Paroxysmal nocturnal hemoglobinuria (PNH) is a nonmalignant clonal disorder resulting from somatic mutation in the PIG-A gene leading to a deficiency of the membrane-anchoring molecule glycosylphosphatidylinositol. The lack of expression of two glycosylphosphatidylinositol-anchored proteins involved in the regulation of the complement system renders PNH erythrocytes susceptible to complement-mediated lysis. Clinical manifestations include thromboembolic disease, chronic kidney injury, pulmonary hypertension, smooth muscle dysfunction, and chronic hemolysis. Until recently, treatment was mainly supportive with most patients suffering from significant morbidity and shortened survival compared to age-matched controls. The development of eculizumab, a humanized monoclonal antibody directed against the terminal complement protein C5, has resulted in dramatic improvements of survival and reduction in complications. In this paper, we review some special considerations pertaining to the use of eculizumab for PNH.

Intravenous iron therapy is a treatment option for iron deficient patients who are intolerant to oral iron or where oral iron is ineffective, but with possible adverse effects. Currently, prospective studies comparing different intravenous iron formulations are needed to determine safety and efficacy of these agents. We conducted a prospective, double-blind, randomized controlled trial (RCT) to assess the feasibility of a trial comparing the safety of high molecular weight intravenous iron dextran, Infufer®, with intravenous iron sucrose, Venofer®, in non-hemodialysis adult outpatients. Primary outcome was the occurrence of immediate severe drug reactions. We enrolled 143 patients in a one-year period. Overall, 45/143 (31.5 %) patients (20 iron dextran, 25 iron sucrose) developed 48 infusion reactions (14 immediate, 28 delayed, and 3 both). The risk of an immediate reaction was similar in both groups, 9/73 (12.3 %) iron dextran versus 8/70 (11.4 %) iron sucrose, RR = 0.93 (95 % CI; 0.38 to 2.27). The risk of a delayed reaction was significantly higher in the iron sucrose group 22/70 (31.4 %) versus the iron dextran group 9/73 (12.3 %), RR = 2.55 (95 % CI; 1.26 to 5.15; p = 0.0078). In this limited feasibility study, no major differences in immediate reactions were seen, but a significantly higher number of delayed reactions were seen in the iron sucrose group. Further, under our assumptions and design a full RCT to evaluate the safety of different intravenous iron preparations is not feasible. Future studies should consider modifying the clinical outcomes, utilize multiple centers, and consider other emerging parenteral iron formulations. (ClinicalTrials.gov NCT005936197 January 3, 2008).