Once-nightly sodium oxybate (FT218) demonstrated improvement of symptoms in a phase 3 randomized clinical trial in patients with narcolepsy

RESTORE: Once-nightly oxybate dosing preference and nocturnal experience with twice-nightly oxybates

Objective/Background

Preference for extended-release, once-nightly sodium oxybate (ON-SXB, FT218) vs twice-nightly immediate-release (IR) oxybate was assessed in participants switching from IR oxybate to ON-SXB in an open-label/switch study, RESTORE (NCT04451668).

Patients/Methods

Participants aged ≥16 years with narcolepsy who completed the phase 3 REST-ON trial, were oxybate-naive, or were on a stable IR oxybate dose (≥1 month) were eligible for RESTORE. For participants who switched from twice-nightly dosing to ON-SXB, initial doses were closest or equivalent to their previous nightly IR oxybate dose. These participants completed a questionnaire at baseline about nocturnal adverse events associated with the middle-of-the-night IR oxybate dose in the preceding 3 months, a preference questionnaire after 3 months of stable-dose ON-SXB, and an end-of-study (EOS) questionnaire.

Results

There were 130 switch participants; 92/98 (93.9 %) who completed the preference questionnaire preferred ON-SXB. At baseline, 69.2 % reported missing their second IR oxybate dose at least once; in these cases, 80 % felt worse the next day. Approximately 39 % reported taking a second nightly IR oxybate dose >4 h after the first dose, 51 % of whom felt somewhat to extremely groggy/unsteady the next morning; 120 participants (92 %) reported getting out of bed after their second oxybate dose. Of those, 9 (8 %) reported falls and 5 (4 %) reported injuries. Of the switch participants who completed the EOS questionnaire, 91.2 % felt better able to follow the recommended ON-SXB dosing schedule.

Conclusions

The second nightly IR oxybate dose presents significant treatment burdens and adherence concerns. Participants overwhelmingly preferred the once-nightly dosing regimen of ON-SXB.

Cataplexy response with extended-release once-nightly sodium oxybate: Post hoc responder analyses from the phase 3 REST-ON clinical trial

Background

Once-nightly sodium oxybate (ON-SXB), an extended-release oxybate formulation, yielded significant (P < 0.001 at 6 g, 7.5 g, and 9 g) reductions in cataplexy episodes in participants in the phase 3 REST-ON clinical trial (NCT02720744). This post hoc analysis from REST-ON further characterized changes in cataplexy episodes in participants with narcolepsy type 1 (NT1).

Methods

Participants with narcolepsy aged ≥16 years received ON-SXB (1 wk, 4.5 g; 2 wk, 6 g; 5 wk, 7.5 g; 5 wk, 9 g) or placebo. Percentages of participants with NT1 who had ≥25%, ≥50%, ≥75%, and 100% reductions from baseline in mean number of weekly cataplexy episodes were determined. Two-sided P values comparing ON-SXB vs placebo were calculated with Fisher exact test.

Results

Participants with NT1 (ON-SXB, n = 73; placebo, n = 72; modified intent-to-treat population) had a baseline mean number of weekly cataplexy episodes of 18.9 (ON-SXB) and 19.8 (placebo). Of participants receiving the highest doses of ON-SXB (7.5 and 9 g), approximately half had a 50% reduction, one-third had a 75% reduction, and one-tenth had a 100% reduction in their cataplexy episodes vs placebo. Significantly greater proportions of participants receiving ON-SXB vs placebo had respective reductions in weekly cataplexy episodes of ≥25% at weeks 1 (4.5 g; P < 0.05), 3 (6 g; P < 0.001), 8 (7.5 g; P < 0.001), and 13 (9 g; P = 0.001).

Conclusions

A significantly greater proportion of participants receiving ON-SXB vs placebo experienced reductions in weekly cataplexy episodes at all tested doses. Approximately 10% of participants taking the 2 highest ON-SXB doses had complete elimination of their cataplexy.

Improvement in sleep latency with extended-release once-nightly sodium oxybate for the treatment of adults with narcolepsy: Analysis from the phase 3 REST-ON clinical trial

Background

In the REST-ON clinical trial (NCT02720744), mean sleep latency on the Maintenance of Wakefulness Test (MWT) was significantly improved with extended-release once-nightly sodium oxybate (ON-SXB) vs placebo (P < 0.001) in participants with narcolepsy. This post hoc analysis assessed response to treatment and improvement in excessive daytime sleepiness.

Methods

Participants with narcolepsy aged ≥16 years were randomized 1:1 to receive ON-SXB (4.5 g, week 1; 6 g, weeks 2-3; 7.5 g, weeks 3-8; and 9 g, weeks 9-13) or placebo. Mean sleep latency on the MWT was measured across 5 trials of ≤30 min each. Post hoc assessments included percentage of participants whose sleep latency improved ≥5, ≥10, ≥15, and ≥20 min and with a mean sleep latency of 30 min.

Results

Significantly more participants receiving ON-SXB vs placebo experienced increased mean sleep latency ≥5 min (all doses P < 0.001), ≥10 min (all doses P < 0.001), ≥15 min (6 and 7.5 g, P < 0.001; 9 g, P < 0.01), and ≥20 min (6 g, P < 0.01; 7.5 g, P < 0.001; 9 g, P < 0.05). More participants receiving ON-SXB had mean sleep latency of 30 min vs placebo (6 g, 5.7 % vs 0 %, respectively [P < 0.05]; 7.5 g, 10.5 % vs 1.3 % [P < 0.05]; 9 g, 13.2 % vs 5.1 % [P = 0.143]).

Conclusions

Significantly more participants who received ON-SXB experienced increased mean sleep latency ≥5 to ≥20 min; at the 2 highest doses, >10 % remained awake for the entirety of the MWT. ON-SXB offers a once-at-bedtime treatment option for adults with narcolepsy.

Efficacy of once-nightly sodium oxybate (FT218) on daytime symptoms in individuals with narcolepsy with or without concomitant alerting agent use: A post hoc analysis from the phase 3 REST-ON trial

OBJECTIVE/BACKGROUND

Extended-release, once-nightly sodium oxybate (ON-SXB) significantly improved narcolepsy symptoms in participants in the phase 3, randomized, double-blind, placebo-controlled REST-ON trial. This post hoc analysis of REST-ON data evaluated ON-SXB efficacy in participants with or without concomitant alerting agent use.

PATIENTS/METHODS

Participants with narcolepsy aged >16 years were randomized 1:1 to ON-SXB (week 1: 4.5 g, weeks 2-3: 6 g, weeks 4-8: 7.5 g, weeks 9-13: 9 g) or placebo. Primary endpoints in this post hoc analysis included change from baseline in mean sleep latency on the Maintenance of Wakefulness Test (MWT), Clinical Global Impression-Improvement (CGI-I) rating, and number of weekly cataplexy episodes. The secondary endpoints were change from baseline in the Epworth Sleepiness Scale (ESS) score and in objective and subjective disrupted nighttime sleep parameters. Post hoc analyses assessed participants with and without alerting agent use across 6-, 7.5-, and 9-g doses.

RESULTS

In the modified intent-to-treat population, 119 (63 %) were (ON-SXB, n = 66; placebo, n = 53) and 71 (37 %) were not (ON-SXB, n = 31; placebo, n = 40) taking alerting agents. Regardless of alerting agent use, treatment with ON-SXB resulted in significant improvements vs placebo (all doses, P < 0.05) for MWT, CGI-I, and number of weekly cataplexy episodes. Significant improvements in ESS (all doses, P < 0.05) with ON-SXB vs placebo were observed in the alerting agent use cohort. Directional improvements in ESS were reported with all doses in the no alerting agent use group.

CONCLUSIONS

Regardless of concomitant alerting agent use, ON-SXB improved daytime and nighttime narcolepsy symptoms vs placebo.

Weight Loss With Once-nightly Sodium Oxybate for the Treatment of Narcolepsy: Analysis From the Phase III Randomized study Evaluating the efficacy and SafeTy of a ONce nightly formulation of sodium oxybate (REST-ON) Trial

PURPOSE

Individuals with narcolepsy are more likely to be obese than the general population. Changes in weight-related measures with extended-release, once-nightly sodium oxybate (ON-SXB) and characteristics of participants with ≥5% weight loss were assessed in a Randomized study Evaluating the efficacy and SafeTy of a ONce nightly formulation of sodium oxybate (REST-ON) trial post hoc analysis.

METHODS

REST-ON (NCT02720744) was a Phase III, double-blind, placebo-controlled, multicenter, randomized clinical trial. Participants aged ≥16 years with narcolepsy type 1 (NT1) or NT2 received ON-SXB or placebo for 13 weeks (week 1, 4.5 g; weeks 2-3, 6 g; weeks 4-8, 7.5 g; and weeks 9-13, 9 g). Weight and body mass index were measured at baseline and study end.

FINDINGS

Weights were similar between groups at baseline (mean [SD]; ON-SXB, 81.2 [20.8] kg; N = 107 [NT1, n = 80; NT2, n = 27]; placebo, 82.1 [22.5] kg; N = 105 [NT1, n = 82; NT2, n = 23]). At week 13 (9 g), mean (SD) weight decreased 1.3 (3.6) kg with ON-SXB and increased 0.2 (2.6) kg with placebo; 17.8% (19/107; NT1, n = 14; NT2, n = 5) of participants receiving ON-SXB had ≥5% weight loss versus 3.8% receiving placebo (4/105; NT1, n = 3; NT2, n = 1; P = 0.001). At week 13, least squares mean (SE) body mass index change from baseline was ‒0.51 (0.13) kg/m2 with ON-SXB and 0.08 (0.13) kg/m2 with placebo (least squares mean difference [95% CI], -0.59 [-0.95 to -0.23] kg/m2; P = 0.001). Excessive daytime sleepiness improved for both groups with ON-SXB, the ≥5% weight-loss subgroup exhibited larger improvement in the Maintenance of Wakefulness Test and Epworth Sleepiness Scale versus the other subgroup (weight loss <5%, no change, or weight gain) (Maintenance of Wakefulness Test, P = 0.019; Epworth Sleepiness Scale score, P < 0.001).

IMPLICATIONS

Narcolepsy is often associated with obesity, which may increase cardiometabolic risks. ON-SXB, an effective treatment for excessive daytime sleepiness and cataplexy, may be preferred in overweight or obese individuals to provide a more tailored treatment approach.

CLINICALTRIALS

GOV IDENTIFIER

NCT02720744.

Hits and misses with animal models of narcolepsy and the implications for drug discovery

INTRODUCTION

Narcolepsy is a chronic and rare neurological disorder characterized by disordered sleep. Based on animal models and further research in humans, the dysfunctional orexin system was identified as a contributing factor to the pathophysiology of narcolepsy. Animal models played a larger role in the discovery of some of the pharmacological agents with established benefit/risk profiles.

AREAS COVERED

In this review, the authors examine the phenotypes observed in animal models of narcolepsy and the characteristics of clinically used pharmacological agents in these animal models. Additionally, the authors compare the effects of clinically used pharmacological agents on the phenotypes in animal models with those observed in narcolepsy patients.

EXPERT OPINION

Research in canine and mouse models have linked narcolepsy to the O×R2mutation and orexin deficiency, leading to new diagnostic criteria and a drug development focus. Advancements in pharmacological therapies have significantly improved narcolepsy management, with insights from both clinical experience and from animal models having led to new treatments such as low sodium oxybate and solriamfetol. However, challenges persist in addressing symptoms beyond excessive daytime sleepiness and cataplexy, highlighting the need for further research, including the development of diurnal animal models to enhance understanding and treatment options for narcolepsy.

Effects of oxybate dose and regimen on disrupted nighttime sleep and sleep architecture

Many components of sleep are disrupted in patients with narcolepsy, including sleep quality, sleep architecture, and sleep stability (ie, frequent awakenings/arousals and frequent shifts from deeper to lighter stages of sleep). Sodium oxybate, dosed twice nightly, has historically been used to improve sleep, and subsequent daytime symptoms, in patients with narcolepsy. Recently, new formulations have been developed to address the high sodium content and twice-nightly dosing regimen of sodium oxybate: low-sodium oxybate and once-nightly sodium oxybate. To date, no head-to-head trials have been conducted to compare the effects of each oxybate product. This review aims to give an overview of the existing scientific literature regarding the impact of oxybate dose and regimen on sleep architecture and disrupted nighttime sleep in patients with narcolepsy. Evidence from 5 key clinical trials, as well as supporting evidence from additional studies, suggests that sodium oxybate, dosed once- and twice-nightly, is effective in improving sleep, measures of sleep architecture, and disrupted nighttime sleep in patients with narcolepsy. Direct comparison of available efficacy and safety data between oxybate products is complicated by differences in trial designs, outcomes assessed, and statistical analyses; future head-to-head trials are needed to better understand the advantage and disadvantages of each agent.

Implications of Oxybate Dosing Regimen for Sleep, Sleep Architecture, and Disrupted Nighttime Sleep in Patients with Narcolepsy: A Commentary

Narcolepsy is associated with disrupted nighttime sleep (DNS). Sodium oxybate (SXB; Xyrem®), administered twice nightly, is indicated for the treatment of cataplexy and excessive daytime sleepiness in patients 7 years or older with narcolepsy. Recently, low-sodium oxybate (LXB, Xywav®; for people 7 years of age and older), which contains 92% less sodium than SXB and is dosed twice nightly, and sodium oxybate for extended release (SXB-ER; Lumryz™; for adults), which contains equal sodium to SXB and is dosed once nightly, have also been approved to treat cataplexy or excessive daytime sleepiness in narcolepsy. This paper reviews the evidence regarding the overall impact of oxybate administration, and impact of different oxybate dosing regimens (once nightly, SXB-ER; twice nightly, SXB), on DNS in narcolepsy utilizing polysomnographic data from five clinical trials (three assessing SXB in adults [referred to here as SXB trials 1, 2, and 3], one assessing SXB in children [referred to as the pediatric SXB trial], and one assessing SXB-ER in adults [REST-ON]). Both once-nightly and twice-nightly oxybate regimens similarly improved symptoms of DNS. Regardless of dosing regimen, people with narcolepsy treated with oxybate experience roughly 42-53 arousals and 9-38 awakenings each night, with one of these awakenings on twice-nightly oxybate being due to the second dosing requirement in studies of SXB. Additionally, for SXB, but not SXB-ER, polysomnographic data has been analyzed by half of the night, demonstrating a greater positive impact on sleep architecture in the second half of the night, which might be related to its nonlinear pharmacokinetic profile. We conclude that while once-nightly and twice-nightly oxybate dosing regimens differ in their pharmacokinetic profiles, both improve DNS in patients with narcolepsy to a similar degree.

Efficacy of once-nightly sodium oxybate (FT218) in narcolepsy type 1 and type 2: post hoc analysis from the Phase 3 REST-ON Trial

STUDY OBJECTIVES

Post hoc analyses from the phase 3 REST-ON trial evaluated efficacy of extended-release once-nightly sodium oxybate (ON-SXB; FT218) vs placebo for daytime sleepiness and disrupted nighttime sleep in narcolepsy type 1 (NT1) and 2 (NT2).

METHODS

Participants were stratified by narcolepsy type and randomized 1:1 to ON-SXB (4.5 g, week 1; 6 g, weeks 2-3; 7.5 g, weeks 4-8; and 9 g, weeks 9-13) or placebo. Assessments included mean sleep latency on Maintenance of Wakefulness Test (MWT) and Clinical Global Impression-Improvement (CGI-I) rating (coprimary endpoints) and sleep stage shifts, nocturnal arousals, and patient-reported sleep quality, refreshing nature of sleep, and Epworth Sleepiness Scale (ESS) score (secondary endpoints) separately in NT1 and NT2 subgroups.

RESULTS

The modified intent-to-treat population comprised 190 participants (NT1, n = 145; NT2, n = 45). Significant improvements were demonstrated with ON-SXB vs placebo in sleep latency for NT1 (all doses, p < .001) and NT2 (6 and 9 g, p < .05) subgroups. Greater proportions of participants in both subgroups had CGI-I ratings of much/very much improved with ON-SXB vs placebo. Sleep stage shifts and sleep quality significantly improved in both subgroups (all doses vs placebo, p < .001). Significant improvements with all ON-SXB doses vs placebo in refreshing nature of sleep (p < .001), nocturnal arousals (p < .05), and ESS scores (p ≤ .001) were reported for NT1 with directional improvements for NT2.

CONCLUSIONS

Clinically meaningful improvements of a single ON-SXB bedtime dose were shown for daytime sleepiness and DNS in NT1 and NT2, with less power for the limited NT2 subgroup.

Narcolepsies, update in 2023

Narcolepsy type 1 (NT1) and type 2 (NT2), also known as narcolepsy with and without cataplexy, are sleep disorders that benefited from major scientific advances over the last two decades. NT1 is caused by the loss of hypothalamic neurons producing orexin/hypocretin, a neurotransmitter regulating sleep and wake, which can be measured in the cerebrospinal fluid (CSF). A low CSF level of hypocretin-1/orexin-A is a highly specific and sensitive biomarker, sufficient to diagnose NT1. Orexin-deficiency is responsible for the main NT1 symptoms: sleepiness, cataplexy, disrupted nocturnal sleep, sleep-related hallucinations, and sleep paralysis. In the absence of a lumbar puncture, the diagnosis is based on neurophysiological tests (nocturnal and diurnal) and the presence of the pathognomonic symptom cataplexy. In the revised version of the International Classification of sleep Disorders, 3rd edition (ICSD-3-TR), a sleep onset rapid eye movement sleep (REM) period (SOREMP) (i.e. rapid occurrence of REM sleep) during the previous polysomnography may replace the diurnal multiple sleep latency test, when clear-cut cataplexy is present. A nocturnal SOREMP is very specific but not sensitive enough, and the diagnosis of cataplexy is usually based on clinical interview. It is thus of crucial importance to define typical versus atypical cataplectic attacks, and a list of clinical features and related degrees of certainty is proposed in this paper (expert opinion). The time frame of at least three months of evolution of sleepiness to diagnose NT1 was removed in the ICSD-3-TR, when clear-cut cataplexy or orexin-deficiency are established. However, it was kept for NT2 diagnosis, a less well-characterized disorder with unknown clinical course and absence of biolo biomarkers; sleep deprivation, shift working and substances intake being major differential diagnoses. Treatment of narcolepsy is nowadays only symptomatic, but the upcoming arrival of non-peptide orexin receptor-2 agonists should be a revolution in the management of these rare sleep diseases.

Clinician Preferences for Oxybate Treatment for Narcolepsy: Survey and Discrete Choice Experiment

INTRODUCTION

Immediate-release sodium oxybate (SXB) has been Food and Drug Administration (FDA)-approved to treat narcolepsy since 2002; in 2020, a mixed-salt oxybates formulation was also approved. Both are taken at bedtime with a second dose taken 2.5-4 h later. A third oxybate option, an investigational extended-release SXB, may soon be available. This study was undertaken to understand clinicians' preferences between these 3 different oxybate treatments.

METHODS

Clinicians in active clinical practice for 3-35 years and experience treating patients with narcolepsy were recruited. A 30-min web-based survey quantified narcolepsy disease-state attitudes, treatment perceptions, and satisfaction with oxybates on 9-point scales. A discrete choice experiment (DCE) of 12 choice sets, with 2 hypothetical treatment profiles in each, was used to capture clinician preferences about overall oxybate therapy preference, impact on patient quality of life (QoL), and patient anxiety/stress. Attributes associated with current therapies and those expected to be available in the near future were included in the design.

RESULTS

The clinicians surveyed (n = 100) indicated that narcolepsy has a negative impact on patient QoL (mean rating, 7.7) and rated impact on QoL and treatment efficacy as the most important aspects of a narcolepsy treatment (mean rating, 7.3-7.7). Clinicians with experience prescribing oxybates had moderately high satisfaction with SXB and mixed-salt oxybates efficacy (mean ratings, 6.5-6.9) and safety (mean ratings, 6.1-6.7) and lower satisfaction with nightly dosing frequency (mean rating, 5.9 and 6.3, respectively). In the DCE, dosing frequency was the most important attribute driving overall product choice, patient QoL, and reducing patient anxiety/stress (relative attribute importance, 46.1, 41.7, and 44.0, respectively), with once nightly preferred over twice nightly.

CONCLUSION

Clinicians indicated a significantly higher preference for the once-at-bedtime dosing schedule versus twice nightly in selecting oxybate therapies overall and when aiming to improve patient QoL or reduce patient anxiety.

Calcium, magnesium, potassium, and sodium oxybates oral solution for cataplexy or excessive daytime sleepiness associated with narcolepsy

INTRODUCTION

Lower-sodium oxybate (LXB) is a novel formulation that is approved by the US Food and Drug Administration (FDA) to treat cataplexy and excessive daytime sleepiness (EDS) in adult patients and children ≥ 7 years with narcolepsy. LXB contains 92 percent less sodium than sodium oxybate (SXB), which adds 550-1640 mg of sodium/day at usual doses of 3-9 grams per day. The FDA has declared LXB to be clinically superior to SXB due to greater safety by reducing the chronic sodium load. Narcolepsy patients have high comorbidities for hypertension and cardiovascular disease, conditions which can be adversely affected by high sodium intake.

AREAS COVERED

This drug review discusses narcolepsy, current and upcoming pharmacotherapy, and LXB chemistry, pharmacodynamics, pharmacokinetics, and metabolism. Published results from LXB's phase 1 studies, a phase 3 study, and 2 post-marketing studies are reviewed. Databases searched included Pubmed, Google Scholar, Lexi-Comp, Scopus, Science, and Ovid.

EXPERT OPINION

LXB is efficacious in treating daytime sleepiness and cataplexy in adults and children ≥ 7 years with narcolepsy. Using LXB instead of SXB formulations may benefit narcolepsy patients with cardiovascular comorbidities and hypertension, but long-term studies are needed to prove it.

Long-Term Safety and Tolerability During a Clinical Trial and Open-Label Extension of Low-Sodium Oxybate in Participants with Narcolepsy with Cataplexy

BACKGROUND

The safety and efficacy of low-sodium oxybate (LXB; Xywav^®) were established in a randomized, double-blind, placebo-controlled, phase 3 withdrawal study in adults with narcolepsy with cataplexy; however, the longer-term safety profile has not yet been examined. The aim of the current analysis was to assess the time of onset and duration of common treatment-emergent adverse events (TEAEs) for LXB throughout the open-label optimized treatment and titration period (OLOTTP) and the stable dose period (SDP) portions of the main study, and the subsequent 24-week open-label extension (OLE).

METHODS

In a double-blind, placebo-controlled, randomized withdrawal trial of LXB, TEAEs were evaluated during the 12-week OLOTTP, the 2-week SDP, and the subsequent 24-week OLE. Eligible participants were aged 18-70 years with a diagnosis of narcolepsy with cataplexy. At study entry, participants were taking sodium oxybate (SXB) alone, SXB with other anticataplectics, other anticataplectics alone, or were anticataplectic-treatment naive; other anticataplectics were tapered and discontinued during the OLOTTP. All participants initiated LXB during week 1 of the OLOTTP, and their dose was individually titrated based on safety and efficacy. Following the main study period, participants entered the OLE after rescreening (re-entry) after discontinuing LXB treatment or directly after completing the main study (rollover). TEAEs were assessed in the safety population as of database lock. TEAE duration was defined as time from TEAE start date to end date (or end of SDP or OLE, if end date was unrecorded).

RESULTS

The safety population included 201 participants (SXB alone, n = 52; SXB with other anticataplectics, n = 23; other anticataplectics alone, n = 36; anticataplectic-treatment naive, n = 90). During the OLOTTP/SDP, headache was the most common LXB-emergent TEAE overall (71 events; n = 42 (21%); median (range) duration = 1 (1-147) day), followed by nausea (31 events; n = 26 (13%); median (range) duration = 9 (1-54) days) and dizziness (26 events; n = 21 (10%); median (range) duration = 7 (1-117) days). Among the 74 participants in the OLE, the most commonly reported TEAEs were headache (14 events; n = 7, 9%; peak incidence month 3 (n = 5/72); median (range) duration = 1 (1‒25) day), dizziness (8 events; n = 5, 7%; peak incidence month 1 (n = 3/74); median (range) duration = 26 (1‒181) days), and nasopharyngitis (6 events; n = 6, 8%; peak incidence month 6 (n = 2/69); median (range) duration = 9 (1‒24) days). Overall, study discontinuations attributed to TEAEs were 21/65 (32%) during the OLOTTP and SDP and 3/7 (43%) during the OLE.

CONCLUSIONS

In this long-term analysis, the safety and tolerability profile of LXB was generally consistent with the known safety profile of SXB. During the OLOTTP and SDP, most TEAEs occurred early and were generally of short duration. TEAE prevalence decreased throughout the duration of the OLE; the most common TEAEs reported during the OLE were headache, dizziness, and nasopharyngitis.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT03030599 (25 January 2017).

Comparative Efficacy and Safety of Multiple Wake-Promoting Agents for the Treatment of Excessive Daytime Sleepiness in Narcolepsy: A Network Meta-Analysis

Purpose

Narcolepsy is a rare debilitating disorder for which multiple novel pharmacological options have been approved as treatment for the past few years. The current study systematically updates the comparative efficacy and detailed safety analysis of approved wake-promoting agents in narcolepsy.

Methods

Randomized controlled trials (RCTs) were searched for diagnosed narcolepsy with approved interventions. Efficacy outcomes included the Maintenance of Wakefulness Test (MWT), Epworth Sleepiness Scale (ESS), Clinical Global Impression of Change (CGI-C), and Patient Global Impression of Change (PGI-C). Safety outcomes including overall adverse event (AE) risk were measured. The study was registered at PROSPERO (CRD 42022334915).

Results

The final analysis included 17 RCTs with five drug treatments: modafinil/armodafinil, sodium oxybate, pitolisant, solriamfetol, and lower-sodium oxybate (LXB). For efficacy measures, interventions included in each outcome were effective compared with placebo. Furthermore, the magnitude of solriamfetol effect on MWT (9.11 minutes; 95% CI=7.05-11.16), ESS (-4.79; 95% CI=-6.56 to -3.01), and PGI-C (9.39; 95% CI= 2.37-37.19), and LXB effect on CGI-C (9.67; 95% CI=2.73-34.26) was greater than that of other treatments included in each outcome compared with placebo. For safety measures, all interventions had an acceptable safety profile with LXB having least risk for overall AEs (0.56; 95% CI=0.20-1.53), serious AEs (0.33; 95% CI=0.09-1.20), AEs leading to treatment discontinuation (0.11; 95% CI=0.01-2.04), and all-cause discontinuation (0.04; 95% CI=0.00-0.67) compared to placebo. Placebo had the lowest risk for exploratory AEs.

Conclusion

All approved interventions were effective in controlling the symptoms of narcolepsy at varying degrees with an acceptable safety profile.

Randomized, crossover, open-label study of the relative bioavailability and safety of FT218, a once-nightly sodium oxybate formulation: Phase 1 study in healthy volunteers

OBJECTIVES

Treatment for narcolepsy with sodium oxybate (SXB) has required twice-nightly dosing, at bedtime and 2.5-4 h later. This study evaluated the pharmacokinetics of FT218, an investigational, extended-release, once-nightly formulation of SXB (ON-SXB), vs twice-nightly SXB.

METHODS

In this phase 1, open-label study, healthy volunteers were randomized (1:1) to ON-SXB 6 g or twice-nightly SXB (two 3-g doses administered 4 h apart); minimum 3-day washout before crossover. Doses were administered 2 h post-evening meal. Blood samples for pharmacokinetic assessments were collected predose and up to 14 h after the first dose during each treatment period.

RESULTS

Twenty-eight participants were enrolled (mean age, 39.6 years; 54% women; 93% white). Mean ± SEM area under the concentration-time curve for ON-SXB was 282.7 ± 30.2  μg·h/mL vs 273.3 ± 27.8 μg·h/mL for twice-nightly SXB. Geometric mean ratio (GMR; 90% CI) was 102.9 (98.0-108.0). Maximum γ-hydroxybutyrate (GHB) plasma concentration (C_max) was 65.8 ± 4.0 μg/mL for ON-SXB vs 77.1 ± 4.9 μg/mL for twice-nightly SXB (GMR [90% CI], 88.3 [80.5-97.0]). The GMR (90% CI) for GHB plasma concentrations 8 h post dose (C_8h) for ON-SXB vs twice-nightly SXB was 61.7 (45.8-83.0). The most frequently reported adverse events were the same for ON-SXB and twice-nightly SXB (nausea, dizziness, somnolence, vomiting).

CONCLUSIONS

GHB exposure and C_max with one 6-g dose of ON-SXB were bioequivalent to those with two 3-g doses of twice-nightly SXB, whereas C_8h was lower with ON-SXB. If approved, ON-SXB will provide a single bedtime oxybate option, with clinically relevant pharmacologic exposure during the entire sleep period.

Understanding and approaching excessive daytime sleepiness

Excessive daytime sleepiness (EDS) is a public health issue. However, it remains largely undervalued, scarcely diagnosed, and poorly supported. Variations in the definition of EDS and limitations in clinical assessment lead to difficulties in its epidemiological study, but the relevance of this symptom from a socioeconomic perspective is inarguable. EDS might be a consequence of several behavioural issues leading to insufficient or disrupted sleep, as well as a consequence of sleep disorders including sleep apnoea syndrome, circadian disorders, central hypersomnolence disorders (narcolepsy and idiopathic hypersomnia), other medical or psychiatric conditions, or medications. Furthermore, EDS can have implications for health as it is thought to act as a risk factor for other conditions, such as cardiovascular and neurodegenerative disorders. Because of the heterogeneous causes of EDS and the complexity of its pathophysiology, management will largely depend on the cause, with the final aim of making treatment specific to the individual using precision medicine and personalised medicine.

What respiratory physicians should know about narcolepsy and other hypersomnias

Narcolepsy and related central disorders of hypersomnolence may present to the sleep clinic with excessive daytime sleepiness. A strong clinical suspicion and awareness of the diagnostic clues, such as cataplexy, are essential to avoid unnecessary diagnostic delay. This review provides an overview of the epidemiology, pathophysiology, clinical features, diagnostic criteria and management of narcolepsy and related disorders, including idiopathic hypersomnia, Kleine-Levin syndrome (recurrent episodic hypersomnia) and secondary central disorders of hypersomnolence.

50th anniversary of the ESRS in 2022-JSR special issue

This article addresses the clinical presentation, diagnosis, pathophysiology and management of narcolepsy type 1 and 2, with a focus on recent findings. A low level of hypocretin-1/orexin-A in the cerebrospinal fluid is sufficient to diagnose narcolepsy type 1, being a highly specific and sensitive biomarker, and the irreversible loss of hypocretin neurons is responsible for the main symptoms of the disease: sleepiness, cataplexy, sleep-related hallucinations and paralysis, and disrupted nocturnal sleep. The process responsible for the destruction of hypocretin neurons is highly suspected to be autoimmune, or dysimmune. Over the last two decades, remarkable progress has been made for the understanding of these mechanisms that were made possible with the development of new techniques. Conversely, narcolepsy type 2 is a less well-defined disorder, with a variable phenotype and evolution, and few reliable biomarkers discovered so far. There is a dearth of knowledge about this disorder, and its aetiology remains unclear and needs to be further explored. Treatment of narcolepsy is still nowadays only symptomatic, targeting sleepiness, cataplexy and disrupted nocturnal sleep. However, new psychostimulants have been recently developed, and the upcoming arrival of non-peptide hypocretin receptor-2 agonists should be a revolution in the management of this rare sleep disease, and maybe also for disorders beyond narcolepsy.

Effect of FT218, a Once-Nightly Sodium Oxybate Formulation, on Disrupted Nighttime Sleep in Patients with Narcolepsy: Results from the Randomized Phase III REST-ON Trial

BACKGROUND

Sodium oxybate has been recognized as a gold standard for the treatment of disrupted nighttime sleep due to narcolepsy. Its short half-life and immediate-release formulation require patients to awaken 2.5-4 h after their bedtime dose to take a second dose. A novel extended-release, once-nightly sodium oxybate formulation (ON-SXB; FT218) is under US Food and Drug Administration review for the treatment of adults with narcolepsy.

OBJECTIVE

A phase III trial of ON-SXB in individuals with narcolepsy type 1 (NT1) or 2 (NT2) [the REST-ON trial; NCT02720744] has been conducted and the primary results reported elsewhere. Secondary objectives from REST-ON were to assess the efficacy of ON-SXB on disrupted nighttime sleep; the results of this analysis are reported here.

METHODS

In the double-blind, phase III REST-ON trial, patients aged ≥ 16 years were randomly assigned 1:1 to ON-SXB (1 week, 4.5 g; 2 weeks, 6 g; 5 weeks, 7.5 g; 5 weeks, 9 g) or placebo. Secondary endpoints included polysomnographic measures of sleep stage shifts and nocturnal arousals and patient-reported assessments of sleep quality and refreshing nature of sleep at 6, 7.5, and 9 g; post hoc analyses included changes in time spent in each sleep stage, delta power, and assessments in stimulant-use subgroups for prespecified endpoints.

RESULTS

In total, 190 participants (n = 97, ON-SXB; n = 93, placebo) were included in the efficacy analyses. All three ON-SXB doses demonstrated a clinically meaningful, statistically significant decrease vs placebo in the number of transitions to wake/N1 from N1, N2, and rapid eye movement (REM) stages (all doses p < 0.001) and the number of nocturnal arousals (p < 0.05 ON-SXB 6 g; p < 0.001 7.5 and 9 g). Sleep quality and refreshing nature of sleep were significantly improved with all three ON-SXB doses vs placebo (p < 0.001). Post hoc analyses revealed a significant reduction in time spent in N1 (p < 0.05 ON-SXB 6 g; p < 0.001 7.5 and 9 g) and REM (all p < 0.001) and increased time spent in N3 with ON-SXB vs placebo (all p < 0.001), with a significant increase in delta power (p < 0.01 ON-SXB 6 g; p < 0.05 7.5 g; p < 0.001 9 g) and increased REM latency (ON-SXB 7.5 g vs placebo; p < 0.05). Significant improvements in disrupted nighttime sleep were observed regardless of concomitant stimulant use.

CONCLUSIONS

The clinically beneficial, single nighttime dose of ON-SXB significantly improved disrupted nighttime sleep in patients with narcolepsy.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT02720744.

Calcium, Magnesium, Potassium, and Sodium Oxybates Oral Solution: A Lower-Sodium Alternative for Cataplexy or Excessive Daytime Sleepiness Associated with Narcolepsy

Lower-sodium oxybate (LXB) is an oxybate medication approved to treat cataplexy or excessive daytime sleepiness (EDS) in patients with narcolepsy 7 years of age and older in the United States. LXB was developed as an alternative to sodium oxybate (SXB), because the incidence of cardiovascular comorbidities is higher in patients with narcolepsy and there is an elevated cardiovascular risk associated with high sodium consumption. LXB has a unique formulation of calcium, magnesium, potassium, and sodium ions, containing 92% less sodium than SXB. Whereas the active oxybate moiety is the same for LXB and SXB, their pharmacokinetic profiles are not bioequivalent; therefore, a phase 3 trial in participants with narcolepsy was conducted for LXB. This review summarizes the background on oxybate as a therapeutic agent and its potential mechanism of action on the gamma-aminobutyric acid type B (GABA_B) receptor at noradrenergic and dopaminergic neurons, as well as at thalamocortical neurons. The rationale leading to the development of LXB as a lower-sodium alternative to SXB and the key efficacy and safety data supporting its approval for both adult and pediatric patients with narcolepsy are also discussed. LXB was approved in August 2021 in the United States for the treatment of idiopathic hypersomnia in adults. Potential future developments in the field of oxybate medications may include novel formulations and expanded indications for other diseases.

Preferences for Attributes of Sodium Oxybate Treatment: A Discrete Choice Experiment in Patients with Narcolepsy

PURPOSE

Current US FDA-approved treatments for narcolepsy include sodium oxybate (SXB) and calcium, magnesium, potassium, and sodium oxybates (mixed-salt oxybates), which require 2 nightly doses, 1 at bedtime and another 2.5 to 4 hours later. Once-nightly SXB (ON-SXB; FT218) is under FDA review to treat adults with narcolepsy. This study quantitatively characterized attributes of SXB treatment preferred by individuals with narcolepsy via a discrete choice experiment (DCE) and evaluated preferences for the product profiles of once-nightly vs twice-nightly SXB treatment.

PATIENTS AND METHODS

Adults with self-reported physician-diagnosed narcolepsy for ≥1 year and current or prior twice-nightly SXB treatment were eligible for this 30-minute, web-based study capturing patient experiences and a DCE. Participants responded to a survey instrument using 9-point scales; higher scores indicated greater severity/preference/satisfaction. In the DCE, hundreds of profiles were generated, each combining attributes of twice-nightly SXB and ON-SXB based on clinical trial data. The DCE was analyzed using a hierarchical Bayesian model.

RESULTS

Seventy-five participants were surveyed (50 current and 25 past twice-nightly SXB users). Dosing frequency was the most important attribute of SXB treatment; once nightly was significantly preferred vs twice nightly. The most common reasons for overall product preference were lack of need to wake up in the middle of the night for a second dose (48%), fewer side effects (46%), and ease of administration (32%). Number of nightly doses was the most important driver of taking the medication exactly as directed and reduced anxiety/stress. Participants were significantly more likely to prefer the blinded product profile of once-nightly SXB over twice-nightly SXB (mean rating, 7.5 vs 4.3; P<0.05).

CONCLUSION

Among the choices presented, dosing frequency was the most important attribute for overall product choice, likelihood to take medication exactly as directed, and reducing anxiety/stress. The ON-SXB blinded profile was significantly preferred over twice-nightly SXB.