KP104

KP104 is a first-in-class bifunctional biologic drug developed by Kira Pharmaceuticals. It is a recombinant fusion protein that combines a humanized anti-C5 monoclonal antibody with the functional domain of complement regulator factor H. This unique structure enables KP104 to simultaneously inhibit both the upstream alternative pathway (via Factor H) and the downstream terminal pathway (via C5) of the complement system. By targeting these two key points, KP104 offers a synergistic approach to treating complement-mediated diseases where single-target inhibitors are insufficient. The drug has been engineered for extended half-life and potency, with formulations suitable for both intravenous and subcutaneous administration. KP104 is primarily being developed as a monotherapy for paroxysmal nocturnal hemoglobinuria (PNH), where it has demonstrated robust efficacy in controlling both intravascular and extravascular hemolysis in Phase 2 clinical trials. Additionally, it is under investigation for other indications such as IgA nephropathy (IgAN), C3 glomerulopathy (C3G), and thrombotic microangiopathies secondary to systemic lupus erythematosus (SLE-TMA). The US FDA has granted Orphan Drug Designation to KP104 for PNH[1][4][5][6][7][8].