Used in the treatment of moderate to severe plaque psoriasis, this antibody targets the CD11a subunit of integrin receptors on T-cells, blocking their activation and migration into skin tissues. By inhibiting T-cell involvement, it reduces the inflammatory response responsible for rapid skin cell turnover and plaque formation. It was administered subcutaneously and provided significant clinical improvement in psoriasis symptoms. However, due to the risk of progressive multifocal leukoencephalopathy (PML), a rare brain infection, its use was discontinued in many markets despite efficacy. It remains a reference tool in immunology research for studying T-cell signaling and adhesion mechanisms.