Efficacy and safety of modafinil in patients with idiopathic hypersomnia without long sleep time: a multicenter, randomized, double-blind, placebo-controlled, parallel-group comparison study

Clinical considerations in the treatment of idiopathic hypersomnia

Idiopathic hypersomnia typically is a chronic and potentially debilitating neurologic sleep disorder, and is characterized by excessive daytime sleepiness. In addition to excessive daytime sleepiness, idiopathic hypersomnia symptoms can include severe sleep inertia; long, unrefreshing naps; long sleep time; and cognitive dysfunction. Patients with idiopathic hypersomnia may experience a significant impact on their quality of life, work or school performance, earnings, employment, and overall health. Given the complex range of symptoms associated with idiopathic hypersomnia and the array of treatments available, there is a need to provide guidance on the treatment of idiopathic hypersomnia and the clinically relevant recommendations that enhance effective disease management. Identifying appropriate treatment options for idiopathic hypersomnia requires timely and accurate diagnosis, consideration of individual patient factors, and frequent reassessment of symptom severity. In 2021, low-sodium oxybate was the first treatment to receive approval by the US Food and Drug Administration for the treatment of idiopathic hypersomnia in adults. However, many off-label treatments continue to be used. Adjunct nonpharmacologic therapies, including good sleep hygiene, patient education and counseling, and use of support groups, should be recognized and recommended when appropriate. This narrative review describes optimal treatment strategies that take into account patient-specific factors, as well as the unique characteristics of each medication and the evolution of a patient's response to treatment. Perspectives on appropriate symptom measurement and management, and potential future therapies, are also offered.

Idiopathic hypersomnia years after the diagnosis

Little attention has been paid to the long-term development of idiopathic hypersomnia symptoms and idiopathic hypersomnia comorbidities. The aim of this study was to describe the general health of patients with idiopathic hypersomnia years after the initial diagnosis, focusing on current subjective hypersomnolence and the presence of its other possible causes. Adult patients diagnosed with idiopathic hypersomnia ≥ 3 years ago at sleep centres in Prague and Kosice were invited to participate in this study. A total of 60 patients were examined (age 47.3 ± SD = 13.2 years, 66.7% women). In all participants, their hypersomnolence could not be explained by any other cause but idiopathic hypersomnia at the time of diagnosis. The mean duration of follow-up was 9.8 + 8.0 years. Fifty patients (83%) reported persisting hypersomnolence, but only 33 (55%) had no other disease that could also explain the patient's excessive daytime sleepiness and/or prolonged sleep. In two patients (3%), the diagnosis in the meantime had changed to narcolepsy type 2, and 15 patients (25%) had developed a disease or diseases potentially causing hypersomnolence since the initial diagnosis. Complete hypersomnolence resolution without stimulant treatment lasting longer than 6 months was reported by 10 patients (17%). To conclude, in a longer interval from the diagnosis of idiopathic hypersomnia, hypersomnolence may disappear or may theoretically be explained by another newly developed disease, or the diagnosis may be changed to narcolepsy type 2. Thus, after 9.8 years, only 55% of the examined patients with idiopathic hypersomnia had a typical clinical picture of idiopathic hypersomnia without doubts about the cause of the current hypersomnolence.

Long-term efficacy and safety of low-sodium oxybate in an open-label extension period of a placebo-controlled, double-blind, randomized withdrawal study in adults with idiopathic hypersomnia

STUDY OBJECTIVES

To evaluate 6-month efficacy and safety of low-sodium oxybate in people with idiopathic hypersomnia during an open-label extension period (OLE) of a phase 3 clinical trial.

METHODS

Efficacy measures included the Epworth Sleepiness Scale (ESS), Idiopathic Hypersomnia Severity Scale (IHSS), Patient Global Impression of Change (PGIc), Functional Outcomes of Sleep Questionnaire, short version (FOSQ-10), and Work Productivity and Activity Impairment Questionnaire: Specific Health Problem (WPAI:SHP). Treatment-emergent adverse events were collected throughout the OLE.

RESULTS

The OLE population included 106 participants. Most were female (71%) and White (83%), and the mean (SD) age was 41.0 (13.8) years. ESS scores decreased (improved) during the OLE (mean [SD], study baseline: 16.3 [2.8]; OLE week 2: 6.7 [4.7]; OLE end: 5.3 [3.7]), and IHSS total scores trended toward a decrease (study baseline: 32.6 [7.3]; OLE week 2: 16.2 [8.9]; OLE end: 14.8 [8.6]. Median (minimum, maximum) paired differences from OLE week 2 to OLE end were ESS, -1.0 (-20, 7; nominal P = .012); IHSS, -1.0 (-31, 19; nominal P = .086). The proportion of participants reporting PGIc ratings of "very much improved" increased from 36.7% at OLE week 2 to 53.8% at the OLE end. The FOSQ-10 and WPAI:SHP scores remained stable during OLE. The incidence of newly reported treatment-emergent adverse events decreased over the duration of the OLE.

CONCLUSIONS

Efficacy and safety of low-sodium oxybate were maintained or improved during the 6-month OLE, supporting long-term treatment with low-sodium oxybate in adults with idiopathic hypersomnia.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: A Multicenter Study of the Efficacy and Safety of JZP-258 in the Treatment of Idiopathic Hypersomnia (IH) With an Open-label Safety Extension; URL: https://clinicaltrials.gov/study/NCT03533114; Identifier: NCT03533114 and Registry: EU Clinical Trials; Name: A Double-blind, Placebo-controlled, Randomized Withdrawal, Multicenter Study of the Efficacy and Safety of JZP-258 in the Treatment of Idiopathic Hypersomnia (IH) with an Open-label Safety Extension; URL: https://www.clinicaltrialsregister.eu/ctr-search/trial/2018-001311-79/results; Identifier: 2018-001311-79.

CITATION

Morse AM, Dauvilliers Y, Arnulf I, et al. Long-term efficacy and safety of low-sodium oxybate in an open-label extension period of a placebo-controlled, double-blind, randomized withdrawal study in adults with idiopathic hypersomnia. J Clin Sleep Med. 2023;19(10):1811-1822.

Idiopathic hypersomnia and Kleine-Levin syndrome

Idiopathic hypersomnia (IH) and Kleine-Levin syndrome (KLS) are rare disorders of central hypersomnolence of unknown cause, affecting young people. However, increased sleep time and excessive daytime sleepiness (EDS) occur daily for years in IH, whereas they occur as relapsing/remitting episodes associated with cognitive and behavioural disturbances in KLS. Idiopathic hypersomnia is characterized by EDS, prolonged, unrefreshing sleep at night and during naps, and frequent morning sleep inertia, but rare sleep attacks, no cataplexy and sleep onset in REM periods as in narcolepsy. The diagnosis requires: (i) ruling out common causes of hypersomnolence, including mostly sleep apnea, insufficient sleep syndrome, psychiatric hypersomnia and narcolepsy; and (ii) obtaining objective EDS measures (mean latency at the multiple sleep latency test≤8min) or increased sleep time (sleep time>11h during a 18-24h bed rest). Treatment is similar to narcolepsy (except for preventive naps), including adapted work schedules, and off label use (after agreement from reference/competence centres) of modafinil, sodium oxybate, pitolisant, methylphenidate and solriamfetol. The diagnosis of KLS requires: (i) a reliable history of distinct episodes of one to several weeks; (ii) episodes contain severe hypersomnia (sleep>15h/d) associated with cognitive impairment (mental confusion and slowness, amnesia), derealisation, major apathy or disinhibited behaviour (hypersexuality, megaphagia, rudeness); and (iii) return to baseline sleep, cognition, behaviour and mood after episodes. EEG may contain slow rhythms during episodes, and rules out epilepsy. Functional brain imaging indicates hypoactivity of posterior associative cortex and hippocampus during symptomatic and asymptomatic periods. KLS attenuates with time when starting during teenage, including less frequent and less severe episodes. Adequate sleep habits, avoidance of alcohol and infections, as well as lithium and sometimes valproate (off label, after agreement from reference centres) help reducing the frequency and severity of episodes, and IV methylprednisolone helps reducing long (>30d) episode duration.

Safety and pharmacodynamics of a single infusion of danavorexton in adults with idiopathic hypersomnia

STUDY OBJECTIVES

Idiopathic hypersomnia (IH) is a chronic disorder characterized by excessive daytime sleepiness unexplained by another disorder or drug/medication use. Although the orexin system plays a role in sleep-wake regulation, orexin A levels in the cerebrospinal fluid are normal in people with IH. This phase 1b, randomized, placebo-controlled, crossover study aimed to investigate the safety, pharmacokinetics, and pharmacodynamics of danavorexton, a small-molecule orexin-2 receptor agonist, in adults with IH.

METHODS

Adults with IH aged 18-75 years were randomized to one of two treatment sequences of single intravenous infusions of danavorexton 112 mg and placebo. Pharmacodynamic endpoints included the maintenance of wakefulness test (MWT), the Karolinska Sleepiness Scale (KSS), and the psychomotor vigilance task (PVT). Adverse events were monitored throughout the study period.

RESULTS

Of 28 randomized participants, 12 (44.4%) had a treatment-emergent adverse event (TEAE) and 10 (37.0%) had a TEAE considered related to study drug, most of which were mild or moderate. Four participants (18.2%) had urinary TEAEs while receiving danavorexton, all of which were mild in severity. There were no deaths or TEAEs leading to discontinuation. Improvements in MWT, KSS, and PVT scores were observed with danavorexton compared to placebo. Following drug administration, a mean sleep latency of 40 min (maximum value) was observed during the MWT within 2 h of danavorexton infusion in most participants.

CONCLUSIONS

A single infusion of danavorexton improves subjective and objective excessive daytime sleepiness in people with IH with no serious TEAEs, indicating orexin-2 receptor agonists are promising treatments for IH. Clinical Trial: Clinicaltrials.gov. https://clinicaltrials.gov/ct2/show/NCT04091438.

Central Disorders of Hypersomnolence

OBJECTIVE

The goals of this article are to describe the clinical approach to and management of patients with central disorders of hypersomnolence, and to understand and differentiate available diagnostic tools.

LATEST DEVELOPMENTS

Updated clinical practice guidelines for the treatment of central disorders of hypersomnolence and narcolepsy specifically highlight new treatment options. Approval for a lower-sodium oxybate formulation that contains 92% less sodium than the standard sodium oxybate for the treatment of narcolepsy and idiopathic hypersomnia adds to the number of medications available for these disorders, allowing for a more tailored management of symptoms.

ESSENTIAL POINTS

Central disorders of hypersomnolence are characterized by excessive daytime sleepiness that impacts daily functions. These disorders can be differentiated by obtaining a detailed clinical sleep history and by a thoughtful interpretation of sleep diagnostic testing. Tailoring treatment approaches to meet the needs of individuals and accounting for medical and psychiatric comorbidities may improve quality of life.

Update on the treatment of idiopathic hypersomnia: Progress, challenges, and expert opinion

Idiopathic hypersomnia is a central hypersomnolence disorder of unknown origin characterized by excessive daytime sleepiness despite normal or long sleep time, and frequent severe sleep inertia. Management strategies have been largely derived from expert consensus, due to a lack of disease-specific assessments and reliance on case series and rare randomized controlled studies. Guidelines recommend treatment with off-label medications. Modafinil, which was approved for idiopathic hypersomnia until 2011 in Europe, is the most commonly used treatment and improved sleepiness in two recent randomized placebo-controlled trials. In 2021, low-sodium oxybate (LXB) was approved in the United States for idiopathic hypersomnia. In a placebo-controlled, double-blind, randomized withdrawal study, LXB reduced daytime sleepiness and sleep inertia, and improved daily functioning. Here, treatment options are reviewed considering the authors' professional experience, current guidelines, and the latest research developments. The choice of pharmacotherapy should be guided by symptom profile, age, comorbidities (eg, depressive symptoms, cardiovascular problems), and concomitant medications (eg, oral contraceptives). Nonpharmacologic approaches have a role in management. An instrument (idiopathic hypersomnia severity scale) has been validated in idiopathic hypersomnia specifically, opening a path to better assessment of symptoms, impact, and response to treatment. Continued research on idiopathic hypersomnia is needed to support treatment algorithms.

Clinical considerations for the diagnosis of idiopathic hypersomnia

Idiopathic hypersomnia is a sleep disorder of neurologic origin characterized by excessive daytime sleepiness, with sleep inertia, long, unrefreshing naps, and prolonged nighttime sleep being key symptoms in many patients. Idiopathic hypersomnia is described in the International Classification of Sleep Disorders, 3rd Edition as a central disorder of hypersomnolence with distinct clinical features and diagnostic criteria; however, confirming the diagnosis of idiopathic hypersomnia is often challenging. Diagnosis of idiopathic hypersomnia is based on objective sleep testing and the presence of associated clinical features but may be difficult for clinicians to recognize and correctly diagnose because of its low prevalence, clinical heterogeneity, and symptoms, which are similar to those of other sleep disorders. The testing required for diagnosis of idiopathic hypersomnia also presents logistical barriers, and reliability of objective sleep measures is suboptimal. The pathophysiology of idiopathic hypersomnia remains unknown. In this review, clinical considerations related to the pathogenesis, diagnosis, and management of idiopathic hypersomnia will be discussed, including perspectives from the European Union and United States.

Precision Medicine for Idiopathic Hypersomnia

Idiopathic hypersomnia (IH) includes a clinical phenotype resembling narcolepsy (with repeated, short restorative naps), and a phenotype with an excess of sleep, sleep drunkenness, drowsiness, and infrequent long, nonrestorative naps. Sleep tests reflect this heterogeneity. MSLTs are greater than 8 min in 2/3 of the cases and poorly repeatable. Sleep excess is better captured by extended monitoring identifying 11 to 16h of sleep/24 h. Patients with IH are young and more often female. Possible mechanisms of IH include deficiencies in arousal systems, inappropriate stimulation of sleep-inducing systems, and long biological night. Treatments now include robust studies of modafinil, clarithromycin, and sodium oxybate.

Efficacy and Safety of Lower-Sodium Oxybate in an Open-Label Titration Period of a Phase 3 Clinical Study in Adults with Idiopathic Hypersomnia

PURPOSE

To report the efficacy and safety of lower-sodium oxybate (LXB; Xywav^®) during the open-label titration and optimization period (OLT) and stable-dose period (SDP) in a clinical study for the treatment of idiopathic hypersomnia.

PATIENTS AND METHODS

Data were collected during treatment titration and optimization in a phase 3 randomized withdrawal trial in adults (18-75 years of age) with idiopathic hypersomnia who took LXB treatment (once, twice, or thrice nightly, administered orally) in the OLT (10-14 weeks), followed by the 2-week, open-label SDP. Endpoints included the Epworth Sleepiness Scale (ESS), Idiopathic Hypersomnia Severity Scale (IHSS), Patient Global Impression of Change, Clinical Global Impression of Change, Functional Outcomes of Sleep Questionnaire (FOSQ)-10, and Work Productivity and Activity Impairment Questionnaire: Specific Health Problem (WPAI:SHP).

RESULTS

The safety population included 154 participants; the modified intent-to-treat population comprised 115 participants. During open-label treatment, mean (SD) ESS scores improved (decreased) from 15.7 (3.8) at baseline to 6.1 (4.0) at end of SDP, and IHSS scores improved (decreased) from 31.6 (8.3) to 15.3 (8.5). Improvements were also observed during OLT in each individual IHSS item and in FOSQ-10 and WPAI:SHP scores. Thirty-five (22.7%) participants discontinued during OLT and SDP, 22 (14.3%) due to treatment-emergent adverse events (TEAEs) during OLT and SDP. The most frequent TEAEs in the first 4 weeks were nausea, headache, dizziness, and dry mouth; TEAE incidence decreased throughout OLT and SDP (weeks 1-4, n = 87 [56.5%]; weeks 13-16, n = 39 [31.7%]).

CONCLUSION

During open-label treatment with LXB, participants showed clinically meaningful improvements in idiopathic hypersomnia symptoms and in quality of life and functional measures. TEAE incidence declined over LXB titration and optimization.

Safety and efficacy of lower-sodium oxybate in adults with idiopathic hypersomnia: a phase 3, placebo-controlled, double-blind, randomised withdrawal study

BACKGROUND

Idiopathic hypersomnia is a central hypersomnolence disorder mainly characterised by excessive daytime sleepiness, with prolonged night-time sleep and pronounced sleep inertia. Until August, 2021, no medication had regulatory approval for the treatment of idiopathic hypersomnia. This study aimed to evaluate the safety and efficacy of lower-sodium oxybate in idiopathic hypersomnia.

METHODS

This was a phase 3, multicentre (50 specialist sleep centres; six EU countries and the USA), placebo-controlled, double-blind, randomised withdrawal study. Participants (aged 18-75 years) with idiopathic hypersomnia (meeting criteria from the International Classification of Sleep Disorders, 2nd or 3rd editions) began lower-sodium oxybate treatment (oral solution once or twice nightly) in an open-label titration and optimisation period (10-14 weeks), followed by a 2-week, open-label, stable-dose period. After these open-label periods, participants were randomised (1:1) by means of an interactive web recognition system, stratified by participants' baseline medication use, to either placebo or lower-sodium oxybate (individually optimised dose; range 2·5-9·0 g/night) during a 2-week, double-blind, randomised withdrawal period. To maintain masking of treatment assignment, placebo and lower-sodium oxybate oral solutions were matched in volume, appearance, and taste. During the double-blind, randomised withdrawal period, participants and investigators were unaware of treatment assignments. The primary efficacy endpoint was change in Epworth Sleepiness Scale (ESS) score from the end of the stable-dose period to the end of the double-blind, randomised withdrawal period, which was assessed in the modified intention-to-treat population (defined as all participants who were randomly assigned, took at least one dose of study medication during the double blind, randomised withdrawal period, and had at least one set of post-randomisation assessments for the primary or key secondary endpoints). Adverse events were assessed in the safety population (defined as all participants who took at least one dose of study medication). This study is registered at ClinicalTrials.gov, NCT03533114, and at EU Clinical Trials, 2018-001311-79, and is complete.

FINDINGS

Between Nov 27, 2018, and March 6, 2020, 154 participants were enrolled and comprised the safety population. ESS scores decreased from a mean of 15·7 (SD 3·8) at baseline to 6·1 (4·0) by the end of the stable-dose period. After the open-label periods, 115 participants were randomly assigned either placebo (n=59) or lower-sodium oxybate (n=56) and comprised the modified intention-to-treat population. During the double-blind, randomised withdrawal period, ESS scores increased (worsened) in participants randomly assigned to placebo but remained stable in those assigned to lower-sodium oxybate (least squares mean difference -6·5; 95% CI -8·0 to -5·0; p<0·0001). Treatment-emergent adverse events included nausea (34 [22%] of 154), headache (27 [18%] of 154), dizziness (19 [12%] of 154), anxiety (17 [11%] 154), and vomiting (17 [11%] 154). No deaths were reported during the study.

INTERPRETATION

Lower-sodium oxybate treatment resulted in a clinically meaningful improvement in idiopathic hypersomnia symptoms, with an overall safety profile consistent with that reported for narcolepsy. Lower-sodium oxybate was approved in August, 2021, by the US Food and Drug Administration for the treatment of idiopathic hypersomnia in adults.

FUNDING

Jazz Pharmaceuticals.

Medications for daytime sleepiness in individuals with idiopathic hypersomnia

BACKGROUND

Idiopathic hypersomnia is a disorder of excessive daytime sleepiness, often accompanied by long sleep times or pronounced difficulty in awakening, in the absence of a known cause. The optimal treatment strategy for idiopathic hypersomnia is currently unknown.

OBJECTIVES

To assess the effects of medications for daytime sleepiness and related symptoms in individuals with idiopathic hypersomnia and, in particular, whether medications may: 1. reduce subjective measures of sleepiness; 2. reduce objective measures of sleepiness; 3. reduce symptoms of cognitive dysfunction; 4. improve quality of life; and 5. be associated with adverse events.

SEARCH METHODS

We searched the following databases on 4 February 2021: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid, 1946 to 1 February 2021), and reference lists of articles. CRS Web includes randomized or quasi-randomized controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), the Cochrane Central Register of Controlled Trials (CENTRAL), and the specialized registers of Cochrane Review Groups, including the Cochrane Epilepsy Group. We previously searched the WHO ICTRP separately when loading of ICTRP records into CRS Web was temporarily suspended.

SELECTION CRITERIA

Randomized studies comparing any medication to placebo, another medication, or a behavioral intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality. We contacted study authors for additional data. We collected data on adverse events from the included trials.

MAIN RESULTS

We included three trials, with a total of 112 participants. Risk of bias was low for the included studies. Two pharmaceutical company-sponsored trials compared modafinil with placebo, involving 102 participants, nearly all of whom had idiopathic hypersomnia without long sleep time. Modafinil significantly improved self-reported sleepiness on the Epworth Sleepiness Scale by 5.08 points more than placebo (95% confidence interval (CI) 3.01 to 7.16; 2 studies, 101 participants; high-certainty evidence). Modafinil also significantly improved disease severity on the Clinical Global Impression of Severity scale by 1.02 points (95% CI 0.11 to 1.93; 1 study, 30 participants; moderate-certainty evidence) and resulted in a greater proportion of participants who were "much improved" or "very much improved" on the Clinical Global Impression of Change (odds ratio (OR) for improvement 5.14, 95% CI 1.76 to 15.00; 1 study, 70 participants; moderate-certainty evidence). Ability to remain awake on the Maintenance of Wakefulness Test was significantly improved with modafinil, by 4.74 minutes more than with placebo (95% CI 2.46 to 7.01; 2 studies, 99 participants; high-certainty evidence). Ratings of exhaustion and effectiveness/performance were improved with modafinil compared to placebo in one study. Number of naps per week was no different between modafinil and placebo across two studies. Participants receiving modafinil experienced more side effects, although the difference did not reach statistical significance (OR 1.68, 95% CI 0.28 to 9.94; 2 studies, 102 participants; low-certainty evidence). One trial studying 20 participants with different disorders of sleepiness included 10 participants with idiopathic hypersomnia, with or without long sleep time, and compared clarithromycin to placebo. We only included the subset of trial data for those participants with idiopathic hypersomnia, per our protocol. There were no significant differences between clarithromycin and placebo for the Epworth Sleepiness Scale, psychomotor vigilance testing, sleep inertia, other subjective ratings, or side effects.

AUTHORS' CONCLUSIONS

Modafinil is effective for the treatment of several aspects of idiopathic hypersomnia symptomatology, based on studies predominantly including participants with idiopathic hypersomnia without long sleep times, with low risk of bias, and evidence certainty ranging from high to low. There is insufficient evidence to conclude whether clarithromycin is effective for the treatment of idiopathic hypersomnia. There is a clear need for additional studies testing interventions for the treatment of idiopathic hypersomnia.