Oxbryta Recall Announced After Studies Show Sickle Cell Drug’s Risks Outweigh Benefits

Pfizer has issued a global recall for Oxbryta, a recently approved drug for treatment of sickle cell disease, indicating that the risk of life-threatening side effects outweighs potential benefits provided by the medication.

The pharmaceutical company announced the Oxbryta recall in a press release issued September 25, indicating that it is also discontinuing clinical trials for the drug, amid reports of users experiencing painful sickle cell complications and fatalities.

Oxbryta (voxelotor) was approved for the treatment of sickle cell disease by the U.S. Food and Drug Administration (FDA) in 2019, through an accelerated approval program. Pfizer acquired the drug when it bought Global Blood Therapeutics in 2022, and the European Commission provided market authorization for Oxbryta that same year.

Sickle Cell Treatment

Sickle cell disease, also called sickle cell anemia, is a lifelong inherited blood disorder that affects the protein in the blood and causes the blood cells to break down and die from a lack of oxygen. It is a serious condition, which can cause blood flow blockage, infections, pain and fatigue.

There is no cure for sickle cell disease, and it is difficult to manage, since there are limited treatment options. Oxbryta was the first drug approved to treat the root cause of sickle cell disease, by improving hemoglobin levels in the body, helping the blood cells hold on to more oxygen.

In the press release, Pfizer said there was an imbalance in vaso-occlusive crises and fatal events among those using Oxbryta. As a result, the company concluded that the risks of Oxbryta side effects appear to outweigh benefits the medication may provide.

Vaso-occlusive events occur when the red blood cells block blood flow, and the tissues become deprived of oxygen. This can cause an inflammatory response, which can lead to symptoms like pain in the chest, back and limbs, as well as fever. Patients often have to be hospitalized and can suffer kidney failure and stroke. Additionally, many patients can suffer death following a vaso-occlusive event.

According to an alert (PDF) issued by the European Medicines Agency (EMA) in late July, there were at least eight reported deaths among Oxbryta users in one clinical trial involving 236 people. The results caused the EMA to launch a safety review of the drug, ultimately leading Pfizer to recall Oxbryta this week.

“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, Chief Medical Officer and Head of Worldwide Medical and Safety at Pfizer, said in the press release. “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.”

Pfizer notified regulatory agencies around the world about the global market withdrawal and the findings of the clinical trials. The company said it will continue to review the available data on the drug and update regulators.

Patients are urged to contact their doctor about using alternative treatments and stopping Oxbryta. Patients and doctors can also contact Pfizer with questions at 1-800-438-1985. Any side effects or symptoms experienced while taking Oxbryta should be reported to the FDA’s MedWatch Adverse Event Reporting program.