Pfizer withdraws sickle cell disease treatment on risk of complication, death

US drugmaker Pfizer said on Wednesday (Sept 25) it is withdrawing its sickle cell disease treatment Oxbryta from all markets where it is approved, citing risks of a painful complication and deaths.

Pfizer bought Oxbryta, also known as voxelotor, as part of its US$5.4 billion (S$6.95 billion) buyout of Global Blood Therapeutics in 2022.

It reported US$328 million in revenues from the therapy for the full year 2023.

Pfizer is also discontinuing all studies and access programs related to the treatment based on the available clinical data, which shows that the benefit of the drug no longer outweighs the risks associated with its use, it said.

The company added that the data shows an imbalance in vaso-occlusive crises, a complication of the disease and 'fatal events' that requires further assessment.

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Vaso-occlusive crisis in patients with the disease occurs when blood flow gets blocked, depriving a tissue of oxygen and triggering an inflammatory response.

The withdrawal comes ahead of an 'extraordinary meeting' on Thursday of European health regulator's Committee for Medicinal Products for Human Use to review Pfizer's drug.

In a study of 236 people, there were eight deaths in patients taking Oxbryta and two deaths in the placebo arm.

Pfizer said it will further review the available data and had notified regulatory authorities about its findings. It said it had advised patients to contact their physicians to discuss alternative treatment.

The US Food and Drug Administration granted an accelerated approval to the therapy in 2019. It is also approved in Europe, UK and United Arab Emirates.

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