The present invention relates to biphenyl-ethyl-pyrrolidine derivatives of Formula (Ia) and pharmaceutically acceptable salts, solvates, and hydrates thereof, that modulate the activity of the histamine H3 receptor (H3R): Compounds of the present invention and pharmaceutical compositions thereof are for use in methods for the treatment of histamine H3-associated disorders, such as treatment of cognitive disorders, epilepsy, brain trauma, depression, obesity, disorders of sleep and wakefulness such as excessive daytime sleepiness, narcolepsy, shift-work sleep disorder, drowsiness as a side effect from a medication, maintenance of vigilance to aid in the completion of tasks and the like, cataplexy, hypersomnia, somnolence syndrome, jet lag, sleep apnea and the like, attention deficit hyperactivity disorder (ADHD), schizophrenia, allergies, allergic responses in the upper airway, allergic rhinitis, nasal congestion, dementia, Alzheimer's disease, pain and pruritus.La présente invention concerne des composés de formule (Ia) et leurs sels, solvates et hydrates pharmaceutiquement acceptables, qui modulent l'activité du récepteur H3 de l'histamine. Les composés de la présente invention et leurs compositions pharmaceutiques sont dirigés vers des procédés utiles dans le traitement de troubles associés à l'histamine H3.
