Advancements in complement inhibition for PNH and primary complement-mediated thrombotic microangiopathy

Area of Science:

• Hematology
• Immunology
• Pharmacology

Background:

• Paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS) are complement-mediated hematologic disorders causing hemolysis and severe complications.
• While C5 inhibitors like eculizumab have improved management, breakthrough hemolysis persists in some patients with PNH.

Purpose of the Study:

• To review recent advances in complement-targeted therapies for PNH and atypical hemolytic uremic syndrome (aHUS).
• To highlight the efficacy and safety data of novel agents for PNH and current data for aHUS.

Main Methods:

• Review of recent randomized trials and clinical data for novel complement inhibitors.
• Focus on therapies targeting upstream complement pathways, including C3, Factor B, and Factor D inhibitors, and novel anti-C5 antibodies.

Main Results:

• Several novel agents (pegcetacoplan, iptacopan, danicopan, crovalimab) are approved for PNH, showing efficacy in patients with breakthrough hemolysis.
• Current data for aHUS primarily supports approved terminal complement inhibitors (eculizumab, ravulizumab), with ongoing research for novel agents.

Conclusions:

• Novel complement inhibitors represent significant advancements in treating PNH and hold potential for aHUS.
• Further research is essential to determine the long-term efficacy and safety of these emerging therapies for PNH and aHUS patients.