Alexion is gearing up to file its experimental therapy for paroxysmal nocturnal hemoglobinuria (PNH) with regulators on both sides of the Altantic following the success of a late-stage clinical trial.

PNH is a chronic, progressive, debilitating, and potentially life-threatening ultra-rare blood disorder that can affect men and women without warning, with an average age of onset in the early 30s.

In patients with PNH, chronic, uncontrolled activation of the complement system, a component of the body’s immune system, causes the destruction of red blood cells, which can lead to progressive anaemia, fatigue, dark urine, and shortness of breath.

In the most severe cases, the condition can cause the formation of blood clots, potentially damaging vital organs and causing premature death.

Data from a pivotal Phase III study of Alexion’s ALXN1210 showed that the long-acting C5 complement inhibitor was non-inferior to Soliris (eculizumab) in complement inhibitor treatment-naïve patients with PNH, based on the co-primary endpoints of transfusion avoidance and normalisation of lactate dehydrogenase (LDH) levels.

The study also showed non-inferiority on all key secondary endpoints, while there was no notable difference in safety profiles, the firm said.

“We are very pleased with these positive data for ALXN1210 in the first and only head-to-head study versus Soliris, and the results reinforce our ambition to establish ALXN1210 as the new standard of care for patients with PNH,” said John Orloff, head of R&D at Alexion.

“The data are also consistent with our hypothesis that immediate, complete, and sustained C5 inhibition is critical for patients with this potentially life-threatening disease,” he added.

The firm said it would be filing the drug with regulators in the US, EU and Japan later this year.