OKT3

https://doi.org/10.1351/goldbook.13523
Brand name for muromonab-CD3, an immunosuppressant drug given intravenously to reverse acute rejection of transplanted organs, including the heart, kidneys, and liver.
Note: OKT3 was the first monoclonal antibody used to treat patients.
Source:
PAC, 2012, 84, 1113. (IUPAC glossary of terms used in immunotoxicology (IUPAC Recommendations 2012)) on page 1223 [Terms] [Paper]