Patients with sickle cell disease have one less treatment option after Pfizer announced that it will voluntarily withdraw Oxbryta® (voxelotor) from the global market due to safety concerns.
The safety concerns were seen in a clinical trial where patients with sickle cell disease were randomly assigned to Oxbryta or a placebo.
The group of patients on Oxbryta had more deaths and reports of a severely painful complication called vaso-occlusive crisis (also called a “sickle cell crisis”) compared to the group of patients on a placebo.
Oxbryta was also linked to higher rates of vaso-occlusive crisis in two real-world registry studies, according to Pfizer, which led the company to conclude that the risk of side effects outweighs any benefit.
Pfizer said, “The data suggest an imbalance in vaso-occlusive crises and fatal events which require further assessment. Pfizer’s decision is based on the totality of clinical data that now indicates the overall benefit of OXBRYTA no longer outweighs the risk.”
The FDA issued a Safety Communication asking doctors to stop prescribing Oxbryta. Patients should talk to their health care professional about stopping Oxbryta and starting another treatment.
There are several FDA-approved medications for sickle cell disease, including hydroxyurea, L-glutamine, and crizanlizumab‑tmca.
The FDA said it will conduct its own safety review of Oxbryta, including data from studies and adverse event reports that were submitted to the FDA, and “communicate any additional findings, if necessary.”