U.S. drugmaker Pfizer said on Wednesday it was withdrawing its sickle cell disease treatment Oxbryta from all markets where it is approved, citing risks of a painful complication and deaths.

Pfizer’s abrupt withdrawal of Oxbryta, a drug for sickle cell disease, has sent shockwaves through the medical community.

The company said it was withdrawing Oxbryta, a daily pill for patients with the disease, a serious, lifelong condition.

The healthcare company said clinical data indicates the overall benefit of Oxbryta no longer outweighs the risk in the approved sickle cell patient population.

Pfizer is withdrawing all of its sickle cell disease drug, Oxbryta, worldwide because of safety concerns. Pfizer ( PFE) shares declined Thursday after the drug maker recalled all lots of its sickle cell disease medicine worldwide because of concerns it could lead to severe pain and possibly death in patients.

Pfizer's decision late on Wednesday to withdraw its sickle cell disease treatment due to the risk of death could help speed up trials of new experimental rivals, Wall Street analysts said.

Pfizer Inc. said late Wednesday it was withdrawing a sickle-cell drug from markets worldwide and discontinuing clinical trials of the treatment after it investigates data suggesting a potential link to sickle-cell complications and “fatal events.”

Pfizer’s decision Wednesday to pull its sickle cell pill off the market because of safety concerns shocked advocates and doctors, leaving many searching for answers and scrambling for ways to notify their patients about a drug that has long divided the community.

The withdrawal comes as trial results indicate safety concerns with the drug, Oxbryta, which was first approved in the U.S. in 2019.