This study is a retrospective non-interventional study, and the main objective of this study is to identify the impact of eculizumab treatment and the improvement of complications before and after eculizumab treatment, and to evaluate the safety during the treatment and the clinical unmet needs during the treatment in PNH patients in real-world.

Inclusion Criteria:

• Patients with PNH aged 18 years or older who started eculizumab treatment in accordance with drug label between 2012 and January 31st, 2020. (However, patients who have received eculizumab as part of a clinical trial or an expanded access program/compassionate use program prior to 2012 are also eligible.)
• Patients who are vaccinated against Neisseria meningitidis at least 2 weeks prior to starting eculizumab treatment. Patients who have been treated with appropriate prophylactic antibiotic therapy for 2 weeks after vaccination if they received eculizumab within 2 weeks after the vaccination.

Exclusion Criteria:

• Pediatric patients with PNH aged under 18 years
• Patients with hypersensitivity to the active ingredients of eculizumab, murine protein, or other components
• Patients with untreated severe meningococcal (Neisseria meningitidis) infection
• Patients who received other complement inhibitors for PNH before or during eculizumab treatment

Patients with PNH aged 18 years or older who started receiving eculizumab treatment accordance with the drug label until January 31, 2020 will be enrolled in this study.