DK 221 

DK 221 is a PD-L1 blocker with an IC₅₀ of 24.5 nM for inhibiting the binding of PD-L1 to PD-1. DK 221 reduces the uptake of [¹⁸F]DK222 in PD-L1-positive tumor cells and mouse xenografts. DK 221 is applicable to research related to triple-negative breast cancer and melanoma^[1].

DK 221 (1 μM; 30 min) specifically blocks ^[18F]DK222 binding to PD-L1 in PD-L1-positive CHO-hPD-L1, LOX-IMVI, MDAMB231, and SUM149 cells, with >90% reduction in radioactivity uptake^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

DK221 (50 mg/kg; 30 min prior to [¹⁸F]DK222 injection) specifically blocks [¹⁸F]DK222 binding to PD-L1 in MDAMB231 breast cancer xenografts, resulting in a 79% reduction in radiotracer tumor uptake at a dose of 50 mg/kg^[1].
DK221 (50 mg/kg; 30 min prior to [¹⁸F]DK222 injection) specifically blocks [¹⁸F]DK222 binding to PD-L1 in LOX-IMVI melanoma xenografts, resulting in significantly reduced radiotracer tumor uptake at a dose of 50 mg/kg^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

1956.18

C₉₂H₁₂₆N₂₂O₂₄S

1886065-39-9

Cyclo(Ac-Tyr-NMeAla-Asn-Pro-His-Glu-Hyp-Trp-Ser-Trp(carboxymethyl)-NMeNle-NMeNle-Lys-Cys)-Gly-NH2

Cyclo(Ac-Y-NMeAla-NPHEWS-Trp(carboxymethyl)-NMeNle-NMeNle-KC)-G-NH2

CN([C@H](C(N[C@H](C(NCC(N)=O)=O)CSCC(N[C@H]1CC2=CC=C(O)C=C2)=O)=O)CCCCN)C([C@@H](N(C([C@@H](NC([C@@H](NC([C@@H](NC([C@@H](NC([C@@H]3C[C@@H](O)CN3C([C@@H](NC([C@@H](NC([C@@H]4CCCN4C([C@@H](NC([C@@H](N(C1=O)C)C)=O)CC(N)=O)=O)=O)CC5=CNC=N5)=O)CCC(O)=O)=O)=O)CC6=CNC7=CC=CC=C76)=O)CO)=O)CC(C8=CC=CC=C89)=CN9CC(O)=O)=O)CCCC)=O)C)CCCC)=O

Room temperature in continental US; may vary elsewhere.

Please store the product under the recommended conditions in the Certificate of Analysis.

• [1]. Kumar D, et al. Pharmacodynamic measures within tumors expose differential activity of PD(L)-1 antibody therapeutics. Proc Natl Acad Sci U S A. 2021 Sep 14;118(37):e2107982118.  [Content Brief]