15-deoxy-.DELTA.12,14-PGD2 is a synthetic analog of PGD2 and a potential precursor to the PPARγ ligand 15-deoxy-.DELTA.12,14-PGJ2.{1424} It possesses cytotoxic effects on L1210 mouse leukemia cells in vitro with an IC50 of 0.3 μg/ml. 15-deoxy-.DELTA.12,14-PGD2 is 10-fold more potent than PGD2 in this activity.{334} However, it is a less effective inhibitor of ADP-induced platelet aggregation (IC50 = 320 ng/ml) compared to PGD2 (IC50 = 3 ng/ml).{1139}