A randomized, double-blind, crossover taste testing study in healthy subjects comparing JZP-258 and placebo.

JZP-258 is a new compound that is being tested in other studies for the
treatment of narcolepsy. Narcolepsy is defined as a rapid eye movement sleep
disorder resulting for the dysregulation of the sleep-wake cycle. Symptoms
include periods of excessive daytime sleepiness that may last from seconds to
minutes and may occur at any time. Other symptoms are sudden loss of muscle
strength, inability to move or hallucinations.

JZP-258 is a combination of 4 oxybate salts: sodium oxybate, potassium oxybate,
calcium oxybate, and magnesium oxybate. A similar compound with sodium oxybate
as the active compound (called Xyrem*) is already on the market for more than
10 years. Sodium oxybate is also known as the sodium salt of
gamma-hydroxybutyric acid (GHB).

Sodium oxybate is a substance that has respiratory depressant (slowing
breathing rate) or sedating effects in people. Xyrem® is an oral solution that
contains a lot of sodium. When taking a maximum dose of 9 gram per night, the
amount of sodium exceeds the allowable daily intake. By combining different
oxybate salts, the amount of daily intake of sodium will be reduced.

The purpose of this study is to compare the taste of JZP-258 to placebo (a
medicine without any active ingredient or fake medicine) for sameness. This is
to ensure that when used in other studies, subjects will not taste a difference
between both compounds.

The volunteers will stay in the research center in Groningen (UMCG) for 3 days
(2 nights).

Day 1 is the day of taste testing of the study compound. The volunteers are
expected at the research center at 14:00 h in the afternoon prior to the day of
tasting the study compound (Day -1). They will leave the research center on Day
2 of the study.

JZP-258 and placebo will be prepared as an oral solution. The volunteers will
be asked to taste the amount of 30 mL of the solution (pour liquid into your
mouth, assess the taste, and spit it back to the vial). They only need to
taste, they must not swallow the compound. The volunteers will have to taste 2
solutions 4 times (i.e. one pair of solutions each time) on one day (Day 1).
Each time, they will be asked to compare one pair of solutions. There are 3
different pairs of solutions that will be compared, these are:
- Pair 1: JZP-258 and JZP-258
- Pair 2: JZP-258 and placebo
- Pair 3: placebo and JZP-258
They will receive Pair 1 2 times, Pair 2 once, and Pair 3 once. This means that
overall, they will receive JZP-258 6 times and placebo 2 times.

Not applicable.

Pain, minor bleedings, bruises and possibly an infection.