Pfizer has voluntarily withdrawn its sickle cell disease treatment Oxbryta (voxelotor) from the market due to safety concerns.
The Food and Drug Administration (FDA) recommends clinicians stop prescribing the treatment and patients talk to their doctor about starting a different treatment.
“I am disappointed as many other providers, patients and families (are),” said Banu Aygun, M.D., FAAP, a lead author of the AAP clinical report Health Supervision for Children with Sickle Cell Disease and a member of the AAP Section on Hematology/Oncology. “And it is a reminder that we always need to be vigilant about new medications and treatments.”
Sickle cell disease is a disorder in which red blood cells form a C shape and become sticky and fragile. It can cause debilitating pain and organ damage and affects about 100,000 people in the U.S. Rates are disproportionately high in people of African descent in the U.S. About 20,000 people with sickle cell have severe disease.
Oxbryta increases hemoglobin’s affinity for oxygen and inhibits sickle hemoglobin polymerization. The FDA approved it under the accelerated approval pathway in 2019 for patients 12 years and older. In 2021, it granted accelerated approval down to age 4. Accelerated approval uses a surrogate endpoint to allow earlier approval of drugs that treat serious conditions and to fill an unmet medical need. Follow-up studies are required to verify the clinical benefits.
In the case of Oxbryta, those post-marketing clinical trials showed higher rates of vaso-occlusive crises (marked by severe pain) and deaths in patients with sickle cell compared to the placebo group, according to the FDA. Two real-world registry studies also found higher rates of vaso-occlusive crises in patients undergoing treatment with Oxbryta.
Pfizer said data indicate the benefits of the treatment no longer outweigh the risks, leading it to withdraw the treatment from the market and discontinue all active clinical trials.
“The safety and well-being of patients is of the utmost importance to Pfizer, and we believe this action is in the best interest of patients,” Aida Habtezion, M.D., M.Sc., FRCPC, AGAF, chief medical officer and head of worldwide medical and safety at Pfizer, said in a press release.
Pediatric primary care providers can find recommendations for comprehensive care of patients with sickle cell disease in the AAP clinical report.
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