PROJECT SUMMARY The overarching goal of the HIV Prevention Trials Network (HPTN) is to identify acceptable, feasible, safe, effective and scalable interventions for HIV prevention that address the needs of populations at risk in the U.S. and around the world. The HPTN will address this goal by identifying: 1) new biomedical products and tools for HIV prevention that have unique characteristics, such as longer duration of action, new targets for inhibition of HIV replication, or as multipurpose prevention technologies (MPTs); and (2) integrated strategies that optimize use of proven efficacious prevention interventions and new tools tailored to specific populations at risk to achieve maximal public health impact. These interventions will be evaluated in priority populations for HIV prevention including women in sub-Saharan Africa, young men and women at risk, men who have sex with men (MSM), transgender women (TGW) who have sex with men, female sex workers (FSW) and persons who inject drugs (PWID). The specific aims of this research will be 1) To design and conduct studies of long-acting antiretroviral (ARV) agents and delivery systems for pre-exposure prophylaxis (PrEP); 2) To design and conduct studies to evaluate MPTs that concurrently prevent HIV and pregnancy, sexually transmitted infections (STIs) or opioid dependence; 3) To design and conduct studies in collaboration with the HIV Vaccine Trials Network to evaluate broadly neutralizing antibodies (bnAbs), alone and in combination, for PrEP; 4) To design and conduct integrated strategies for HIV prevention. For the first three aims, the HPTN will use a sequential multi-phase drug development strategy for the evaluation of new candidates for prevention. Phase 1 and 2 studies will be conducted for the evaluation of appropriate dose, safety and tolerability of the agent(s). The most promising systemic agents will be advanced using the criteria for a favorable target product profile for new agents including highly effective and durable protection against HIV, minimal adverse effects and drug interactions, high levels of user acceptability, and a high barrier to viral resistance. Efficacious biomedical prevention interventions will be incorporated into integrated strategy study designs that also include socio- behavioral interventions tailored to the HIV prevention imperatives and contextual needs of the specific populations at risk for HIV infection. Socio-Behavioral research (SBR) will be integral to the success of all aspects of the proposed HPTN HIV prevention agenda. Supportive SBR will be used to strengthen biomedical HIV product development (i.e. to inform user preference and ultimately product design for Phase 1-3 clinical trials), while integrative SBR will play a key role in the process of designing and adapting behavioral and structural interventions to complement biomedical interventions in integrated strategy studies. The HPTN will design and conduct the research through collaboration with its scientific leadership, its research teams, community partners, research participants, pharmaceutical companies and funders.