Alexion Pharmaceuticals says it has submitted a Biologics License Application in the USA asking for approval of its lead product candidate, Soliris (eculizumab), in the treatment of patients with paroxysmal nocturnal hemoglobinuria.

PNH is a rare, life-threatening form of hemolytic anemia, in which the body's complement system targets and destroys red blood cells. The company estimates that between 8,000 and 10,000 people in North America and Western Europe have the disease.

The BLA submission is based on data from the Phase III TRIUMPH trial, details of which were published recently in the New England Journal of Medicine. Patients treated with Soliris in the study did not require blood transfusions, unlike those in the placebo group who needed an average of 10 during the programme.

In addition, 49% of the drug-treated group achieved stable haemoglobin levels, with none of the subjects in the placebo arm meeting this objective.

Alexion added that it has requested a priority review for the BLA and hopes to file for approval of Soliris in Europe by the end of the year.

Analysts said eculizumab has a peak sales potential of around $150 million a year at its peak.