Ranibizumab is a monoclonal antibody fragment (fab) created from the same parent mouse antibody as bevacizumab. it is an anti-angiogenic that has been approved to treat the "wet" type of age-related macular degeneration (amd, also armd), a common form of age-related vision loss.ranibizumab is a monoclonal antibody that inhibits angiogenesis by inhibiting vascular endothelial growth factor a, a mechanism similar to bevacizumab.