World Narcolepsy Day 2021: Roundup of Recent Therapeutic Progress

World Narcolepsy Day 2021, which takes place on September 22, is a day dedicated towards raising awareness of narcolepsy on a global scale. Established by 28 patient advocacy organizations across 6 continents in 2019, World Narcolepsy Day unites the international narcolepsy community to inspire action, increase public knowledge, and elevate the voices of those dealing with narcolepsy worldwide.

It is estimated that anywhere from 135,000 to 200,000 people in the US have narcolepsy; however, since this condition often goes diagnosed, the number may be higher.¹ Symptoms of narcolepsy include excessive daytime sleepiness, sleep attacks, cataplexy, sleep paralysis, hallucinations, and disrupted nighttime sleep.

In an effort to continue to raise awareness, NeurologyLive rounded up some of the most notable and recent coverage of news within the field of narcolepsy care. This includes advancements in drug development, the understanding of the disease, and new ways of monitoring its progression.

FT218 Continues to Show Potential for Narcolepsy Treatment

FT218 (Avadel Pharmaceuticals), an investigational once-nightly sodium oxybate formulation, continued to show its ability as a potential treatment or narcolepsy in the phase 3 REST-ON study (NCT02720744).² Patients with narcolepsy in the trial demonstrated significant improvements in sleep latency, cataplexy attacks, and on Clinical Global Impression-Improvement scores. The drug is currently under review by the FDA after the agency accepted its new drug application in March, with a Prescription Drug User Fee Act (PDUFA) action date of October 15, 2021.³

FDA Approves Xywav for Idiopathic Hypersomnia

After years of only off-label, wake-promoting therapies available for use, the FDA approved the first treatment for idiopathic hypersomnia, JZP-258 (Xywav; Jazz Pharmaceutical). The combination agent of calcium, magnesium, potassium, and sodium oxybates will be available to patients in the fourth quarter of 2021 following Risk Evaluation and Mitigation Strategies implementation.⁴

Pediatric Narcolepsy Severity Scale Shows Promise as a Clinical Tool

A newly developed version of the Narcolepsy Severity Scale, dubbed the pediatric Narcolepsy Severity Scale, was found to be a useful clinical tool associated with self-reported sleepiness, insomnia, and depressive symptoms among school-aged children and adolescents with narcolepsy type 1.⁵ The easy administration and sensitivity of the tool to detect symptom changes after treatment ensures its future in clinical and research settings.

GHB as a GABA Receptor Agonist for Narcolepsy Therapy

In the August 2021 issue, Jennifer S. Sun, PhD, discusses the underlying mechanisms of narcolepsy, and why the most important inhibitory neurotransmitter of the mammalian central nervous system is y-aminobutyric acid (GABA), which can promote feelings of happiness and sedation.⁶ She also discusses y-Hydroxybutyrate, known as GHB or oxybate, which is a physiological compound present in the human body as both a precursor and degradation product of GABA.

Solriamfetol Efficacious, Easily Treated in Patients Initiating Treatment for Narcolepsy

Solriamfetol (Sunosi; Jazz Pharmaceuticals), a dopamine/norepinephrine reuptake inhibitor approved to treat excessive daytime sleepiness in adults with narcolepsy or obstructive sleep apnea, continued to show its efficacy among those switching narcolepsy medications.⁷ The START study consisted of a quantitative retrospective patient chart review among US-based physicians prescribing solriamfetol de novo, in transition from, or in addition to existing medications.

Saffron Supplementation Enhances Sleep for Adults With Unsatisfactory Sleep

A 3-arm, parallel group, randomized, double-blind, placebo-controlled trial found saffron extract (Affron; Gencor) to have sleep-enhancing effects on adults with unsatisfactory sleep. Additionally, saffron supplementation improved several outcome measures, namely sleep quality ratings, mood ratings after awakening, Insomnia Symptom Questionnaire (ISQ) score, and ISQ-insomnia classifications, when compared to placebo.⁸

REFERENCES
1. What is narcolepsy? National Institutes of Health. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Narcolepsy-Fact-Sheet. Updated September 3, 2020. Accessed September 21, 2021.
2. Kushida CA, Shapiro CM, Roth T, et al. Once-nightly sodium oxybate (FT218) demonstrated improvements of symptoms in a phase 3 randomized clinical trial in patients with narcolepsy. SLEEP. Published online August 6, 2021. doi:10.1093/sleep/zsab200
3. Avadel presents new clinical data from pivotal phase 3 REST-ON trial supporting clinical benefit of FT218 in patients with narcolepsy at SLEEP 2021. News release. Avadel Pharmaceuticals. June 9, 2021. Accessed September 21, 2021. https://www.globenewswire.com/news-release/2021/06/09/2244435/0/en/Avadel-Presents-New-Clinical-Data-from-Pivotal-Phase-3-REST-ON-Trial-Supporting-Clinical-Benefit-of-FT218-in-Patients-with-Narcolepsy-at-SLEEP-2021.html
4. Jazz Pharmaceuticals Announces U.S. FDA Approval of Xywav® (calcium, magnesium, potassium, and sodium oxybates) Oral Solution for Idiopathic Hypersomnia in Adults. News release. Jazz Pharmaceuticals. August 12, 2021. Accessed September 21, 2021. https://www.prnewswire.com/news-releases/jazz-pharmaceuticals-announces-us-fda-approval-of-xywav-calcium-magnesium-potassium-and-sodium-oxybates-oral-solution-for-idiopathic-hypersomnia-in-adults-301354616.html
5. Barateau L, Lcendreux M, Chenini S, et al. Measurement of Narcolepsy Symptoms in School-Aged Children and Adolescents: The Pediatric Narcolepsy Severity Scale. Neurology. Published online May 24, 2021. doi:10.1212/WNL.0000000000012272
6. Bowery, N. G. & Smart, T. G. GABA and glycine as neurotransmitters: a brief history. Br J Pharmacol. 147, S109–S119 (2006).
7. Jazz Pharmaceuticals Presents 18 Abstracts in Sleep Medicine at SLEEP 2021. News release. Jaz Pharmaceuticals. June 9, 2021. Accessed September 21, 2021. https://www.prnewswire.com/news-releases/jazz-pharmaceuticals-presents-18-abstracts-in-sleep-medicine-at-sleep-2021-301308898.html
8. Lopresti AL, Smith SJ, Drummond PD. An investigation into an evening intake of a saffron extract (affron®) on sleep quality, cortisol, and melatonin concentrations in adults with poor sleep: a randomised, double-blind, placebo-controlled, multi-dose study. Sleep Med. Published online August 11, 2021. doi:10.1016/j.sleep.2021.08.001