An open-label study designed to evaluate the safety, tolerability, and pharmacokinetics of ALA-1000 in opioid-dependent subjects. To characterize the PK profile of ALA-1000 in 5 single ascending dose cohorts and a sixth cohort of single ALA-1000 after receiving buprenorphine sublingual films for 7 days.

The study will include opioid-dependent subjects who have been receiving stable, orally administered buprenorphine for at least 2 weeks or buprenorphine naïve subjects who will be stabilized on orally administered buprenorphine for 3 days prior to ALA-1000 administration.

All subjects will be washed off of oral buprenorphine for 7 days prior to ALA-1000 administration except Cohort 6 which will receive ALA-1000 administration after 7 days of buprenorphine sublingual film dosing.

The subsequent cohorts will be initiated after safety and PK information from the preceding cohorts is available.

The expected maximum duration of participation for each subject is 192 days approximately, consisting of up to a 7-day screening period, up to a 31-day residential phase, and up to a 154-day nonresidential period.

Inclusion Criteria:

1. Competent to provide informed consent.
2. Voluntarily provide informed consent and Health Insurance Portability and Accounting Act (HIPAA) Authorization prior to any procedures or evaluations performed specifically for the sole purpose of the study.
3. Male or female between 18 to 65 years of age inclusive at the screening visit.
4. Meets DSM-5 criteria for Opioid Use Disorder (OUD) and is seeking treatment of OUD.
5. Body Mass Index (BMI) ≥ 18 and ≤ 35 kg/m2 at screening visit.
6. Female subjects of childbearing potential must agree to use a reliable method of birth control (e.g., total abstinence, condom and spermicide, intrauterine device (IUD), oral contraception which has been stable for 30 days) and at least 120 days after stopping the investigational product.
7. Agree to withdraw from opiates for at least 12 hours prior to admission to clinical unit.
8. Agree not to take any buprenorphine product (other than ALA-1000 and buprenorphine sublingual films during tolerability/induction period) during the study.

Exclusion Criteria:

1. History or presence of a significant medical disease or disorder which, in the opinion of the investigator, increases the risk of the study drug or may confound the interpretation of study measures, as confirmed by screening laboratory results.
2. Clinically significant abnormal findings on physical examination, vital signs, or Electrocardiogram (ECG). Defined as having a QTc (Fridericia) interval > 470 msec or any other clinically significant abnormalities at screening, check-in, or prior to administration of ALA-1000.
3. Pregnant or lactating.
4. History of suicidal behavior in the past 1 year or current suicidal ideation as per investigator judgement.
5. Currently meets Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for substance use disorder, moderate or severe for any substance other than opioids, caffeine, or nicotine.
6. Currently meets criteria for any unstable psychiatric disorder, including schizophrenia, schizoaffective, bipolar disorder (depression and stable bipolar disorder are not excluded if condition has been stable for at least 60 days).
7. Current diagnosis of Acquired Immune Deficiency Syndrome (AIDS) as confirmed by Western Blot and viral load laboratory results.
8. Acute active Hepatitis B or C as evidenced by positive serology and Aspartate aminotransferase (AST)/ Alanine aminotransferase (ALT) >2 upper limit of normal (ULN)
9. History of blood donation in excess of 450 mL within 30 days prior to Visit 1.
10. Received treatment with an investigational drug or device within 90 days prior to Visit 1.
11. Use of strong inhibitors or inducers of cytochrome P450 3A4 (CYP3A4) within 30 days prior to Visit 1.
12. Use of any new medication, vitamins, or supplements within 7 days prior to Visit.
13. Hypersensitivity or allergy to buprenorphine or other opioids which, in the opinion of the investigator, would compromise subject safety.