Evaluation of Safety & Tolerability of Multiple Dose Regimens of CHF 5074 and Exploration of Effects on Potential Markers of Clinical Efficacy in Patients With Mild Cognitive Impairment - Prolonged Open Label Extension Phase

Inclusion Criteria: * Diagnosis of amnestic or non-amnestic Mild Cognitive Impairment. * Mini-Mental State Examination score higher than 24 at screening. * MRI scan of the brain at screening with fluid-attenuation inversion recovery (FLAIR) and T2\*-weighted gradient-recalled-echo (GRE) sequences. Exclusion Criteria: * Diagnosis of Alzheimer's disease according to the (DSM-IV-TR) or NINCDS-ADRDA criteria. * Any medical condition that could explain the patients cognitive deficits. * CT or MRI brain imaging results obtained within 12 months prior to baseline showing evidence of infection, infarction, or focal lesions of clinical significance * MRI scan at screening showing more than 4 cerebral microhemorrhages (lesions with diameter ≤ 10 mm). * Geriatric Depression Scale (30-point scale) score \> 9 at screening. * History of stroke. * Modified Hachinski ischemic scale score \> 4 at screening. * Women of childbearing potential. * Vitamin B12 or folate deficiency. * Diagnosis of schizophrenia or recurrent mood disorder (including unipolar and bipolar disorders) within 3 years of screening. * Current diagnosis of peptic ulcer or gastrointestinal bleeding within the last year and/or chronic inflammatory bowel disease. * Concomitant use of donepezil at doses \> 5 mg/day or other cholinesterase inhibitors (rivastigmine or galantamine) at any dose. * Concomitant use of memantine at dose \> 20 mg/day. * Concomitant use of psychoactive drugs (sedatives, hypnotics, etc).