In a clinical trial with patients with mild to moderate AD using rifampicin, a potent inducer of P-gp, a reduced cognitive decline was observed after 12 months of treatment, presumably because the drug was able to improve the clearance of Aβ from the brain via the enhancement of P-gp mediated transport (Loeb et al., 2004). The gene discussed is PGP; the disease is Alzheimer disease.