GBT to Request That Oxbryta Treat Children Starting at Age 4

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Global Blood Therapeutics (GBT) will ask the U.S. Food and Drug Administration (FDA) to allow children with sickle cell disease (SCD), ages 4 to 11, to also be treated with Oxbryta (voxelotor).

The company announced plans to file an application requesting extended approval after a Type B meeting with FDA officials.

“We are pleased to have agreed with the FDA on a potential path forward to expand the use of Oxbryta in younger children, and we look forward to submitting a New Drug Application by the middle of next year,” Ted W. Love, MD, president and CEO of GBT, said in a press release.

SCD is caused by mutations in the HBB gene, which codes for a component of the oxygen-carrying protein hemoglobin. As a result, hemoglobin molecules stick together, which makes red blood cells turn rigid to slow or prevent blood flow.

Oxbryta is approved by the FDA to treat SCD in individuals ages 12 and older. The oral medication works by binding to hemoglobin, increasing the protein’s affinity for oxygen, and preventing red blood cells from becoming deformed. According to GBT, Oxbryta is the first and only therapy that treats SCD at its root cause.

“By mitigating red blood cell sickling and destruction early in life, we hope to positively impact the course of the disease,” Love said.

The planned application will be supported by data from the ongoing Phase 2a clinical trial called HOPE KIDS-1 (NCT02850406), sponsored by GBT. This study is evaluating the safety and early efficacy of Oxbryta in children and adolescents, as well as the medication’s pharmacokinetics (how it moves through and is processed by the body).

HOPE KIDS-1 is enrolling up to 155 patients between the ages of 9 months and 17 years. Recruitment is ongoing at multiple sites in the U.S, U.K., and Lebanon. More information, including contacts, can be found here.

Data from the Phase 3 HOPE trial (NCT03036813), which supported the therapy’s accelerated approval in November 2019, found that Oxbryta’s use led to robust and sustained improvements in the amount of healthy, circulating red blood cells in teenagers and adults.

GBT is also running a trial testing Oxbryta in children ages 2 to 15, called HOPE KIDS-2 (NCT04218084). This Phase 3 trial was requested by the FDA as a confirmatory study to support Oxbryta’s accelerated approval, and its primary goal is to assess whether the therapy decreases stroke risk after 24 weeks of treatment.

Patients will either receive daily Oxbryta tablets at 1500 mg — its approved dose — or a placebo for up to 96 weeks; use of hydroxyurea, a standard treatment, is allowed.

HOPE Kids-2 will enroll about 224 children. It is currently recruiting at locations in the U.S., with plans to also enroll at sites in Egypt, Ghana, Italy, Kenya, Oman, Saudi Arabia, and the U.K. Additional information can be found here.