Sickle cell disease is a lifelong, inherited blood disorder in which red blood cells are abnormally shaped (in a crescent, or “sickle” shape), which restricts the flow in blood vessels and limits oxygen delivery to the body’s tissues, leading to severe pain and organ damage. It is also characterized by severe and chronic inflammation that worsens vaso-occlusive crises during which patients experience episodes of extreme pain and organ damage. Nonclinical studies have demonstrated that Oxbryta inhibits red blood cell sickling, improves red blood cell deformability (ability of a red blood cell to change shape) and improves the blood’s ability to flow.
“Oxbryta is an inhibitor of deoxygenated sickle hemoglobin polymerization, which is the central abnormality in sickle cell disease,” said Richard Pazdur, M.D., director of the FDA’s Oncology Center of Excellence and acting director of the Office of Oncologic Diseases in the FDA’s Center for Drug Evaluation and Research. “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. This therapy provides a new treatment option for patients with this serious and life-threatening condition.”
Oxbryta’s approval was based on the results of a clinical trial with 274 patients with sickle cell disease. In the study, 90 patients received 1500 mg of Oxbryta, 92 patients received 900 mg of Oxbryta and 92 patients received a placebo. Effectiveness was based on an increase in hemoglobin response rate in patients who received 1500 mg of Oxbryta, which was 51.1% for these patients compared to 6.5% in the placebo group.
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