Effectiveness and tolerability in people with narcolepsy transitioning from sodium oxybate to low-sodium oxybate: Data from the real-world TENOR study

Impaired cognition in narcolepsy: clinical and neurobiological perspectives

In addition to well-known symptoms such as sleepiness and cataplexy, many people with narcolepsy have impaired cognition, reporting inattention, poor memory, and other concerns. Unfortunately, research on cognition in narcolepsy has been limited. Strong evidence demonstrates difficulties with sustained attention, but evidence for executive dysfunction and impaired memory is mixed. Animal research provides some insights into how loss of the orexin neurons in narcolepsy type 1 may give rise to impaired cognition via dysfunction of the prefrontal cortex, and cholinergic and monoaminergic systems. This paper reviews some of these clinical and preclinical findings, provides a neurobiological framework to understand these deficits, and highlights some of the many key unanswered questions.

Effectiveness and optimization of low-sodium oxybate in participants with narcolepsy switching from a high-sodium oxybate: data from the Substitution of Equal Grams of Uninterrupted Xyrem to Xywav study

STUDY OBJECTIVES

Low-sodium oxybate (LXB; calcium, magnesium, potassium, and sodium oxybates; Xywav) contains the same active moiety as high-sodium oxybates (SXBs; SXB [Xyrem] and fixed-dose SXB [Lumryz]), with 92% less sodium, and is approved in the United States for treatment of cataplexy or excessive daytime sleepiness in patients 7 years of age and older with narcolepsy, and idiopathic hypersomnia in adults. Patients with narcolepsy have increased cardiovascular risk relative to people without narcolepsy. LXB's lower sodium content is recognized by the United States Food and Drug Administration in the narcolepsy population as clinically meaningful in reducing cardiovascular morbidity compared with SXBs. The Substitution of Equal Grams of Uninterrupted Xyrem to Xywav study (NCT04794491) examined the transition experience of patients with narcolepsy switching from SXB to LXB.

METHODS

Eligible participants were aged 18-80 years with narcolepsy type 1 or 2 on a stable SXB dose/regimen. After 2 weeks, participants transitioned gram-per-gram to LXB for 6 weeks, with opportunity for subsequent titration. Assessments included the Epworth Sleepiness Scale, Patient Global Impression of change, Ease of Switching Medication Scale, and Forced Preference Questionnaire.

RESULTS

The study enrolled 62 participants at baseline; 60 transitioned to LXB and 54 completed the study. At baseline and end of the LXB intervention/early discontinuation, respectively, mean total doses were 8.0 and 8.0 g/night; mean Epworth Sleepiness Scale scores were 9.4 and 8.8. Most participants reported improvement (45%) or no change (48%) in narcolepsy symptoms on the Patient Global Impression of change, reported the transition to LXB was "easy" (easy, extremely easy, not difficult at all; 93%) on the Ease of Switching Medication Scale, and preferred LXB compared with SXB (79%) on the Forced Preference Questionnaire, most commonly due to the lower sodium content.

CONCLUSIONS

Most participants switched from SXB to LXB with minimal modifications of dose/regimen and reported the transition process was easy. Effectiveness of oxybate treatment was maintained on LXB, and most participants preferred LXB to SXB. No new safety or tolerability issues were identified.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: An Interventional Safety Switch Study (Segue Study) of XYWAV in Narcolepsy; URL: https://classic.clinicaltrials.gov/ct2/show/NCT04794491; Identifier: NCT04794491.

CITATION

Macfadden W, Leary EB, Fuller DS, Kirby MT, Roy A. Effectiveness and optimization of low-sodium oxybate in participants with narcolepsy switching from a high-sodium oxybate: data from the Substitution of Equal Grams of Uninterrupted Xyrem to Xywav study. J Clin Sleep Med. 2024;20(9):1467-1477.

Cardiovascular Risks in People With Narcolepsy: Expert Panel Consensus Recommendations

BACKGROUND

Observational and retrospective studies suggest that people with narcolepsy may have an increased prevalence of cardiovascular and cardiometabolic comorbidities and may be at greater risk for future cardiovascular events. An expert consensus panel was formed to establish agreement on the risk of hypertension and cardiovascular/cardiometabolic disease in people with narcolepsy and to develop strategies to mitigate these risks.

METHODS AND RESULTS

Experts in sleep medicine and cardiology were selected to participate in the panel. After reviewing the relevant literature, the experts identified key elements, drafted recommendation statements, and developed discussion points to provide supporting evidence for the recommendations. The draft and final recommendations were rated on a scale from 0 (not at all agree) to 4 (very much agree). All experts had an agreement rating of 4.0 for all 14 revised recommendation statements for patients with narcolepsy. These statements comprised 3 themes: (1) recognize the risk of hypertension and cardiovascular/cardiometabolic disease, (2) reduce the risk of hypertension and cardiovascular/cardiometabolic disease, and (3) reduce sodium intake to lower the risk of hypertension and cardiovascular disease.

CONCLUSIONS

These consensus recommendations are intended to increase awareness of potential cardiovascular/cardiometabolic risks in patients with narcolepsy for all clinicians. Early monitoring for, and prevention of, cardiovascular risks in this population are of great importance, especially as narcolepsy usually develops in adolescents and young adults, who will be exposed to adverse effects of the disease for decades. Prospective systematic studies are needed to determine association and causation of narcolepsy with cardiovascular/cardiometabolic disorders.

Dosing Optimization of Low-Sodium Oxybate in Narcolepsy and Idiopathic Hypersomnia in Adults: Consensus Recommendations

INTRODUCTION

Low-sodium oxybate (LXB) is approved for treatment of narcolepsy in patients aged 7 years and older and treatment of idiopathic hypersomnia in adults. LXB contains the same active moiety with 92% less sodium than sodium oxybate (SXB). As the indication for oxybate treatment in patients with idiopathic hypersomnia is new and allows for individualized dosing optimization, guidance for beginning LXB treatment is needed. In particular, clinicians may benefit from guidance regarding treatment initiation, dosing/regimen options, potential challenges, and treatment expectations. Additionally, pharmacokinetic profiles differ slightly between both treatments, and further guidance on transitioning from SXB to LXB in patients with narcolepsy may aid clinicians.

METHODS

An expert panel of five sleep specialists was convened to obtain consensus on recommendations for these topics using a modified Delphi process.

RESULTS

Across two virtual meetings, the panel agreed on 31 recommendations with a high degree of consensus that fell into four overarching topics: (1) introducing LXB to patients; (2) initiating LXB for adult narcolepsy and idiopathic hypersomnia; (3) addressing challenges in using LXB; and (4) transitioning from SXB to LXB. The panel recommended that clinicians provide a clear overview of how LXB works for treating symptoms in narcolepsy or idiopathic hypersomnia, as appropriate for their patients, explain safety aspects, and set expectations prior to initiating LXB treatment. Strategies for initial dosing and regimen are provided. Strategies for adjusting the dose, regimen, timing, and consideration of individual factors were developed for specific instances in which patients may have trouble staying asleep or waking up, as well as guidance for addressing potential adverse events, such as nausea, dizziness, anxiety, and depression. Discussion points based on existing literature and clinical experience were included as relevant for each statement.

CONCLUSION

Clinicians may use this resource to guide LXB dosing optimization with patients.

Is pitolisant safe for clinical use? A retrospective pharmacovigilance study focus on the post-marketing safety

Pitolisant, a novel histamine H3-receptor antagonist, holds significant promise for treating narcolepsy. However, a petition, which highlighted that pitolisant was associated with deaths during clinical trials, has propelled it into the spotlight of widespread societal attention on April 3, 2023. Till now, the clinical safety of pitolisant remains a heatedly debated topic. This study aimed to offer a comprehensive assessment of the safety profile of pitolisant in real-world clinical settings. Adverse event reports where pitolisant was the primary suspect drug were extracted from the FDA Adverse Event Reporting System database. The clinical characteristics and concomitant drugs of the pitolisant-associated adverse events were analyzed. The potential adverse event signals of pitolisant were explored using four disproportionality analysis methods. Furthermore, the difference in pitolisant-associated adverse event signals was investigated concerning sex, age, weight, and dose. A total of 526 reports and 1695 adverse events with pitolisant as the primary suspected drug were identified. The most significant adverse event signals were generally mild and of short duration. The concomitant drugs of pitolisant were highly intricate, mainly included drugs for treating narcolepsy as well as antidepressants. Seven new significant adverse event signals emerged. The safety profile of pitolisant exhibited no significant differences across age and dose groups, although slight variations were observed in relation to sex and weight. The findings from reports of death and life-threatening outcomes underscore the importance of enhanced monitoring for cardiac and respiratory adverse reactions when utilizing pitolisant. This study provided a broader understanding of the safety profile of pitolisant.