A recombinant, chimeric human fusion protein consisting of the iC3b/C3d-binding region of human complement receptor type 2 (CR2/CD21) linked to the alternative complement pathway (ACP) inhibitory domain of human factor H (fH) (CR2-fH), with potential complement system inhibiting activity. Via its C3 binding domain, TT30 selectively binds to complement-activated cell surfaces and via its fH binding domain regulates ACP activity. This suppresses excessive complement activity and may result in an inhibition of ACP-mediated hemolysis of paroxysmal nocturnal hemoglobinuria (PNH) red blood cells (RBCs) as well as preventing ACP-induced tissue damage. Factor H is a key regulator in the activation of ACP. Check for active clinical trials using this agent.