EMA Suspends Sickle Cell Disease Medicine

The European Medicines Agency (EMA) announced on Sept. 26, 2024 that its Committee for Medicinal Products for Human Use (CHMP) has recommended that the marketing authorization for the sickle cell disease (SCD) drug, Oxbryta (voxelotor), be suspended. EMA stated in the press release that this is a precautionary measure as emerging safety data are reviewed (1). Sickle cell disease, according to EMA, is a genetic disease that produces an abnormal form of hemoglobin causing red blood cells to become rigid and sticky.

Data from two registry-based studies show that patients had a higher occurrence of vaso-occlusive crises (VOC) while being treated with Oxbryta. VOC are a common complication with sickle cell disease where patients experience episodes of acute pain that may lead to arthritis, kidney failure, or stroke.

The data were found during a benefit-versus-risks review of the medicine that was started in July 2024 because clinical trial data showed a higher number of deaths involved with use of Oxbryta. “In this context, the CHMP considered that, overall, these data raise serious concerns about the safety of Oxbryta; due to the increased uncertainties it therefore recommended that the authorization, marketing and supply of the medicine be suspended until all the available data have been assessed in the ongoing review,” the agency stated in a press release (1).

EMA is recommending that doctors not begin the use of Oxbryta with any new patients. Doctors should also stop treatment with those patients already using the medicine. Patients who have used Oxbryta should also be monitored for adverse events.

Pfizer, the marketing authorization holder of the medicine, is voluntarily withdrawing the medicine from areas in which is available and is discontinuing clinical trials and expanded access programs worldwide (2), stating in a press release that the benefits of the drug no longer outweigh the risks.

“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,” said Aida Habtezion, chief medical officer and head of Worldwide Medical and Safety at Pfizer, in the press release (2). “Our primary concern is for patients who suffer from SCD, which remains a very serious and difficult-to-treat disease with limited treatment options. We advise patients to contact their physicians to discuss alternative treatment while we continue to investigate the findings from our review of the data.”

Oxbryta is indicated for the treatment of hemolytic anemia in patients aged 12 years and older with sickle cell disease and works by increasing oxygen affinity in hemoglobin. “Oxbryta inhibits sickle hemoglobin polymerization and the resultant sickling and destruction of red blood cells leading to hemolysis and hemolytic anemia, which are primary pathologies faced by every single person living with SCD,” Pfizer stated in the press release (2).

References

1. EMA. EMA Recommends Suspension of Sickle Cell Disease Medicine Oxbryta. Press Release. Sept. 26, 2024.
2. Pfizer. Pfizer Voluntarily Withdraws All Lots of Sickle Cell Disease Treatment Oxbryta (voxelotor) From Worldwide Markets. Press Release. Sept. 25, 2024.