Pfizer Withdraws Sickle Cell Disease Treatment Due to Risk of Complications and Death, Reports Reuters

U.S. drugmaker Pfizer has announced the withdrawal of its sickle cell disease treatment, Oxbryta, from all markets where it is approved, due to concerns over the risks of painful complications and potential fatalities.

Pfizer acquired Oxbryta, also known as voxelotor, as part of its $5.4 billion acquisition of Global Blood Therapeutics in 2022. The therapy generated $328 million in revenues for Pfizer in 2023.

The company will also cease all studies and access programs associated with Oxbryta based on clinical data indicating that the benefits of the drug no longer outweigh the associated risks. Pfizer highlighted a concerning imbalance in vaso-occlusive crises and “fatal events” in the data, which necessitates further evaluation.

A vaso-occlusive crisis occurs when blood flow is obstructed, leading to oxygen deprivation in tissues and triggering inflammatory responses. The decision to withdraw Oxbryta comes as the European health regulator plans to hold an extraordinary meeting to review the drug.

In a study involving 236 participants, the trial reported eight deaths among those taking Oxbryta compared to two in the placebo group. Pfizer has indicated that it will continue to evaluate the available data and has informed regulatory authorities of its findings. Patients have been advised to consult with their healthcare providers regarding alternative treatments.

Oxbryta received accelerated approval from the U.S. Food and Drug Administration in 2019 and is also approved in Europe, the United Kingdom, and the United Arab Emirates.

Despite the withdrawal, Pfizer does not expect any impact on its financial outlook for the full year 2024. Oxbryta is indicated for an inherited blood disorder characterized by the sickling of red blood cells, which can lead to serious complications including strokes, organ damage, and early mortality.