The purpose of this study is to evaluate the long-term safety of eculizumab in patients with transfusion dependent hemolytic PNH.

An open-label extension study to evaluate long-term safety of eculizumab in PNH patients who had completed the TRIUMPH (C04-001), SHEPHERD (C04-002), and X03-001 studies.

Inclusion Criteria:

• Patients who have fully completed the TRIUMPH, SHEPHERD, or X03-001 studies
• TRIUMPH patients who have discontinued receiving investigational drug prior to the last visit of the study due to lack of efficacy or exacerbation of symptoms of PNH and have completed all monthly safety and efficacy procedures
• Patient must be willing and able to give written informed consent
• Patient must avoid conception during the trial

Exclusion Criteria:

• Patients who have terminated early from the SHEPHERD or X03-001 studies
• Patients who have terminated early from the TRIUMPH study due to an adverse event
• Female who is pregnant, breast feeding, or intending to conceive during the course of the study
• Any condition that could increase the patient's risk by participating in the study or could confound the outcome of the study