EU Confirms Oxbryta Risk of Sickle Cell Disease Complications, Death Outweigh Benefits

Review by European regulatory authorities found four times as many children died after taking Oxbryta than those given a placebo.

European Union drug regulators report they will keep the sickle cell disease treatment Oxbryta off the market, due to concerns over an increased risk of death from the very condition the medication is supposed to treat.

Originally introduced by Global Blood Therapeutics in 2019, Oxbryta (voxelotor) was promoted as the first medication to address the root causes of sickle cell disease. The drug’s designers claimed it would improve hemoglobin levels in the body, helping the blood cells retain more oxygen and prevent vaso-occlusive crises (VOC), which occur when the red blood cells block blood flow.

However, in September 2024, Pfizer issued an Oxbryta recall following a higher-than-expected number of VOC problems reported by users. As a result, the manufacturer now faces a number of Oxbryta lawsuits, alleging the drug worsened their condition and left them with severe, sometimes fatal, injuries that could have been prevented.

Following the recall announcement, the European Medicines Agency temporarily suspended use of Oxbryta to assess its risks. In a press release issued earlier this month, the EMA’s Committee for Medicinal Products for Human Use (CHMP) announced it has concluded its assessment and determined that the benefits do not outweigh the Oxbryta risks of causing sickle cell disease complications and death among users.

In its assessment, the CHMP looked at the effects of Oxbryta on children with sickle cell disease at higher risk of a stroke, finding that eight children taking the drug died, compared to only two among those given a placebo.

“Although the final analysis of the registry studies did not confirm an increase in sudden pain episodes with Oxbryta, the recent clinical trials did show more sudden pain episodes and deaths. These results are inconsistent with those of the earlier main clinical trial that supported Oxbryta’s authorisation, which had not shown a difference between treatment groups.”

– European Medicines Agency

The CHMP review found that the mechanism of action increasing Oxbryta’s health risks remained unclear, and could not find a way to reduce those risks. The committee determined that the suspension of Oxbryta should remain in place and continue to be unavailable for healthcare professionals or patients in the EU.

The committee’s opinion will be sent to the European Commission, which will issue a final ruling affecting the drug’s use in all EU member states.

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