Samsung Bioepis presented compelling long-term safety data for EPYSQLI™ (eculizumab; SB12), its biosimilar to Soliris, demonstrating sustained safety in paroxysmal nocturnal hemoglobinuria (PNH) patients at the European Hematology Association (EHA) Congress 2025 in Milan, Italy. The extended follow-up study reinforces the biosimilar's safety profile over treatment periods extending up to 158 weeks.
Extended Safety Analysis Shows Consistent Outcomes
The comprehensive safety analysis evaluated 46 patients from the original Phase 3 study who continued into the extended treatment (ET) period, spanning from 52 weeks to up to 158 weeks. During the extended treatment phase, seven patients (15.2%) experienced a total of 14 serious adverse events (SAEs), with no fatal cases reported. Notably, all patients fully recovered without permanently discontinuing treatment.
The exposure-adjusted event rate (EAER) demonstrated remarkable consistency between the initial 52-week period and the extended treatment period, with rates of 0.13 and 0.17, respectively. Statistical analysis revealed no significant difference between these periods (p-value = 0.76), indicating stable safety outcomes over extended treatment duration.
Dosing and Administration Protocol
Throughout the study, patients received a standardized maintenance dose of 900 mg EPYSQLI administered every two weeks. This dosing regimen aligns with the approved therapeutic protocol for the biosimilar, which must be administered by healthcare professionals under physician supervision experienced in managing hematological disorders.
Regulatory Approval and Clinical Applications
EPYSQLI received European Commission approval for PNH treatment in May 2023 and for atypical hemolytic uremic syndrome (aHUS) in March 2024. The biosimilar has also secured approval from the U.S. Food and Drug Administration and Korea's Ministry of Food and Drug Safety. In the European Union, EPYSQLI is indicated for both adults and children with PNH and aHUS, though it is not approved for generalized myasthenia gravis or neuromyelitis optica spectrum disorder.
Safety Monitoring Requirements
The European Union Summary of Product Characteristics outlines critical safety considerations for EPYSQLI treatment. Due to eculizumab's mechanism of action, patients face increased susceptibility to meningococcal infections, requiring vaccination at least two weeks prior to treatment initiation. Patients must receive vaccines against serogroups A, C, Y, and W 135, with serogroup B vaccination also recommended where available.
For PNH patients, ongoing monitoring includes assessment of intravascular hemolysis signs and serum lactate dehydrogenase levels, with potential dose adjustments within the recommended 14±2 day maintenance schedule. The most common adverse reaction observed in clinical trials was headache, typically occurring during initial dosing phases, while meningococcal infection represents the most serious potential adverse reaction.
Clinical Significance for Biosimilar Development
The long-term safety data presented by Samsung Bioepis supports the sustained therapeutic equivalence of EPYSQLI to its reference product. The absence of newly identified safety signals throughout the extended treatment period, combined with complete resolution of all serious adverse events, provides clinicians with confidence in the biosimilar's long-term tolerability profile.
Samsung Bioepis, established in 2012, continues advancing its biosimilar pipeline across multiple therapeutic areas including immunology, oncology, ophthalmology, hematology, nephrology, and endocrinology. The company's commitment to accessible healthcare through biosimilar development addresses critical treatment needs in rare hematological conditions like PNH.
