SCH-451659

SCH-451659 (STX1383) is an orally active, selective 17β-HSD3 inhibitor with an IC₅₀ of 2.4 nM against h17β-HSD3. SCH-451659 selectively blocks the conversion of androstenedione to testosterone. SCH-451659 reduces testosterone levels in mice. SCH-451659 exhibits anticancer activity against androstenedione-dependent prostate tumors^[1][2]. In Vitro:SCH-451659 potently inhibits h17β-HSD3 in 293-EBNA (HSD3) cells with an IC₅₀ of 2.4 nM, while it exhibits only extremely weak activity against 17β-HSD1 in T47D cells and 17β-HSD2 in MDA-MB-231 cells^[1].
SCH-451659 (96 h) inhibits the proliferation of LNCaPwt and PC-3 prostate cancer cells, with IC₅₀ values of 5.9 μM and 5.8 μM against the two cell lines within 96 hours^[1].
SCH-451659 (500 nM; for 15 consecutive days) inhibits the proliferation of LNCaP (HSD3) prostate cancer cells stimulated by 10 nM adione^[1]. In Vivo:SCH-451659 (20 mg/kg; subcutaneous injection; once daily; for 5 consecutive weeks) significantly inhibits the growth of androstenedione-dependent prostate tumors^[1].
SCH-451659 (20 mg/kg, subcutaneous injection, administered on days 1-5 and 8-12 for a total of 12 days) significantly reduces plasma testosterone levels in normal male MF-1 nude mice, decreasing them to 17.4% of the control group concentration^[1].
SCH-451659 (15 mg/kg; p.o.; twice daily; for 4 weeks) reduces serum testosterone levels by 50%, testicular testosterone levels by 85%, and prostate weight by 20% in cynomolgus monkeys^[2].