Narcolepsy is characterized by symptoms such as excessive daytime sleepiness, cataplexy (sudden loss of muscle control, often triggered by strong emotions) and fragmented sleep. Narcolepsy occurs throughout the world but occurrence rates vary among populations. Occurrence of Narcolepsy is estimated to be 1 in 2,000 people in the United States and it affects around 3 million people worldwide, as reported in many epidemiology based studies. The occurrence rate of narcolepsy is remarkably lower in Israel and quite higher in Japan compared to the United States and Europe. In Europe, the occurrence rate is found to be higher in UK and Germany than other European countries. Most studies suggest that around 70% of narcolepsy cases remain undiagnosed and untreated.
Hypocretin (Orexin), produced by the special cells in the brain is important for regulating the Sleep/Wake Cycle. The death of these special cells leads to the complications of Narcolepsy. As these cells have not yet been possible to replace, the only way to treat Narcolepsy is to relieve the symptoms. The symptoms like Sleep/Wake Irregularities and REM (Rapid Eye movement) Intrusion can be treated by using modern medications and Lifestyle adjustments. Common medications for treating symptoms of narcolepsy include stimulants (Provigil), Sodium oxybate (Xyrem) and Antidepressants (Selective serotonin reuptake inhibitors such as Prozac, Zoloft and newer antidepressants Effexor. Sodium oxybate (Xyrem) is highly effective in treating cataplexy along with few Selective serotonin reuptake inhibitors (SSRIs).
PROVIGIL by Cephalon and XYREM by Jazz Pharmaceuticals are the top selling drugs capturing the majority of the market for Narcolepsy. Other drugs are also being used for the treatment of narcolepsy as the secondary indication, but do not have much impact on the overall market size. As per our estimation, more than 85% of total global market share will be covered by the United States by 2023. The Annual Cost of Therapy (ACOT) of Xyrem in the United States is quite higher than that in Europe. The US has the highest share in Narcolepsy space among major markets, mainly owing to higher ACOT of Xyrem. The market in Europe is estimated to be increasing and largely depends on the sales of PROVIGIL (modafinil) and XYREM (sodium oxybate) which are majorly contributing to the total European market. The upcoming pipeline drugs JZP-110 and FT218 are expected to be launched in 2017 and 2018, respectively. These drugs are expected to have a major impact on the market in the coming years. For Japan, the market scenario is quite different to that of Europe and US as both Provigil and Xyrem are not marketed in Japan. Basically, the market size in Japan is largely depending on the sales of the other drugs that are used as secondary treatment options for Narcolepsy. As per our analyses, the Narcolepsy market in Japan is expected to remain stable; however, a nominal decline can be seen by the year 2023, owing to the decrease in overall population.