|Rontalizumab is a humanized monoclonal antibody targeting interferon alpha (IFNα) that has immunomodulatory potential. It was humanized from a mouse monoclonal as described in , and peptide sequences of the antibody (identified as humanized 9F3v13) are claimed in Genentech patent US7582445 .
Rontalizumab is functionally similar to sifalimumab. Development of both of these anti-IFNα agents has been discontinued. Compare these with anifrolumab, which targets the type I interferon receptor (IFNAR1) rather than the ligand itself, and which has progressed to Phase 3 clinical trial.
A 3D X-ray structure of rontalizumab's Fab domain bound to IFNα2 has been published (PDB identifier 4Z5R) .