Background Paroxysmal nocturnal haemoglobinuria (PNH) is a blood disorder characterised by intravascular haemolysis, due to the absence of glycophosphatidylinositol, a protein in red blood cells that prevents destruction by complement. Eculizumab is a recombinant humanised monoclonal antibody, used to avoid complement-induced haemolysis.

Purpose To compare the inclusion and exclusion criteria for treatment with eculizumab in four Autonomous Communities of Spain (Andalusia, the Canary Islands, Catalonia and the Basque Country). To evaluate the patients in our hospital by different criteria.

Materials and methods Review the protocols and compare with patients in treatment with eculizumab in our hospital.

Results There are important differences among the inclusion criteria: the value of lactate dehydrogenase (LDH) as an indicator of intravascular haemolysis must be higher than 1.5 times the upper limit of normal (ULN) in the Basque Country and the Canary Islands and more than 3 times in Andalusia and Catalonia. With regard to transfusions, in the Basque Country and the Canary Islands the patients are required to have received one blood transfusion because of haemolytic anaemia, whereas Andalucía requires at least 4 transfusions and Catalonia 8 in the previous year. In the exclusion criteria, Catalonia and Andalusia set marrow anaemia or myelodysplastic syndrome, however the Basque Country and the Canary Islands only exclude patients with marrow aplasia with platelet count <30 × 10⁹ and neutrophils <500/mm³. In our centre we have treated two patients who met the criteria in our community and in the Basque Country but who would not have been treated in Catalonia or Andalusia. In one case there was no marrow aplasia and the other one the LDH was not 3 times higher than ULN.

Conclusions Common national protocols are required for drugs for rare diseases whose clinical efficacy is questionable and variable.

Clinical assessment and treatment monitoring should be used to identify ineffective treatment, which should be discontinued.

No conflict of interest.