BMSpep-57 hydrochloride, a potent macrocyclic peptide, competitively inhibits PD-1/PD-L1 interaction, exhibiting an IC50 value of 7.68 nM. It binds to PD-L1 with dissociation constants (Kds) of 19 nM and 19.88 nM as determined by MST and SPR assays, respectively. This compound enhances T cell functionality by promoting IL-2 production in PBMCs[1].

In a ELISA competition assay, BMSpep-57 inhibits PD-1/PD-L1 binding up to 98.1% 300 nM. And it shows a concentration dependent inhibition of PD-1/PD-L1 binding with an IC50 of 7.68 nM[1].BMSpep-57 induced high levels of IL-2 at 1 μM and 500 nM concentrations in SEB-stimulated peripheral blood mononuclear cells[1].BMSpep-57 (0.2-10 μM; 24 hours) does not show any effect on the Jurkat, CHO and HepG2 cells’ viability at the various concentrations tested[1].