboratory interference. Oxbryta (voxelotor) is contraindicated in patients with a history of serious drug hypersensitivity reaction to voxelotor or excipients, and voxelotor may interfere with measurement of Hb subtypes (HbA, HbS, and HbF) by high performance liquid chromatography. Further, Oxbryta (voxelotor) should only be used during pregnancy if the benefit of the drug outweighs the potential risk and breastfeeding is not recommended during treatment with Oxbryta (voxelotor), and for at least 2 weeks after the last dose. Please refer to the full prescribing information below for comprehensive information about the safety, efficacy and side effect/adverse reaction of Oxbryta (voxelotor) for the approved indication.