Abstract – Methadone, an opioid agonist therapy, is the most effective treatment for severe opioid use disorder (OUD), and opioid treatment programs (OTPs) are the only medical settings allowed to administer this treatment. People using fentanyl in particular require methadone, as these patients are more difficult to stabilize on opioid agonist therapy. The COVID-19 pandemic exacerbated the overdose epidemic in the United States with deaths increasing 31% from 21.6 (per 100,000) in 2019 to 28.3 in 2020,2 with substantially larger increases in deaths among individuals identified as Black and American Indian. Illicitly manufactured fentanyl contributed to 64% of the more than 100,000 drug overdoses between May 2020 and April 2021. The 1972 Federal requirements for daily observed dosing of methadone in OTPs were relaxed during the COVID-19 pandemic without increased opioid overdoses and diversion. Thus, a March 2022 review of methadone regulations encouraged regulatory revision to promote patient-centered care and facilitate access to take-home methadone. To safely and effectively implement take-homes, however, OTPs need evidence that methadone is used as directed and not diverted. To provide this evidence and facilitate methadone take-homes, Sonara Health designed Sonara (from the Spanish word Soñará, “will dream”), a HIPAA-compliant web-application (app) that features integrated video dosing recording of patients drinking the take-home dose, and a tamper-evident seal that inhibits diversion attempts. Sonara also integrates an innovative measurement-based care (MBC) framework called the Opioid Craving Visual Analogue Scale (OC-VAS). The OC-VAS monitors patient outcomes in a personalized way and delivers this data to the care team, supporting more informed clinical decisions. In Phase I of this SBIR, Sonara Health tested and improved the Sonara app and integrated the MBC tool into the app. Patients and clinicians rated the Sonara Platform as usable, acceptable, and feasible for implementation in OTPs. Phase II’s three aims compare Sonara against usual take-homes in order to: 1) assess Sonara’s impact on retention in care and opioid use, 2) evaluate the MBC tool (OC-VAS) integrated into Sonara, and 3) test Sonara’s influence on patient, program and payer costs of care and patient health-related quality of life. The proposed aims position the Sonara Platform to become a standard of care across OTPs that documents appropriate use of take-home medication and informs better clinical decision-making. Wide adoption of the Sonora Platform can expand access to OTP services for people seeking methadone treatment for severe OUD. The Sonara Platform, moreover, supports the implementation of MBC for monitoring drug use disorders through automated data collection via the app and pragmatic value (a measure of risk for return to use). Increased patient-centered care (i.e., access to take-homes) improves retention in care, reduces medical transportation costs, and e...