Real-world management of patients with paroxysmal nocturnal hemoglobinuria in Russia: outcomes of the multicenter retrospective RADAR-PNH study

Background. Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening disease characterized by intravascular hemolysis, thrombosis, and bone marrow failure. The introduction of anti-C5 therapy (eculizumab, ravulizumab) has significantly improved patient outcomes; however, suboptimal hematological response, breakthrough hemolysis, and inadequate disease monitoring persist in real-world clinical practice. Data on the real-world management of PNH patients in the Russian Federation are limited, justifying the need for the present study. Aim. To evaluate the clinical and demographic characteristics, the rate and quality of hematological response, the frequency of laboratory monitoring, and the disease course features in PNH patients receiving or not receiving complement C5 inhibitors (anti-C5 therapy) in real-world clinical practice in the Russian Federation. Materials and methods. A retrospective, non-interventional study (RADAR-PNH) was conducted and included 145 adult patients with a confirmed diagnosis of PNH. The primary analysis assessed hematological response and the frequency of key disease parameters monitoring during the 12 months following anti-C5 therapy initiation (n = 128). Results. An optimal hematological response to anti-C5 therapy was achieved in 75 (58.6 %) of patients, including a complete response in 31 (24.2 %) and a good response in 44 (34.4 %). A suboptimal response persisted in 53 (41.4 %) of patients, including a minor response in 21 (16.4 %). Only 32 (25 %) of patients on anti-C5 therapy underwent complete regular laboratory monitoring. During the entire observation period, 43 (33.9 %) patients required red blood cell transfusions. Breakthrough intravascular hemolysis was reported in 30 (23.4 %) of patients. Five (3.9 %) patients developed thrombosis while receiving C5 inhibitor therapy. Conclusion. The obtained data indicate a substantial proportion of patients with an incomplete hematological response, inadequate laboratory monitoring, and a persistent risk of breakthrough hemolysis and thrombosis even during targeted therapy. This study may provide a basis for systemic improvements in the diagnosis, follow-up, and treatment of PNH aimed at enhancing the quality of life and prognosis in this patient population.