Therapies for narcolepsy with or without cataplexy: evidence-based review

Relationship between sleep efficacy endpoints and measures of functional status and health-related quality of life in participants with narcolepsy or obstructive sleep apnea treated for excessive daytime sleepiness

This study examined the correlation between improvements in excessive daytime sleepiness in participants with obstructive sleep apnea or narcolepsy and changes in functional status, work productivity and health-related quality of life. Data from two 12-week randomized controlled trials of solriamfetol were analyzed. Participants completed the Epworth Sleepiness Scale, 10-item Functional Outcomes of Sleep Questionnaire, Work Productivity and Activity Impairment questionnaire and 36-Item Short Form Health Survey and performed the Maintenance of Wakefulness Test at baseline and weeks 4, 8 and 12. Patient Global Impression of Change was assessed at weeks 4, 8 and 12. Pearson correlations were calculated for change in scores from baseline to week 12. For both studies, changes in the 10-item Functional Outcomes of Sleep Questionnaire were highly correlated (absolute value >0.5) with changes in Epworth Sleepiness Scale scores; changes in multiple domain scores of the 36-Item Short Form Health Survey and Work Productivity and Activity Impairment questionnaire were moderately correlated (0.3-0.5) with changes in Epworth Sleepiness Scale scores in both studies and highly correlated for participants with narcolepsy. Changes in Maintenance of Wakefulness Test scores correlated moderately with changes in Epworth Sleepiness Scale scores in both studies. At week 12, Patient Global Impression of Change ratings correlated highly with Epworth Sleepiness Scale and 10-item Functional Outcomes of Sleep Questionnaire scores for both disorders. Other correlations were low. Self-reported assessments of sleepiness and global improvement appear to be more strongly correlated with measures of functioning and health-related quality of life than objectively assessed sleepiness.

Evaluation of the effect of JZP-110 in patients with narcolepsy assessed using the Maintenance of Wakefulness Test censored to 20 minutes

OBJECTIVE

To evaluate the effects of JZP-110 on the Maintenance of Wakefulness Test (MWT) with data censored to include only the first 20 min of a 40-min MWT.

METHODS

In a 4-week, placebo-controlled crossover design (Study 201; N = 33) and a 12-week parallel-group design (Study 202; N = 93), JZP-110 was evaluated in narcolepsy patients using changes from baseline in the 40-min MWT as the primary endpoint. Effect sizes based on the change from baseline in mean MWT sleep latency were calculated using 20-min censored MWT data and compared to 40-min MWT data.

RESULTS

In Study 201, mean (standard deviation) changes in MWT sleep latency were 12.7 (10.6) min with JZP-110 versus 0.9 (6.0) min with placebo (P = 0.0002) for 40-min data, and 8.9 (6.3) versus 0.4 (4.6) min for 20-min censored data (P < 0.0001). In Study 202, mean changes in MWT sleep latency were 12.8 (10.3) min with JZP-110 versus 2.1 (7.9) min with placebo (P < 0.0001) for 40-min data, and 8.9 (5.5) versus 1.1 (5.6) min for 20-min censored data (P < 0.0001). In Studies 201 and 202, respectively, Cohen's d effect sizes were large and numerically greater for 20-min censored data (1.54 and 1.41) versus 40-min data (1.37 and 1.17).

CONCLUSIONS

In patients with narcolepsy, JZP-110 significantly improved the ability to stay awake compared with placebo, with large effect sizes using both the 40-min and 20-min censored MWT data.

Effect of Oral JZP-110 (ADX-N05) on Wakefulness and Sleepiness in Adults with Narcolepsy: A Phase 2b Study

STUDY OBJECTIVES

To evaluate the efficacy and safety of oral JZP-110, a second-generation wake-promoting agent with dopaminergic and noradrenergic activity, for treatment of impaired wakefulness and excessive sleepiness in adults with narcolepsy.

METHODS

This was a phase 2b, randomized, double-blind, placebo-controlled, parallel-group trial conducted at 28 centers in the United States. Patients were adults with narcolepsy who had baseline scores ≥ 10 on the Epworth Sleepiness Scale (ESS) and baseline sleep latency ≤ 10 min on the Maintenance of Wakefulness Test (MWT). Patients received a daily placebo (n = 49) or JZP-110 (n = 44) 150 mg/day weeks 1-4 and 300 mg/day weeks 5-12. Primary efficacy endpoints were change from baseline in average MWT sleep latency, and the Clinical Global Impression-Change (CGI-C); secondary endpoints were change from baseline in ESS score and Patient Global Impression-Change.

RESULTS

Improvements were significantly greater with JZP-110 versus placebo on mean MWT sleep latency (4 w, 9.5 versus 1.4 min, P < 0.0001; 12 w, 12.8 versus 2.1 min, P < 0.0001), percentage of patients with CGI-C improvement (4 w, 80% versus 51%, P = 0.0066; 12 w, 86% versus 38%, P < 0.0001), and mean change in ESS (4 w, -5.6 versus -2.4, P = 0.0038; 12 w, -8.5 versus -2.5, P < 0.0001). Three JZP-110-treated patients (6.8%) discontinued due to adverse events (AEs). The most common AEs with JZP-110 versus placebo were insomnia (23% versus 8%), headache (16% versus 10%), nausea (14% versus 6%), diarrhea (11% versus 6%), decreased appetite (14% versus 0%), and anxiety (11% versus 0%).

CONCLUSIONS

At doses of 150-300 mg/day, JZP-110 was well tolerated and significantly improved the ability to stay awake and subjective symptoms of excessive sleepiness in adults with narcolepsy.

CLINICAL TRIALS REGISTRATION

Clinicaltrials.gov identifier NCT01681121.

Effect of oral JZP-110 (ADX-N05) treatment on wakefulness and sleepiness in adults with narcolepsy

BACKGROUND

JZP-110 is a wake-promoting agent with dopaminergic and noradrenergic activity.

METHODS

This double-blind, crossover study, randomized adults with narcolepsy with or without cataplexy (N = 33) to placebo or JZP-110 at 150 mg/day (weeks 1 and 3) increased to 300 mg/day (weeks 2 and 4). Patients had to have baseline Epworth Sleepiness Scale (ESS) scores ≥10 and mean sleep latencies ≤10 min on the Maintenance of Wakefulness Test (MWT). Efficacy end points included MWT sleep latency and ESS, and the percentage of patients improved on the Clinical Global Impression of Change.

RESULTS

Patients were primarily male (57.6%) and white (69.7%), with a mean (standard deviation) age of 37.1 (12.4) years. At two weeks, the change in the mean MWT sleep latency was 11.8 min longer with JZP-110 than with placebo (P = 0.0002); JZP-110 resulted in greater changes in sleep latency on each MWT trial (P <0.001). For ESS, JZP-110 was more efficacious relative to placebo after 1 (P <0.0001) and two weeks (P = 0.0002); final ESS scores were 10.8 with JZP-110 and 15.2 with placebo, changes of -6.7 and -2.4, respectively. JZP-110 was generally well tolerated; the most common adverse events with JZP-110 were nausea (12%), noncardiac chest discomfort (9.1%), and headache (9.1%).

CONCLUSIONS

The efficacy of JZP-110 for impaired wakefulness and excessive sleepiness was observed at 150-300 mg/day and as early as one week after initiating treatment (Clinicaltrials.gov identifier NCT01485770).

Neuropsychological findings in childhood narcolepsy

Narcolepsy with cataplexy is a severely disabling disorder very often arising in childhood. Data on neuropsychological impairment in children are scant. We administered standardized neuropsychological tests to 13 children with narcolepsy with cataplexy. Overall, our patients displayed multiple patterns of cognitive and behavioral dysfunction, and often academic failure (7 cases out of 13). All children had a normal full intelligence quotient (IQ), but 3 patients presented a significantly higher and 2 a significantly lower Verbal IQ compared to Performance IQ, respectively. Mean sleep latency was significantly correlated (P < .05) to alertness functions. Eight patients displayed behavioral problems: emotional symptoms and conduct problems prevailed. Childhood narcolepsy with cataplexy represents a risk factor for subtle and heterogeneous cognitive impairments potentially resulting in academic failure, despite the normal IQ. These children also have a certain psychopathological risk. All this seems to be at least partially detached from the direct effects of daytime sleepiness.

Effects of hypocretin/orexin cell transplantation on narcoleptic-like sleep behavior in rats

The sleep disorder narcolepsy is now considered a neurodegenerative disease because there is a massive loss of neurons containing the neuropeptide hypocretin/orexin (HCRT). In consequence, narcoleptic patients have very low cerebrospinal fluid (CSF) levels of HCRT. Studies in animal models of narcolepsy have shown the neurophysiological role of the HCRT system in the development of this disease. For example, the injection of the neurotoxin named hypocretin-2-saporin (HCRT2/SAP) into the lateral hypothalamus (LH) destroys the HCRT neurons, therefore diminishes the contents of HCRT in the CSF and induces narcoleptic-like behavior in rats. Transplants of various cell types have been used to induce recovery in a variety of neurodegenerative animal models. In models such as Parkinson's disease, cell survival has been shown to be small but satisfactory. Similarly, cell transplantation could be employed to implant grafts of HCRT cells into the LH or even other brain regions to treat narcolepsy. Here, we report for the first time that transplantation of HCRT neurons into the LH of HCRT2/SAP-lesioned rats diminishes narcoleptic-like sleep behavior. Therefore, cell transplantation may provide an effective method to treat narcolepsy.

Sodium oxybate for narcolepsy with cataplexy: systematic review and meta-analysis

STUDY OBJECTIVES

To assess the efficacy and safety of sodium oxybate (SXB) in narcolepsy-cataplexy patients.

DESIGN

Systematic review and meta-analysis.

PATIENTS

Adults with narcolepsy-cataplexy.

INTERVENTIONS

SXB.

MEASUREMENTS AND RESULTS

Electronic databases (e.g., MEDLINE) and references of included studies were searched to identify randomized controlled trials (RCTs) assessing the efficacy and safety of SXB for patients with narcolepsy-cataplexy. Risk of bias was appraised using the Cochrane risk of bias tool. Meta-analysis was conducted in Review Manager Version 5. Six RCTs and 5 companion reports were included after screening 14 full-text articles and 483 citations. All were private-industry funded. SXB (usually 9 g/night) was superior to placebo for reducing mean weekly cataplexy attacks (n = 2 RCTs, mean difference [MD]: -8.5, 95% CI: -15.3, -1.6), increasing maintenance wakefulness test (MWT) (n = 2, MD: 5.18, 95% CI: 2.59-7.78), reducing sleep attacks (n = 2, MD: -9.65, 95% CI: -17.72, -1.59), and increasing Clinical Global Impression scores (n = 3, relative risk, RR: 2.42, 95% CI: 1.77-3.32). SXB did not significantly increase REM sleep versus placebo (n = 2, MD: -0.49, 95% CI: -3.90, 2.92). Patients receiving SXB had statistically more adverse events versus placebo, including nausea (n = 3, relative risk [RR]: 7.74, 95% CI: 3.2, 19.2), vomiting (n = 2, RR: 11.8, 95% CI: 1.6, 89.4), and dizziness (n = 3, RR: 4.3, 95% CI: 1.1, 16.4). Enuresis was not significantly different from placebo (n = 2, RR: 2.6, 95% CI: 0.8, 9.8). All meta-analyses had minimal statistical heterogeneity (p-value > 0.1).

CONCLUSION

Narcolepsy patients on SXB have significant reductions in cataplexy and daytime sleepiness. SXB is well tolerated in patients with narcolepsy, and most adverse events were mild to moderate in severity.

Armodafinil in the treatment of sleep/wake disorders

Excessive sleepiness (ES) is a major but underestimated public health concern associated with significant impairments in alertness/wakefulness and significant morbidity. The term ES has been used in the sleep medicine literature for years, but due to its nonspecific symptoms (ie tiredness or fatigue), it frequently goes unrecognized or is misdiagnosed in primary care. In some cases ES arises due to poor sleep habits or self-imposed sleep deprivation; however, ES is also a key component of a number of sleep/wake disorders and multiple medical and psychiatric disorders. Identification and treatment of ES is critical to improve the quality of life and well-being of patients and for the safety of the wider community. The inability of patients to recognize the nature, extent, and symptomatic profile of sleep/wake disorders requires vigilance on the part of healthcare professionals. Interventions to address ES and its associated impairments, treatment of the underlying sleep/wake disorder, and follow-up are a priority given the potential for serious consequences if left untreated. Wakefulness-promoting agents are available that treat ES associated with sleep/wake disorders. This review examines current approaches for managing this debilitating and potentially life-threatening condition, focusing on the place of armodafinil as a wakefulness-promoting agent.

How treatment affects cognitive deficits in patients with sleep disorders: methodological issues and results

Sleep disorders are frequently associated with impaired performance although the type and extent of cognitive deficits varies widely between different types of sleep disorders. Treatment is expected to ameliorate these deficits. However, cognitive functioning and its change with treatment depend on numerous factors. In this chapter we discuss methodological issues, including test selection, and person-specific, task-specific and environmental factors that influence cognitive functioning. In addition, features of study design and sampling strategies are discussed. The chapter ends with a short overview of routes by which treatment may affect cognition in sleep-disordered patients.

Psychosocial and intellectual functioning in childhood narcolepsy

PURPOSE

This study reports the psychological assessment of 12 children referred to a narcolepsy clinic, using quantitative methods to describe intellectual and psychosocial functioning in childhood narcolepsy.

METHODS

The participants were six males and six females aged between 7-16 years (median age 10 years). The protocol included a clinical interview; the Wechsler Intelligence Scale for Children-III-UK; and the Parent version of the Achenbach Child Behaviour Checklist (CBCL).

RESULTS

Eleven children obtained an IQ in the average range (mean and median =100). However, a significant difference was found between verbal and performance scales in 42% of children, compared to WISC-III normative prevalence rates of 24%. CBCL results revealed that 10/12 children scored in the clinically significant range on the Total Score Index, with 9/12 obtaining scores in the significant range on the Internalizing Index. The majority of children presented with difficulties in discussing and describing distressing physical and psychological symptoms with parents and others.

CONCLUSIONS

These findings suggest that the psychosocial impact of narcolepsy extends beyond the effects of excessive sleepiness and that symptoms such as hallucinations can lead to significant psychological morbidity.