01 Jun Therapies available on the PBS for Narcolepsy
The following article is an edited excerpt from ASA’s Submission 16 for the inquiry into approval processes for new drugs and novel medical technologies in Australia.
Dr. Sheila Sivam, Dr. Ksenia Chamula, Dr. Simon Frenkel, A/Prof. Sutapa Mukherjee, Dr. John Swieca and Prof. Bandana Saini, on behalf of the Australasian Sleep Association.
Australian clinicians and narcolepsy patient groups have repeatedly voiced concerns about the inability to access many recommended first-line agents available to patients in other first-class health systems.
Narcolepsy types I and 2 are rare neurological disorders characterised by an irrepressible need to sleep, or daytime lapses into sleep. Both disorders are associated with abnormal nocturnal sleep, such as fragmented sleep, hypnagogic hallucinations and sleep paralysis episodes. Investigation findings for both disorders include a Multiple Sleep Latency Test demonstrating a daytime mean sleep latency of less than 8 minutes, with two sleep-onset rapid eye movement sleep periods. Type 1 narcolepsy is accompanied by cataplexy, a sudden onset loss of muscle tone with retained consciousness precipitated by strong emotions. The underlying pathology of type 1 narcolepsy is loss of the neurotransmitter hypocretin (also known as orexin) from the hypothalamus, either due to dysfunction or damage of neurons.
The most debilitating symptom in these disorders is daytime somnolence. Patients with narcolepsy experience reduced health-related quality of life. The prevalence of type 1 narcolepsy lies between 25 and 50 per 100,000 people. However, the prevalence of narcolepsy in Australia is not known.
The management of narcolepsy focuses on reducing excessive daytime sleepiness (EDS), aiming for maximal return to normal function, treating cataplexy, minimising overnight sleep disruption, sleep-related hallucinations and sleep paralysis.
In Australia, there are two classes of drugs available to reduce EDS on the Pharmaceutical Benefits Scheme (PBS): wakefulness promoters (modafinil and armodafinil) and stimulants (dexamfetamine). The PBS only allows access to wakefulness promoters, via the Complex Drugs Program, if dexamfetamine poses an unacceptable medical risk to the patient or has resulted in intolerance. This PBS restriction places, in effect, dexamfetamine as the first available option for treatment of narcolepsy related EDS in Australia, unlike in other first-class health systems, where stimulants such as dexamfetamine are used as second or even third-line agents.
AASM practice parameters published in 2007 listed only modafinil and sodium oxybate as ‘Standard’ level recommendations for the treatment of narcolepsy. Dexamphetamine and methylphenidate were listed as ‘Guideline’ recommendations, reflecting lower levels of evidence for their usage. Between 2016 and 2020, two other drugs have been approved for use in narcolepsy by both the FDA and the EMA: pitolisant and solriamfetol (dopamine and noradrenaline reuptake inhibitor).
Australia needs to re-examine the issue of access to drugs in diseases that are clinically recognised but rare, such that access is at par with other developed countries that may follow different models of health care. Improved processes for allowing Australian patients timely access to contemporary treatments are vital, to ensure equity in obtaining care, for these often challenging disorders. Improved alignment with international registration and reimbursement processes will be the key to modernising narcolepsy care in Australia.