PROJECT SUMMARY Asthma affects 9% of adolescents in the United States and is a leading cause of youth morbidity. National asthma guidelines emphasize the importance of asthma self-management behaviors to control asthma and promote quality of life. Adolescents have suboptimal adherence to asthma self-management behaviors driven by an underdeveloped and highly variable capacity to self-regulate cognitions, emotions, and behaviors; and a normative decrease in parental support while multiple demands are increasing. Each adolescent experiences different threats to their ability to self-regulate at different moments in time, necessitating personalized and adaptive self-regulatory support to increase daily self-management behaviors and achieve sustained asthma control. Smartphones are an optimal mechanism for improving adolescent adherence, however, existing asthma self-management apps do not combine what is known about evidence-based behavior change strategies and adaptive intervention technologies that tailor the experience based on user data. Our team recently developed Responsive Asthma Care for Teens (ReACT; R56 HL141394), a technological ecosystem including a smartphone app, mobile sensors to assess medication dosing, a Smarthub to achieve real-time data listening, and cloud-based intervention delivery algorithms. ReACT provides personalized and adaptive self-regulatory support to improve asthma self-management via goal-setting, feedback, and barrier identification with problem-solving skills. Results of our pilot work demonstrated that ReACT was acceptable and produced post-intervention changes in our hypothesized mechanisms of self-regulation and problem- solving skills. The proposed study will optimize ReACT based on lessons learned from our pilot work and updated national asthma guidelines. We will conduct an unbalanced (2:1) randomized pilot trial to examine feasibility of our multisite trial protocol, determine if ReACT produces a clinically significant effect on proximal mechanisms hypothesized to drive asthma control, and explore the impact of ReACT on asthma control and asthma-related quality of life. Adolescents ages 13-17 with suboptimal asthma control (n=120) will be randomized to ReACT or a mHealth control condition stratified by regimen for 6-months. Adolescents in the control condition will receive an app that includes static asthma education information and a form for recording symptoms and adherence. The control condition is designed to mirror standard of care, optimize recruitment, and sustain interest while concurrently having a minimal impact on asthma management. Assessments will occur at baseline, 3-month, and post-intervention (6-month) time points. Mechanisms of intervention effect will be collected via both self-report (e.g., self-regulation) and objective (e.g., medication adherence) assessments. We will assess planned future clinical trial outcomes (e.g., asthma control and asthma-related quality of life) to provide effe...