The European Medicines Agency (EMA) is reviewing an application from Global Blood Therapeutics (GBT) that seeks full marketing approval for the oral therapy Oxbryta (voxelotor) for people with sickle cell disease (SCD), ages 12 and up.
Oxbryta would be the first treatment targeting the root cause of SCD, hemolytic anemia, to be approved in the EU.
“We look forward to working with the EMA to meet our goal of bringing the first treatment for hemolytic anemia in sickle cell disease to European patients as soon as possible,” Ted W. Love, MD, president and CEO of GBT, said in a press release.
Love noted that, currently, there are no medications approved in Europe for altering the course of SCD.
SCD is characterized by abnormally shaped red blood cells — the “sickle cells” that give the disease its name. Within the body, these abnormal cells are destroyed by normal quality-control mechanisms.
Hemolytic anemia occurs when red blood cells are being destroyed more quickly than they are made. Since red blood cells are responsible for transporting oxygen through the bloodstream, this impedes oxygen delivery to the body’s tissues.
Sickle cells form because of an abnormal form of hemoglobin (the molecule used to transport oxygen) that tends to form clumps, resulting in the cells becoming deformed. Oxbryta increases hemoglobin’s affinity for oxygen, which helps to prevent the formation of these clumps. This, in turn, helps to limit red blood cell sickling and, consequently, hemolytic anemia.
Oxbryta is approved in the U.S. as a treatment for SCD in individuals age 12 and older. GBT also has announced plans to seek an expanded approval in the U.S., which would cover children with SCD as young as age 4.
In Europe, Oxbryta has been included in the EMA’s priority medicines (PRIME) program, and the European Commission has granted it orphan medicinal product designation for the treatment of SCD.
GBT’s application to the EMA is based on data from two clinical trials. The HOPE Phase 3 trial (NCT03036813), completed in 2019, tested the medication in people with SCD, ages 12 and older. The ongoing HOPE-KIDS 1 Phase 2 trial (NCT02850406) is evaluating Oxbryta in children with SCD between the ages of 9 months and 17 years.
Results from the HOPE trial — in which daily treatment with Oxbryta was compared to a placebo for six months — demonstrated robust and sustained improvements in the amount of healthy, circulating red blood cells in teenagers and adults. The treatment also reduced markers of hemolysis, or red blood cell destruction.
Further data from HOPE, showing the effects of the treatment in patients for up to 72 weeks (just under one and half years), were presented at the 2020 annual meeting of the American Society of Hematology. That update showed generally consistent long-term results.
Specifically, at 72 weeks, 88.9% of participants on Oxbryta at a dosage of 1,500 mg (the dosage approved in the U.S.) had an increase in hemoglobin levels of at least 1 g/dL, as compared with 25% of those given a placebo.
Similarly, more participants on Oxbryta than a placebo had an increase of at least 2 g/dL (58.9% vs. 3.3%) and of at least 3 g/dL (20% vs. 0%). Hemolysis markers also were significantly reduced at this time point.
Oxbryta was generally well-tolerated among HOPE participants. Side effects that were more common with this medication than a placebo at six months included headache, diarrhea, abdominal pain, nausea, fatigue, rash, and fever. Serious side effects occurred with similar frequencies in individuals given Oxbryta and those given a placebo for up to 72 weeks, the new data showed.
HOPE-KIDS 1 is still ongoing, with preliminary findings that generally have been consistent with the results seen in SCD adults.
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