Real-world treatment of pediatric narcolepsy with pitolisant: A retrospective, multicenter study

Interim analysis of a post-authorization safety study of pitolisant in treating narcolepsy: A real-world European study

BACKGROUND

Narcolepsy is a chronic sleep disorder characterized mainly by excessive daytime sleepiness (EDS) and cataplexy in the case of narcolepsy type 1 (NT1). Pitolisant is a histamine 3 receptor antagonist/inverse agonist that reduces EDS and cataplexy in patients with narcolepsy.

METHODS

We performed a prospective 5-year follow-up, non-interventional study of adults with NT1 and NT2 receiving pitolisant. The primary objectives were to collect information on the long-term safety of pitolisant and analyze the utilization patterns of pitolisant. The secondary objectives were to assess clinical benefit, adherence, impact on patients' quality of life, disease burden, and patient satisfaction. We reported the results of an interim analysis after 42.6 months.

RESULTS

The population comprised 370 patients (mean age, 40 ± 15 years; 51.4 % women; NT1, 71.4 %; NT2, 28.6 %); 364 received ≥1 dose of pitolisant. Data were available for 356 patients (97.8 %). Most patients (68.4 %) had ≥1 comorbidity (obesity [BMI≥30], 31.9 %; neuropsychiatric, 31 %; and cardiovascular, 22.8 %). Forty-eight patients (13.2 %) had received no prior narcoleptic treatment, while 98 (31 %) were taking a previous therapy, which was switched to pitolisant. Treatment was combined with pitolisant in 218 (69 %) patients. Pitolisant was discontinued by 131 patients (35.4 %), mainly for safety reasons (14.3 %), lack of response (8.7 %), and patient decision (7.6 %). Overall, 355 treatment-emergent adverse events (3 serious) were reported by 156 patients (42.9 % of safety population), with 218 possibly treatment-related (61.4 %) in 109 patients (29.9 %). Improvements were observed in EDS, cataplexy, and quality of life.

CONCLUSIONS

Pitolisant was generally safe and well tolerated in patients with NT1 and NT2 and can be used in both types. Improvements were found in EDS, cataplexy, and quality of life, with good adherence and satisfaction.

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.

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.

Clinical Evaluation and Management of Narcolepsy in Children and Adolescents

While sleepiness is common among children, and particularly adolescents, profound sleepiness in the setting of apparently adequate sleep should prompt consideration of a central disorder of hypersomnolence. These disorders, which include narcolepsy, idiopathic hypersomnia, Kleine-Levin syndrome, and others, are likely underrecognized in the pediatric population. Narcolepsy in particular should be of interest to child neurologists as the unique signs and symptoms of this disease often prompt evaluation in pediatric neurology clinics. While sleepiness may appear to be a straightforward complaint, its evaluation requires a nuanced approach. Cataplexy, a hallmark of narcolepsy, can be confused for other neurologic conditions, though understanding its various manifestations makes it readily identifiable. Clinicians should be aware of these symptoms, as delay in diagnosis and misdiagnosis are common in childhood narcolepsy. While treatment options have been limited in the past, many new therapeutic options have become available and can result in significant improvement in symptoms. Given the age at presentation, paroxysmal and chronic features, diagnostic modalities, and available treatment options, the field of child neurology is well equipped to see patients with narcolepsy. In this review, I will focus on the presentation, evaluation, and management of pediatric patients with narcolepsy.