High-dose recombinant IL-2 (aldesleukin) is approved for treatment of advanced melanoma and renal cell carcinoma, however, major limitations restrict its therapeutic use. Both in vivo efficacy studies in murine tumor models as well as PD effects observed in NHP indicate that BPT-143 has a best-in-class profile among “not-alpha” IL-2 compounds currently in development. IND-enabling studies are ongoing and a first in human trial is planned to start in 2022.