Pilot Studies of Biological, Behavioral and Social Mechanisms Contributing to HIV Pathogenesis Within the Mission of the NIDDK (R21 Clinical Trial Not Allowed) | PAR 21 062

Opportunity Information: Apply for PAR 21 062

The Pilot Studies of Biological, Behavioral and Social Mechanisms Contributing to HIV Pathogenesis Within the Mission of the NIDDK (R21 Clinical Trial Not Allowed) funding opportunity (PAR-21-062) is a National Institutes of Health (NIH) discretionary grant program that supports early-stage, innovative pilot projects focused on HIV/AIDS research questions that intersect directly with the mission areas of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). It is designed for basic and translational studies, meaning applicants can propose laboratory, preclinical, mechanistic, and human-subjects research aimed at understanding disease processes, as long as the work does not involve a clinical trial. The overarching expectation is that proposed projects align with NIH HIV/AIDS research priorities as outlined by the NIH Office of AIDS Research (OAR), specifically referencing the guidance in NOT-20-018 on HIV/AIDS priorities and how HIV-related funding determinations are made.

The core scientific emphasis is on uncovering mechanisms of HIV pathogenesis that drive comorbidities, coinfections, and complications (often abbreviated as CCCs) in organs, tissues, and biological systems that fall under NIDDKs portfolio, such as metabolic disease, diabetes-related pathways, digestive and liver diseases, kidney and urologic disorders, nutrition, obesity, and related endocrine and gastrointestinal processes. In practical terms, this FOA is looking for studies that explain why and how HIV infection, long-term antiretroviral therapy, chronic inflammation, immune dysregulation, or viral persistence contribute to downstream health problems in NIDDK-relevant systems. Projects can also focus on the distinctive pathophysiology of HIV in these contexts, for example by identifying molecular pathways, cellular interactions, or host responses that make HIV-associated complications different from similar conditions in people without HIV.

A second major theme is HIV reservoirs, particularly the biological mechanisms that allow HIV to persist in tissues that matter to NIDDKs mission. Reservoir research here is framed as mechanistic work that can inform strategies for durable viral suppression or eventual eradication. That can include investigating which cell types harbor persistent virus, what tissue microenvironments support persistence, how metabolic or inflammatory states influence reservoir dynamics, and which host pathways might be targeted to disrupt persistence in NIDDK-relevant compartments. The intent is not simply to measure reservoirs, but to generate mechanistic insight that can become the foundation for more definitive studies and future interventions.

A third theme explicitly broadens the scope beyond biology to include behavioral and social mechanisms, especially social determinants of health that impede health outcomes and may worsen HIV-related comorbidities or influence viral reservoirs through multiple pathways. This makes room for research that connects structural or social exposures (such as poverty, housing instability, food insecurity, access to care, stigma, or other contextual factors) to biological or clinical consequences in NIDDK-relevant disease processes. The strongest fit is likely projects that can plausibly link these determinants to mechanistic outcomes, pathways, or measurable disease processes rather than purely descriptive work.

Administratively, this is an R21 mechanism, which typically supports exploratory, high-impact pilot work meant to generate proof-of-concept data rather than fully mature, large-scale programs. The listed award ceiling is $200,000, signaling a small, focused budget appropriate for preliminary mechanistic studies, method development, or tightly scoped translational projects. The activity category is listed under health (and also tagged with food and nutrition), reflecting NIDDKs broad remit and the FOAs interest in HIV-related complications affecting metabolic and digestive systems as well as kidney disease and related processes. The opportunity is marked as clinical trial not allowed, so applicants need to ensure the proposed human work, if any, does not meet NIHs definition of a clinical trial (for example, assigning human participants to interventions to evaluate effects on health-related outcomes).

Eligibility is broad and includes a wide mix of domestic and non-domestic organizations. Eligible applicants include state, county, city or township governments, special district governments, independent school districts, public and state-controlled institutions of higher education, private institutions of higher education, and a range of nonprofit organizations (with or without 501(c)(3) status) as well as for-profit organizations (other than small businesses) and small businesses. The FOA also highlights a number of institutions and entities that are explicitly welcomed as other eligible applicants, including Historically Black Colleges and Universities (HBCUs), Hispanic-serving Institutions, Tribally Controlled Colleges and Universities (TCCUs), Alaska Native and Native Hawaiian Serving Institutions, and Asian American Native American Pacific Islander Serving Institutions (AANAPISISs), along with faith-based or community-based organizations, eligible federal agencies, tribal governments that are not federally recognized, regional organizations, foreign organizations, and U.S. territories or possessions. This breadth signals an interest in encouraging participation from diverse institutional settings and communities, which fits the FOAs inclusion of social determinants and population-linked mechanisms.

Key dates and identifiers in the source information include a creation date of January 11, 2021, and an original closing date listed as January 7, 2024. The sponsoring agency is NIH, and the assistance listing is associated with CFDA number 93.847. Overall, the program is best understood as a targeted call for exploratory HIV-related mechanistic research that directly informs NIDDK-relevant disease areas, with the flexibility to incorporate biological, behavioral, and social pathways, provided the work remains within the R21 pilot scope and avoids clinical trial designs.

• The National Institutes of Health in the food and nutrition, health sector is offering a public funding opportunity titled "Pilot Studies of Biological, Behavioral and Social Mechanisms Contributing to HIV Pathogenesis Within the Mission of the NIDDK (R21 Clinical Trial Not Allowed)" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 93.847.
• This funding opportunity was created on 2021-01-11.
• Applicants must submit their applications by 2024-01-07. (Agency may still review applications by suitable applicants for the remaining/unused allocated funding in 2026.)
• Each selected applicant is eligible to receive up to $200,000.00 in funding.
• Eligible applicants include: State governments, County governments, City or township governments, Special district governments, Independent school districts, Public and State controlled institutions of higher education, Native American tribal governments (Federally recognized), Public housing authorities/Indian housing authorities, Native American tribal organizations (other than Federally recognized tribal governments), Nonprofits having a 501 (c) (3) status with the IRS, other than institutions of higher education, Nonprofits that do not have a 501 (c) (3) status with the IRS, other than institutions of higher education, Private institutions of higher education, For-profit organizations other than small businesses, Small businesses, Others.

Apply for PAR 21 062

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