The objective of this study is to evaluate and compare the efficacy and safety of escalating doses of BF2.649 and BF2.649 add on Modafinil on cataplexy in patients with narcolepsy

BF 2.649, a new molecule, reduces significantly the diurnal sleepiness and demonstrated its anti-cataplexy effect in pre-clinical and clinical studies.

The objective of this POC study are firstly to evaluate and compare the efficacy and safety of escalating doses of BF2.649 and BF2.649 add on Modafinil (200 mg/day) on cataplexy attacks, and secondly to evaluate the additive/synergistic effect and safety of the combination of BF2.649 and Modafinil on EDS as assessed by both of objective and subjective measures including ESS, MWT, patients sleep diary.

Inclusion Criteria:

• "De novo" patients with newly diagnosed narcolespy and cataplexy , and not taking any treatment for Excessive Daytime Sleepiness(EDS) and cataplexy
• patients with previously diagnosed narcolepsy and cataplexy and not taking any treatment for EDS and cataplexy for more than 3 months
• partial or total cataplexy attacks with a frequency of at least 5 per week during a 14 day baseline period and ESS >or= 14 at the end of the baseline period

Exclusion Criteria:

• Patients who are unable or unwilling to temporarily discontinue any no-authorized drugs or substances
• Current or recent history of a substance abuse or dependence disorder including alcohol abuse
• Psychiatric and neurological disorders such as psychosis or dementia, bipolar illness, severe anxiety, clinical depression, history of seizure disorder or other problem that in the investigator's opinion would preclude the patient's participation