A Bioavailability and Safety Study of Probuphine Versus Sublingual Buprenorphine in Patients With Opioid Dependence

This is an open-label study intended to evaluate the relative bioavailability of 4 Probuphine
implants versus 16mg QD sublingual buprenorphine, as determined by plasma BPN AUC(0-24),
during 24 hours at steady state. This study will also provide open-label safety and
tolerability data in patients treated with Probuphine.

Inclusion Criteria:

- Voluntarily provide written informed consent prior to the conduct of any study related
procedures

- Male or female, 18-75 years of age

- Meet the DSM-IV criteria for current opioid dependence

- Females of childbearing potential and fertile males must use a reliable means of
contraception

Exclusion Criteria:

- Current diagnosis of Acquired Immune Deficiency Syndrome (AIDS)

- Received treatment for opioid dependence (e.g., methadone, BPN) within the previous 90
days

- Current diagnosis of chronic pain requiring opioids for treatment

- Candidates for only short term opioid treatment or opioid detoxification therapy

- Pregnant or lactating females

- Previous hypersensitivity or allergy to BPN or EVA-containing substances or naloxone

- Current use of agents metabolized through Cytochrome P450 3A4 (CYP 3A4) such as azole
antifungals (e.g., ketoconazole), macrolide antibiotics (e.g., erythromycin), and
protease inhibitors (e.g., ritonavir, indinavir, and saquinavir)

- Current history of coagulopathy, and/or anti-coagulant therapy (such as warfarin)

- Meet the DSM-IV criteria for current dependence on any other psychoactive substances
other than opioids or nicotine (e.g., alcohol, sedatives)

- Current use of benzodiazepines other than physician prescribed use

- Significant medical or psychiatric symptoms, cognitive impairment, or other factors
which in the opinion of the Investigators would preclude compliance with the protocol,
patient safety, adequate cooperation in the study, or obtaining informed consent

- Concurrent medical conditions (such as severe respiratory insufficiency) that may
prevent the patient from safely participating in study; and/or any pending legal
action that could prohibit participation and/or compliance in study

- Participated in a clinical study within the previous 8 weeks

- Previous participation in a Probuphine clinical trial

- Presence of aspartate aminotransferase (AST) levels greater than or equal to 3 X upper
limit of normal and/or alanine aminotransferase (ALT) levels greater than or equal to
3 X upper limit of normal and/or total bilirubin greater than or equal to 1.5 X upper
limit of normal and/or creatinine greater than or equal to 1.5 X upper limit of normal

- Clinically significant low platelet count with current history of coagulopathy