Cariprazine Impact on Cocaine Use in OUD-CocUD Patients on Buprenorphine-naloxone

This study is a phase 2 trial that aims to explore the effects of a low dose of a medication called Cariprazine (1.5mg/d) on cocaine use in patients who are medically-stable and have Opioid Use Disorder (OUD) with co-occurring Cocaine Use Disorder (CocUD). These patients are already taking a stable dose of Buprenorphine-naloxone (BUP-NX) for at least one week. The study is designed as a relapse-prevention study for patients who have a cocaine-negative urine at the time of study enrollment. The importance of this study lies in its potential to improve treatment for patients dealing with both OUD and CocUD, addressing a significant challenge in current care. Approximately 48 subjects will participate in this single-blind study, where they will be unaware of their medication status. Participants will be randomly assigned to receive either Cariprazine or a placebo in a 2:1 ratio. The study will last for about 11 weeks, including a screening period and a follow-up visit. During this time, subjects will complete various assessments, behavioral tasks, and neurocognition probes monitored by fNIRS. They will take Cariprazine (or placebo) daily for 8 weeks. Urine and blood samples will be collected regularly to monitor compliance and cocaine use. The primary outcome of the study is to measure the impact of Cariprazine (vs. placebo) on cocaine use, as indicated by the percentage of cocaine-positive or missing urine samples across weeks 3-8.