A benzylphthalazinyl compound that blocks the binding of the Smoothened (Smo) agonist Hh-Ag1.5 to Smo in competitive binding assays (IC₅₀ = 5 or 8 nM, respectively, using CHO-K1 membrane expressing murine or human Smo) and potently inhibits Gli-mediated transcription activity upon Hh-Ag1.5 stimulation in TM3-based reporter assays (IC₅₀ = 2.7 or 35 nM, respectively, against 1 or 25 nM Hh-Ag1.5). Shown to exhibit blood-brain barrier permeability and good oral bioavailability in mice and effectively inhibit tumor growth in a dose-dependent manner in a Ptch^+/-p53^-/- medulloblastoma allograft model in Harlan nu/nu mice (71% regression by two 40 mg/kg oral dosages per day) in vivo.

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 3 months at -20°C.