Adult Patients with Narcolepsy

The efficacy of WAKIX for the treatment of excessive daytime sleepiness in adult patients with narcolepsy was evaluated in two multicenter, randomized, double-blind, placebo-controlled studies (Study 1; NCT01067222 and Study 2; NCT01638403). Patients ≥18 years of age who met the International Classification of Sleep Disorders (ICSD-2) criteria for narcolepsy (with or without cataplexy) and who had an Epworth Sleepiness Scale (ESS) score ≥14 were eligible to enroll in the studies. EDS was assessed using the ESS, an 8-item questionnaire by which patients rate their perceived likelihood of falling asleep during usual daily life activities. Each of the 8 items on the ESS is rated from 0 (would never doze) to 3 (high chance of dozing); the maximum score is 24. Study 1 and Study 2 included an 8-week treatment period: a 3-week dose titration phase followed by a 5-week stable dose phase. These studies compared WAKIX to both a placebo and an active control. 

In Study 1, 95 patients were randomized to receive WAKIX, placebo, or active control. The dose of WAKIX was initiated at 8.9 mg once daily and could be increased at weekly intervals to 17.8 mg or 35.6 mg, based on clinical response and tolerability. No dose adjustments were permitted during the 5-week stable dose phase. 61% of patients reached a stable dose of 35.6 mg. Median age in the study was 37 years. More than 90% of patients in the WAKIX and placebo groups were Caucasian and 54% were male. Approximately 80% of the population had a history of cataplexy. 

WAKIX demonstrated statistically significantly greater improvement on the primary endpoint, the least square mean final ESS score compared to placebo (Table 3). 

In Study 2, 166 patients were randomized to receive WAKIX, placebo, or active control. The dose of WAKIX was initiated at 4.45 mg and could be increased at weekly intervals to 8.9 mg or 17.8 mg, based on clinical response and tolerability. No dose adjustments were permitted during the 5-week stable-dose phase. 76% of patients reached a stable dose of 17.8 mg. Median age in the study was 40 years. In the WAKIX and placebo groups, approximately 50% of patients were male, 90% of patients were Caucasian, and 75% of patients had a history of cataplexy.

WAKIX demonstrated statistically significantly greater improvement on the primary endpoint, the least square mean final ESS score compared to placebo (Table 3).

Examination of demographic subgroups by sex did not suggest differences in response.

The efficacy results from Study 1 and Study 2 are shown in Table 3.

Figure 6 shows the ESS score from baseline to Week 8 in Study 1.

  


Figure 6: Epworth Sleepiness Scale Score (mean ± SEM) from Baseline to Week 8 in Study 1

  
SEM = standard error of the mean (raw mean scores)   
ESS scores range from 0 to 24, with 0 being the best score and 24 being the worst score

Pediatric Patients (6 years of age and older) with Narcolepsy

The efficacy of WAKIX for the treatment of excessive daytime sleepiness in pediatric patients 6 years of age and older with narcolepsy was evaluated in one multicenter, randomized, double-blind, placebo-controlled study (Study 4; NCT02611687). Pediatric patients 6 to 17 years who met the International Classification of Sleep Disorders (ICSD-3) criteria for narcolepsy (with or without cataplexy) and who had a Pediatric Daytime Sleepiness Scale (PDSS) score ≥15 were eligible to enroll in the study. EDS was assessed with the PDSS, an 8-item questionnaire in which patients report their frequency of EDS-related symptoms. Each of the 8 items on the PDSS is rated from 0 (never) to 4 (very often, always); the maximum score is 32, with higher scores representing greater severity of symptoms. The study included an 8-week treatment period: a 4-week dose titration phase followed by a 4-week stable dose phase.

In Study 4, 110 pediatric patients 6 to 17 years were randomized to receive WAKIX or placebo. The dose of WAKIX was initiated at 4.45 mg once daily and could be increased at weekly intervals to 17.8 mg for patients weighing <40 kg or 35.6 mg for patients weighing≥40 kg, based on clinical response and tolerability. No dose adjustments were permitted during the 4-week stable dose phase. 69% of patients weighing <40 kg reached a stable dose of 17.8 mg and 72% of patients weighing ≥40 kg reached a stable dose of 35.6 mg. Median age in the study was 13 years, 56% of the patients were male, and 82% of the population had a history of cataplexy. Race and ethnicity were not collected in this study.

WAKIX demonstrated statistically significantly greater improvement on the least square mean change from baseline to the end of treatment in final PDSS total score compared to placebo, of -3.41 points (95% CI: -5.52, -1.31). Study 4 included global assessments, which showed positive trends supporting PDSS total score of improvement in favor of WAKIX.