Study is to provide ongoing treatment with RBP-6000 and safety monitoring for subjects who complete the RB-US-13-0003 study (NCT02510014) and for whom a new treatment venue has not been identified or arranged.

This is a multi-center, open-label, RBP-6000 treatment extension study in which subjects who have completed the End of Study (EOS) procedures for study RB-US-13-0003 are eligible. EOS assessments completed at the RB-US-13-0003 EOS visit serve as part of the screening visit for this study. In addition, subjects were requested to complete a Columbia Suicide Severity Rating Scale (C-SSRS) baseline/screening survey and a medical history and height was obtained.

The informed consent may be shared with subjects up to 2 months prior to the RB-US-13-0003 EOS visit, however should not be signed until all assessments for the EOS visit have been completed.

On Day 1, eligible subjects receive a subcutaneous (SC) injection of RBP-6000 at a low or high dose based on the medical judgment of the investigator. After the injection, vital signs and the injection site were assessed. Prior to departing the site, subjects were also assessed for adverse events (AEs) and use of concomitant medications (ConMeds).

Subjects return to the site for monthly injection visits every 28 days (-2 / +7 days) for a total of up to 6 injections (participants were not required to complete all 6 injections). At each subsequent visit (Injections 2 through 6) the following procedures / assessments were performed : urine pregnancy test performed for all female subjects who are of childbearing potential before each injection; previous injection site assessed for potential reaction and evidence of attempts to remove the depot; vital signs collected pre and post each injection; RBP-6000 injection, urine drug screen (UDS); C-SSRS since last visit assessment, counseling (manual-guided behavioral therapy); use of ConMeds; local injection site grading, subject self-assessment of injection site pain (Injection Site Pain Visual Analog Scale [VAS]), assessment for adverse events (AEs).

Laboratory tests (hematology, chemistry and urinalysis) may be requested by the Investigator on an ad-hoc basis in order to assess for AEs.

A subject's alternative treatment options were assessed at least two months before EOS at each visit.

At EOS or early termination (ET), the following assessments were performed: urine pregnancy test performed for all female subjects who are of childbearing potential; vital signs; previous injection site assessed for potential reaction and evidence of attempts to remove the depot; UDS; C-SSRS since last visit assessment, counseling (manual-guided behavioral therapy); use of ConMeds; assessment for AEs; a brief physical exam; height and body weight were measured and a subject's body mass index (BMI) and waist-to-hip ratio calculated; laboratory tests (hematology, chemistry, urinalysis).

Subjects were to be contacted by telephone approximately 4 weeks after EOS/ET for a safety follow-up assessment of AEs and use of ConMeds.

Inclusion Criteria:

1. Provide written consent to participate in this study.

2. Completed the End of Study Visit for the RB-US-13-0003 study (NCT02510014).

3. Be considered eligible in the medical judgment of the Investigator.

4. Females: Women of childbearing potential (defined as all women who are not surgically sterile or postmenopausal for at least 1 year prior to informed consent form (ICF)) must have a negative pregnancy test prior to enrollment and must agree to use a medically acceptable means of contraception from screening through at least 6 months after the last dose of investigational medicinal product (IMP).

   Males: Subjects with female partners of child-bearing potential must agree to use medically acceptable contraception after signing the ICF through at least 6 months after the last dose of IMP. Male subjects must also agree not to donate sperm during the study and for 6 months after receiving the last dose of IMP.

5. Subjects must agree not to take any buprenorphine products other than those administered during the current study throughout participation in the study.

6. Subjects must be willing to adhere to study procedures.

Exclusion Criteria:

1. Subject compliance issues during participation in the RB-US-13-0003 study which, in the opinion of the Investigator, could potentially compromise subject safety.
2. Women of childbearing potential who have a positive pregnancy test at RB-US-13-0003 at the end-of-study (EOS) visit, who are pregnant or breastfeeding, seeking pregnancy, or failing to use adequate contraceptive methods during the study.
3. History of suicidal ideation within 28 days prior to signing the ICF as evidenced by answering "yes' to questions 4 or 5 on the suicidal ideation portion of the Columbia-Suicide Severity Rating Scale (C-SSRS) "since last visit" assessment (completed in the EOS Visit for Study RB-US-13-0003), screening/baseline" assessment for the current study), or history of a suicide attempt (per the C-SSRS) in the 6 months prior to signing the ICF.
4. Taking any cytochrome P450 3A4 and 2C8 inducers and inhibitors, self-reported additional buprenorphine, or over the counter (OTC) and/or herbal supplements with the potential to prolong QTc within 28 days of Day 1 unless prior written approval was obtained from the Medical Monitor.