C5 inhibitor treatment (e.g., eculizumab and ravulizumab) greatly reduces the incidence of TEs in patients with PNH, but data on the characteristics of PNH patients experiencing TEs are limited.<h4>Methods</h4>This post-marketing surveillance sub-analysis evaluated the incidence of TEs in patients with PNH in Japan.<h4>Results</h4>During eculizumab treatment, 54 TEs occurred in 44/794 patients (5.5%), an incidence of 1.50/100 patient-years. This evidence concerns the gene C5 and paroxysmal nocturnal hemoglobinuria.