The European Medicines Agency (EMA) is set to discuss Pfizer's Oxbryta (voxelotor) following reports of patient deaths in two clinical trials. The meeting, scheduled for Thursday, will address concerns raised after a higher number of deaths were observed in patients treated with Oxbryta in studies focused on stroke risk and leg ulcers.
The EMA initiated a review of Oxbryta in July after a clinical trial involving patients at high risk of stroke revealed a higher incidence of deaths in the treatment arm compared to the placebo group. Specifically, the study, which enrolled 236 participants across multiple countries including Egypt, Ghana, Kenya, Nigeria, Oman, Saudi Arabia, the US, and the UK, reported eight deaths in the Oxbryta group versus two in the placebo group as of July 29.
Another trial, focusing on leg ulcers and recruiting 88 patients from Brazil, Kenya, and Nigeria, also reported a higher-than-anticipated number of deaths during the open-label phase. As of July 29, eight deaths had been reported in this study, according to the EMA.
In response to these findings, treatment with Oxbryta was halted in both studies. At the time of the initial announcement, regulators stated that there was no direct evidence linking Oxbryta to the deaths, suggesting that some fatalities may have resulted from infections such as malaria.
Pfizer acquired Oxbryta as part of its $5.4 billion acquisition of Global Blood Therapeutics (GBT) in 2022. The company has declined to comment ahead of the EMA meeting. The EMA's review aims to determine whether there is a causal relationship between Oxbryta and the reported deaths, and to assess the overall benefit-risk profile of the drug for patients with sickle cell disease.
