of IL-2, which was finally approved by the FDA as Proleukin for metastatic renal carcinoma in 1992. By 1993 aldesleukin was the only approved version of IL-2, but Roche was also developing a proprietary, modified, recombinant IL-2 called teceleukin, with a methionine added at is N-terminal, and Glaxo was developing a version called bioleukin, with a methionine added at is N-terminal and residue 125 replaced with alanine. Dozens of clinical trials had been conducted of recombinant or purified IL-2, alone, in combination with other drugs, or using cell therapies, in which cells were taken from patients, activated with IL-2, then reinfused. Novartis acquired Chiron in 2006 and licensed the US aldesleukin business to Prometheus Laboratories in 2010 before global rights to Proleukin were subsequently acquired by Clinigen in 2018 and 2019. References External links Proleukin website IL-2 Signaling Pathway Interleukins Immunostimulants Cancer treatments Immunomodulating drugs Immunology