CPI-169 (R-enantioMer)

CPI-169 (CPI 169 R-enantiomer) inhibits the catalytic activity of PRC2 with an IC ₅₀ of < 1nM, decreases cellular levels of H3K27me3 with an EC ₅₀ of 70 nM, and triggers cell cycle arrest and apoptosis in a variety of cell lines. In KARPAS-422 cells, CPI-169 shows a dose-dependent inhibitory effect on cell viability, and produces synergy anti-proliferative activity when used in combination with ABT-199. In 16 out of 25 NHL cell lines, CPI-169 also suppresses cell growth with GI ₅₀ of <5 μM.

CPI-169 (CPI 169 R-enantiomer) (200 mpk, s.c. BID) is well tolerated in mice with no observed toxic effect or body weight loss. CPI-169 treatment leads to tumor growth inhibition (TGI) of an EZH2 mutant KARPAS-422 DLBCL xenograft. CPI-169 (100 mpk, BID) with a single dose of CHOP leads tumors to rapidly regress and become unpalpable. In mice bearing KARPAS-422 xenografts, CPI-169 (200 mg/kg, s.c.) effectively suppresses H3K27me3 levels and results in lymphoma tumor regression without affecting body weight or causing any overt adverse effects.