Electronic Cigarettes as a Harm Reduction Strategy Among People with Opioid Use Disorder on Buprenorphine - PROJECT SUMMARY/ABSTRACT Candidate and career development: I am an Assistant Professor at Clemson University, proposing a K01 career development plan and research plan to prepare me to become an independent clinical research scientist and leader in developing and implementing innovative and feasible Electronic Cigarette (EC) protocols across clinical settings to reduce the combustible cigarette (CC) burden among people with opioid use disorder (OUD) on buprenorphine. This proposal builds on my expertise in nicotine and opioid research and extends it in important ways. The goal of the career development plan focuses on six skill areas: (1) qualitative methods, (2) quantitative methods, (3) ecological momentary assessment (EMA), (4) tobacco regulatory science, (5) grant writing, and (6) leadership skills. Mentorship team: The proposed mentorship team is truly multidisciplinary, with backgrounds in addiction medicine, public health, psychology, and biostatistics. Each mentor will contribute distinctive expertise to facilitate my progression as an independent clinical researcher. All proposed mentors have previous experience mentoring successful mentees or K awardees, with exceptional records of scientific publications and extramural grant funding. Research strategy: Evidence supports the use of EC in reducing the number of cigarettes smoked per day (CPD) or switching away from CC among adults in the general population. However, people with OUD are underrepresented in such studies. EC flavor and use frequency may influence switching and reducing CPD in people without OUD. Adult CC smokers prefer sweet flavors to tobacco flavors, and cooling flavors may further enhance the sensory experience of sweet flavors. Use of flavored EC, other than tobacco, has been linked to an increased likelihood of reducing CPD or switching to EC among CC smokers without OUD. To our knowledge, no study has systematically tested the impact of EC flavor and patterns of EC use on harm reduction milestones (e.g., CPD reduction, switching) among people with OUD. In a three-group randomized controlled trial (RCT), exclusive CC users (N=90) with OUD on buprenorphine, who are not interested in quitting, will be recruited across rural and urban outpatient settings. These participants will receive counseling and be randomly assigned to receive a 12-week supply of sweet-cooling, sweet non-cooling, or tobacco-flavored EC. Ecological momentary assessment (EMA) methodology will enable us to examine patterns of EC use associated with important harm reduction milestones. This K01 aims to offer expertise in advanced quantitative statistics, EMA, qualitative research, grant writing, and leadership development, alongside a mentored research experience to achieve the following specific aims: (1)Testing the effect of EC flavors on CPD reduction, switching, and other harm reduction milestones; (2) Characterizing rates and patterns associated with harm reduction milestones; (3) Identifying barriers and facilitators in implementing and maintaining the EC protocol.