Ĭlinical PNH arises from expansion of the PNH stem cell in the bone marrow often following an immunological ‘insult’, such as preceding aplastic anaemia, although this may be transient and silent. Prior to the availability of the monoclonal antibody eculizumab, thrombosis accounted for 22–67% of deaths in the PNH case series, with 29–44% of patients with PNH having had at least one thrombosis. Thrombosis risk has been known about for over 30 years, with a significant associated mortality risk. Patients with PNH prior to the availability of eculizumab had a median survival of between 10 and 22 years.
Paroxysmal nocturnal haemoglobinuria (PNH), an ultra-orphan disease with a prevalence of 15.9 per million in Europe, is a life-threatening disorder, characterized by haemolysis, bone marrow failure and thrombosis.
