Vigabatrin for the Treatment of Cocaine Dependency

The objective of this 26-28 week study is to demonstrate that the rate of cocaine dependent
subjects treated with CPP-109 vigabatrin in addition to counseling, who completely stop use
of cocaine in the last 2 weeks of the study's Treatment Phase (Weeks 8 and 9) will be higher
than seen in subjects treated with placebo in addition to counseling.

There are 3 Phases to this study:

- a 2-4 week Screening/Baseline Phase during which eligibility to be included in the
trial will be tested;

- a 9 week Treatment Phase during which subjects will receive CPP-109 or placebo tablets
in addition to counseling; and

- a 15 week Follow-up Phase, during the first 4 weeks (Weeks 10-13) of which subjects
will continue to receive counseling.

Inclusion Criteria:

- Able to understand the study and provide written informed consent.

- Male or female at least 18 years of age.

- Meet DSM-IV criteria for cocaine dependence as primary diagnosis, as determined by
the Substance Abuse Structured Clinical Interview (SCID) for Diagnostic and
Statistical Manual-IV (DSM-IV) module.

- Have a verifiable place of primary residence.

- Seeking treatment for cocaine dependence.

- Be in generally good health based on history, physical examination,
electrocardiogram, eye exam and laboratory findings.

- If female of childbearing potential, use acceptable contraceptive methods (oral
contraceptives (the pill), intrauterine device (IUD), contraceptive implants under
the skin, contraceptive rings or patches or injections, diaphragms with spermicide,
and condoms with spermicide). Surgical sterilization by tubal ligation or
hysterectomy is acceptable.

Exclusion Criteria:

- Please contact site for more information