The indication had previously been for patients 12 years old and up, the FDA said in an announcement.
Voxelotor (Oxbryta) was originally approved for sickle cell disease in November 2019 and was described as the first drug that directly inhibits sickle hemoglobin polymerization, the root cause of the disease. It binds and stabilizes hemoglobin to prevent red blood cells from sickling and being destroyed.
Approval for the new indication of use in children down to age 4 was based on data from a phase 2 trial that involved 45 children aged 4-11 years; the results show that 36% had an increase in hemoglobin greater than 1 g/dL by week 24, the FDA said.
“Complications of [sickle cell disease] that can cause irreversible organ damage are known to begin in the first few years of life, which is why earlier intervention is critical,” commented Ted Love, MD, president and CEO of Global Blood Therapeutics, the manufacturer, in a press release.
The company is studying voxelotor in children as young as 9 months old.
The agent was granted an accelerated approval by the FDA, so continued approval depends on additional data to confirm that increases in hemoglobin have clinical benefit.
With the new approvals, voxelotor is now available in 500-mg tablets and the 300-mg tablets for oral suspension. Dosing for ages 12 years and up is 1,500 mg once daily. Dosing for children 4 to up to 12 years old is weight based.
The most common side effects are headache, vomiting, diarrhea, abdominal pain, nausea, rash, and fever.
A version of this article first appeared on Medscape.com.