Lintuzumab (SGN-33) is a humanized monoclonal antibody used in the treatment of cancer. The drug had been developed by Seattle Genetics as a treatment for acute myeloid leukemia (AML), a condition which results in the deaths of 9,000 people a year in the United States. Lintuzumab targets the CD33 protein, which is expressed in AML and other myeloproliferative diseases, but does not appear in abundance on normal cells.
Trials for AML were abandoned in 2010 when a phase IIb trial failed to show increased survival.
As of 2010, Seattle Genetics was conducting Phase II trials of lintuzumab in conjunction with bortezomib (marketed as Velcade) as a treatment for those with myelodysplastic syndromes.