Voxelotor (Oxbryta) gained approval for sickle cell disease in adults and children as young as 12 years old, the .
The drug is the first in a new class that helps keep sickle hemoglobin from creating a polymer that, when deoxygenated, deforms red blood cells into the characteristic sickle shape that causes tissue damage and pain.
"With Oxbryta, sickle cells are less likely to bind together and form the sickle shape, which can cause low hemoglobin levels due to red blood cell destruction," Richard Pazdur, MD, acting director of the Office of Oncologic Diseases in the FDA's Center for Drug Evaluation and Research, said in a press release. "This therapy provides a new treatment option for patients with this serious and life-threatening condition."
The approval was based on the , in which normal hemoglobin levels rose more than 1.0 g/dL from baseline to week 24 for 51% of voxelotor-treated patients compared with 7% of those on placebo (P<0.001).
While that degree of improvement is associated with significantly decreased rates of multiorgan failure and death in natural history studies, and considered a "response," the FDA cautioned that further trials are needed to verify the drug's clinical benefit.
Voxelotor was approved on the , "based on a result that is reasonably likely to predict a clinical benefit to patients."
"A 1-g increase in hemoglobin is nice, but if it doesn't make the patient overall better in ways that are important to us then I don't really think it's a therapy that's going to have a major role in the treatment of sickle cell patients in the future," Andrew Eisenberger, MD, of NewYork-Presbyterian Hospital/Columbia University Medical Center in New York City, told MedPage Today at the time of the HOPE trial publication.
Red-cell transfusions were no less frequent with the drug, and acute vaso-occlusive crises were only slightly less common than with placebo.
The drug is taken orally once a day. Drugmaker it expected voxelotor to be available on the market within 2 weeks.
Common side effects are headache, diarrhea, abdominal pain, nausea, fatigue, rash, and fever.