Coversin in Paroxysmal Nocturnal Haemoglobinuria (PNH)

Patients enrolled in this protocol will initially be treated with an ablating dose of Coversin and daily repeat maintenance doses calculated according to body weight, the ablating dose to be 0.57mg/kg. Thereafter the daily repeat dose will be titrated according to clinical response and complement inhibition determined by CH50 ELISA. The initial repeat dose will be 25% of the ablating dose and this will be adjusted up or down if necessary once steady state is reached (5 days).