Alexion Pharmaceuticals Inc. priced its rare blood disorder drug Ultomiris at $6,404 per 30-milliliter vial as the U.S. Food and Drug Administration approved the drug almost two months ahead of schedule.

Ultomiris, formerly known as ALXN1210, is now approved to treat patients with paroxysmal nocturnal hemoglobinuria, or PNH, a chronic, progressive and debilitating blood disorder characterized by the destruction of red blood cells, blood clots and impaired bone marrow function. The drug prevents the rupturing of red blood cells in patients.

The approval is based on results from two late-stage studies of the drug. One phase-3 trial, called Switch, demonstrated that Ultomiris administered every eight weeks worked as well as a two-week regimen of the company's other medicine for the disorder called Soliris. In the other late-stage study, the drug was found to be as effective as Soliris and displayed a similar safety profile.

The U.S. FDA approval comes ahead of the Feb. 18, 2019, deadline set by the regulator for the expedited eight-month review of Alexion's application, which was submitted through a rare disease priority review voucher.

Richard Pazdur, director of the FDA's Oncology Center of Excellence, said Ultomiris will change the way patients with PNH are treated.

"Prior to this approval, the only approved therapy for PNH required treatment every two weeks, which can be burdensome for patients and their families," said Pazdur, who also serves as acting director of the Office of Hematology and Oncology Products at the FDA's Center for Drug Evaluation and Research. "Ultomiris uses a novel formulation so patients only need treatment every eight weeks, without compromising efficacy."

The therapy will allow patients to transition from bi-weekly drug infusions to just six or seven infusions a year.

Alexion Vice President and head of research and development John Orloff noted that the phase 3 trial data was reported less than a year ago. He said Ultomiris could become the new standard of care for PNH.

In a Dec. 21 regulatory document, Alexion said the price of $6,404 per vial represents a 10% discount from the current standard of care.

Alexion's Ultomiris is also under review in the EU and Japan.