In contrast, the use of small molecule inducible promoter systems appears a valid option, particularly as transient therapeutic expression may still produce a therapeutic effect, as previous studies on BACE1 suggest that transient inhibition of the enzyme is sufficient to produce sustained long-term reductions of amyloid-β (Aβ) accumulation in AD (183, 184). The gene discussed is BACE1; the disease is Alzheimer disease.