PRC-063 in an ADULT Workplace Environment

This is a randomized, double-blind, crossover, placebo-controlled, optimized-dose, phase 3
study to evaluate the safety and efficacy of PRC-063 (methylphenidate hydrochloride
controlled-release capsules 25, 35, 45, 55, 70, 85 or 100 mg/day) in the treatment of
Attention-Deficit/Hyperactivity Disorder (ADHD) in adult subjects greater than or equal to
18 years of age and less than or equal to 60 years of age. After giving written informed
consent, subjects will be screened to ascertain their suitability for the study according to
the inclusion and exclusion criteria. The study will have four phases: (1) Screening and
subsequent washout, if needed; (2) baseline and open-label dose optimization during which
subjects will be titrated from a starting dose of 25 mg up to his/her final dose (25, 35,
45, 55, 70, 85 or 100 mg/day); (3) AWE sessions 1 and 2 in the adult analog setting
following a practice session; and (4) 14-day safety follow-up. Subjects will be required to
visit the clinic up to 10 times over a 9-week period.

Inclusion Criteria:

- Must be male or non-pregnant female at least 18 years of age and less than or equal
to 60 years of age.

- Must have an ADHD diagnosis, in attentive, hyperactive/impulsive or combined, as
defined by the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition
(DSM-5) based on clinician assessment using multiple informants and a structured
interview.

- Clinician-completed ADHD-5-RS total score must be equal to or greater than 24, as
assessed at Visit 2a.

- Must be unsatisfied with his or her current pharmacological therapy for treatment of
ADHD or not currently receiving pharmacological therapy for ADHD. Inclusion of
subjects naïve to pharmacological therapy for ADHD is permitted.

- Female subjects must be one of the following: a. surgically sterile prior to
screening; b. if of childbearing potential, abstinent or willing to use a reliable
method of contraception, such as oral contraceptive, two barrier methods, a barrier
method plus a spermicidal agent.

- Female subjects of Child-Bearing Potential (FOCP) must be a negative serum β-hCG
pregnancy test at screening.

- Must have a minimum level of intellectual functioning, as determined by an
Intelligence Quotient (IQ) score of 80 or above based on the KBIT-2.

- Mentally and physically competent to sign an informed assent document, in the case of
the subject, and an informed consent document, in the case of the parent/guardian,
indicating that they understand the purpose of and procedures required for the study
and are willing to participate in the study.

- Able and willing to comply with the study procedures for the entire length of the
study, including a successful swallow test of an empty 100 mg capsule.

Exclusion Criteria:

- Having an allergy to methylphenidate or amphetamines or a history of serious adverse
reactions to methylphenidate.

- Known to be non-responsive to methylphenidate treatment. Non-response is defined as
methylphenidate use at various doses for a phase of at least four weeks at each dose
with little or no clinical benefit in the last 10 years.

- Being diagnosed with or having a history of strokes, epilepsy, migraine headaches
(greater than 1 instance every two months), glaucoma, thyrotoxicosis,
tachyarrhythmias or severe angina pectoris or have serious or unstable medical
illness. Subjects with controlled or stable asthma or diabetes will be permitted.

- Elevated blood pressure, defined as any values above 89 diastolic or 139 systolic, as
assessed at Visit 1.

- Clinically significant ECG abnormalities, as assessed at Visit 1.

- Clinically significant laboratory abnormalities, as assessed at Visit 1.

- Currently receiving guanethidine, pressor agents, MAO inhibitors, coumarin
anticoagulants, anticonvulsants (e.g., phenobarbital, phenytoin, primidone),
phenylbutazone, tricyclic antidepressants (e.g., imipramine, desipramine), selective
serotonin reuptake inhibitors (SSRIs) or herbal remedies (unless on a stable dose for
4 weeks).

- Subject has known history of symptomatic cardiovascular disease, advanced
arteriosclerosis, structural cardiac abnormality, cardiomyopathy, serious heart
rhythm abnormalities, coronary heart disease, transient ischemic attack or stroke or
other serious cardiac problems that may place the subject at increased vulnerability
to the sympathomimetic effects of a stimulant drug.

- Subject has a known family history of sudden cardiac death or ventricular arrhythmia.

- Subjects who are currently considered a suicide risk by the investigator.

- Having a primary diagnosis of schizophrenia, schizoaffective disorder, primary
affective disorder, schizotypal personality, major depression, bipolar disorder,
generalized anxiety, borderline personality disorder, antisocial personality or
another unstable psychiatric condition requiring treatment, as assessed by the
structured interview conducted at Visit 1.

- Having a history or suspected physiological dependence within the past 5 years
(excluding nicotine) on narcotic analgesics or other psychoactive drugs (including
barbiturates, opiates, cocaine, cannabinoids, amphetamines and benzodiazepines).

- Excessive consumption of alcohol (consumes alcohol in quantities greater than 15
drinks per week; 1 drink is defined as 360 mL/12 oz. of beer, 120 mL/4 oz. of wine,
or 30 mL/1 oz. of hard liquor), or history (within previous 6 months) of alcohol
abuse.

- Currently (or within 30 days before the planned start of treatment) receiving an
investigational drug or using an experimental medical device.

- Homeless.