CGP-53153 competitively inhibits rat microsomal 5 alpha-reductase from the prostate (IC50: 36 nM) compared to the reference compound finasteride (IC50: 11 nM).

CGP-53153 (0.01 mg/kg, p.o.) can significantly reduce T-propionate-mediated prostate growth. CGP-53153 significantly reduces prostate weight at 3 and 10 mg/kg by 31% and 37%, respectively. Treatment for 12 weeks with both CGP-53153 reduces prostate volume by more than 70% in individual dogs. Neither body weight nor the weight of any organ tested is affected by CGP-53153.