Agios Pharmaceuticals (AGIO) stock was downgraded at Leerink Partners on Pfizer's (PFE) recent decision to withdraw sickle cell disease drug, Oxbryta. Read more here.

The U.S. Food and Drug Administration on Thursday alerted patients and healthcare professionals about the withdrawal of Pfizer's sickle cell disease treatment Oxbryta. Pfizer said late on Wednesday it was pulling the drug from all markets due to risk of a painful complication and death.

European regulators on Thursday also said that patients in the trials had higher rates of the pain crises that are hallmarks of sickle cell disease once they started on Oxbryta, also called voxelotor,