Promising results from Eculizumab trials for patients with PNH Background Paroxysmal nocturnal haemoglobinuria (PNH) remains a complication seen in up to a half of patients with aplastic anaemia, especially after treatment with immune-suppressive therapy. This results from complement (an arm of the immune system) mediated destruction of the red blood cells. Encouraging discovery - Eculizumab Anti-complement therapy (Eculizumab) has revolutionised the treatment of PNH, offering freedom from blood transfusion and independence to a majority of these patients. However, this requires 2 weekly infusions of the drug. Longer derivatives of this drug, have been trialled in phase 1 and 2 studies, ALXN 1210-PNH-103 and 201 study, examining a treatment naïve group of patients with PNH. Preliminary evidence from these studies show that the effect at complement blockade was rapid and sustained. The drug was safely tolerated and did not result in any significant side effects resulting in discontinuation. Furthermore, efficacy was seen with an improvement in blood parameters as well as an improvement in the FACIT-fatigue score (patient reported fatigue scoring system). This holds promise, as results from this study have led to the initiation of phase 3 trials, so watch this space.