Adolescents and young adults (AYA) under the age of 25 in the United States (US) are the least likely of all age groups to: 1) know their HIV status, 2) initiate PrEP if HIV-negative even when indicated, 3) take medication as prescribed, attend medical appointments, and be virally suppressed if living with HIV. Persistent rates of new infections among US youth indicate that evidence-based and integrated approaches to increase the uptake and use of effective biomedical prevention and treatment products are required. Adolescence and young adulthood are challenging developmental periods, with significant physical, neurocognitive, emotional, and social changes. While multiple vulnerabilities and complex community factors drive the HIV epidemic among youth, these developmental periods are also characterized by opportunities for growth, achievement, and resilience. HIV research networks must be broad in agenda, go beyond traditional clinical sites and individual level interventions and address the multi-faceted, multi-level barriers that have thwarted HIV prevention and care progress among AYA. The newly envisioned Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) is a multi- component collaborative research enterprise focused on the reduction of new HIV infections among AYA in the US as well as improvements across the HIV continuum of care for youth living with HIV. Such a large-scale, complex clinical research program demands high productivity and strong contributions from each essential component. Our proposed overall network structure is conceptualized as a well-oiled machine with interdependent structures working together seamlessly to achieve the mission of the ATN. The Scientific Leadership Center (SLC) will bring all elements together and ensure that they function collaboratively, effectively, and efficiently with the Operations and Collaboration Center (OCC), NIH, and the overall network. The ATN has identified five high priority research areas to address the substantial and disproportionate gaps in the health outcomes of AYA across the HIV prevention and care continuum. With this application, we include seven highly innovative and impactful clinical trials led by talented multi-disciplinary teams, addressing all five priority research areas, spanning key populations of youth, multiple socioecological systems, and a variety of regulatory phases. We are also poised to accept emerging research opportunities as the field of prevention and treatment science advances. Communities will be situated at the center of the ATN’s work because community ownership, engagement, and connectedness are critical for successful research implementation. Drs. Hightow-Weidman and Hosek are uniquely qualified as MPIs to lead the SLC. Both have worked in the field of adolescent HIV prevention and treatment for the entirety of their careers and have worked collaboratively within the ATN for >16 years, giving them clear insight on how best to make this new iteration successful. Our overall vision for a redesigned and robust ATN is one that not only anticipates and plans for ongoing evolution in the HIV field and an emerging scientific agenda but one with a renewed focus on the most impactful science and priority areas.

The newly envisioned Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) is a multi- component collaborative research enterprise focused on the reduction of new HIV infections among adolescents and young adults in the US as well as improvements across the HIV continuum of care for youth living with HIV. The Scientific Leadership Center (SLC), led by Drs. Hightow-Weidman and Hosek, will bring all elements together and ensure that they function collaboratively, effectively, and efficiently with the Operations and Collaboration Center (OCC), NIH, and the overall network. Seven highly innovative and impactful clinical trials, led by talented multi-disciplinary teams that address all five ATN priority research areas, span key populations of youth, multiple socioecological systems, and a variety of regulatory phases are included.