An open-label, randomized crossover study to evaluate the pharmacokinetics, bioavailability, bioequivalence, and food effect following administration of Oxybate Formulations in healthy subjects.

JZP-258 is a new investigational compound that may eventually be used for the
treatment of narcolepsy. Narcolepsy is a sleeping disorder that involves
excessive daytime sleepiness, and in some people, a sudden loss of muscle tone
usually triggered by strong emotion.
JZP-258 is an oral oxybate formulation that is being compared to Xyrem.

Primary Objectives:
Part 1:
To assess the relative bioavailability and bioequivalence of JZP-258 compared
with Xyrem oral solution under fasting and fed conditions.
To evaluate the pharmacokinetics (PK) of JZP-258 under fasting and fed
conditions (food effect).
Part 2:
To evaluate the relative bioavailability and bioequivalence of two admixtures
of JZP-258 and Xyrem at different ratios compared with Xyrem oral solution
under fasting conditions
To evaluate the pharmacokinetics (PK) of JZP-258 2.25 g under fasting conditions

Secondary Objective:
Part 1:
To assess the safety and tolerability of JZP-258 and Xyrem under fasting and
fed conditions.
Part 2:
To assess the safety and tolerability of two admixtures of JZP-258 and Xyrem at
different ratios under fasting conditions.

This study will be performed in a group of approximately 60 healthy male or
female volunteers.
The volunteers will receive 4 treatments in which either JZP-258 or Xyrem will
be administered with or without food.
Each period the volunteers will receive a solution of 4.5 g JZP-258 or Xyrem,
diluted in 60 mL of water, taken with 180 mL of tap water.
In Part 2, two admixtures of JZP-258 and Xyrem in different ratios will be
compared with Xyrem under fasting conditions. The PK of JZP-258 at a lower dose
of 2.25 g will also be evaluated under fasting conditions.

The study consists of 4 treatments in which either JZP-258 or Xyrem will be
administered with or without food. The order in which the volunteers will
receive the treatments will be determined by chance. Please refer to the table
below to see the planned treatments:

Part 1:
Treatment How often
A 4.5 g JZP-258 Once, 10 hours fasted
B 4.5 g JZP-258 Once, 10 hours fasted
C 4.5 g Xyrem Once, 10 hours fasted
D 4.5 g Xyrem Once, 10 hours fasted

Part 2:

E: Admixture of 4.5 g JZP-258 and Xyrem diluted in 60 mL of water, taken with
180 mL water, under fasting conditions
F: Admixture of 4.5 g JZP-258 and Xyrem diluted in 60 mL of water, taken with
180 mL water, under fasting conditions,
G: 4.5 g Xyrem, diluted in 60 mL of water, taken with 180 mL water, under
fasting conditions
H: 2.25 g JZP-258, diluted in 60 mL of water, taken with 180 mL (6 fluid
ounces) of water, under fasting conditions

During the study various examinations are carried out that can be experienced
more or less stressful.
Blood sampling, indwelling cannula, heart tracing (ECG), pulse oximetry