Study protocol for ADHERE (Applying Directly observed therapy to HydroxyurEa to Realize Effectiveness): Using small business partnerships to deliver a scalable and novel hydroxyurea adherence solution to youth with sickle cell disease.

Sickle cell disease (SCD) is an inherited blood disorder that affects approximately 100,000 Americans, primarily from underrepresented racial minority populations, and results in costly, multi-organ complications. Hydroxyurea, the primary disease-modifying therapy for SCD, is effective at reducing most complications; however, adherence to hydroxyurea remains suboptimal and is the primary barrier to clinical effectiveness. Video directly observed therapy (VDOT) has shown promise as an adherence-promoting intervention for hydroxyurea, yet previous VDOT trials were limited by high attrition from gaps in technology access, use of unvalidated adherence measures, and healthcare system limitations of delivering VDOT to patients. As such, we fostered a small business partnership to compare VDOT for hydroxyurea to attention control to address previous shortcomings, promote equitable trial participation, and maximize scalability. VDOT will be administered by Scene Health (formerly emocha Health) and adherence monitoring will be performed using a novel electronic adherence monitor developed to meet the unique needs of the target population. Adolescent and young adult patients as well as caregivers of younger patients (<11 years of age) will be recruited. In addition to visit incentives, all participants will be offered a smartphone with a data plan to ensure all participants have equal opportunity to complete study activities. The primary objectives of this pilot, multi-center, randomized controlled trial (RCT) are to assess retention and sustained engagement and to explore needs and preferences for longer-term adherence monitoring and interventions. This RCT is registered with the National Institutes of Health (NCT06264700). Findings will inform a future efficacy RCT applying VDOT to hydroxyurea to address adherence gaps and improve outcomes within this vulnerable population.