HIV Drug Resistance: Genotype-Phenotype-Outcome Correlations (R21) | PA 17 292

Opportunity Information: Apply for PA 17 292

The National Institutes of Health (NIH) grant opportunity titled "HIV Drug Resistance: Genotype-Phenotype-Outcome Correlations (R21)" (Funding Opportunity Number PA-17-292) supports exploratory, early-stage research aimed at clarifying how HIV drug resistance affects real-world treatment success. The central focus is on connecting three layers of evidence: what the virus looks like genetically (genotype), how those genetic changes behave in functional testing (phenotype), and what actually happens to patients on therapy (clinical outcomes such as suppression, rebound, or failure). In practical terms, the opportunity is trying to fund studies that move beyond resistance mutations listed on paper and instead show how those mutations translate into measurable drug susceptibility and, most importantly, whether they predict who does well or poorly on recommended HIV regimens.

A major theme is improving genotype-phenotype correlations across diverse HIV subtypes. Much of the classic resistance knowledge base was built around subtype B, which is common in the United States and Western Europe, but globally many people live with non-B subtypes. The announcement encourages studies that test whether the same mutations carry the same meaning across different genetic backgrounds, whether subtype-specific patterns change drug susceptibility, and whether resistance interpretation needs to be refined for diverse viral lineages. This can include evaluating how combinations of mutations interact, how they shift susceptibility to specific antiretroviral agents, and whether current interpretation algorithms reliably capture these effects in non-B viruses.

Another emphasized area is the role of minority variants, meaning resistant viral populations that are present at low levels and may be missed by standard sequencing methods but can still influence treatment outcomes. The opportunity invites applications that examine whether these low-frequency variants are associated with higher risk of virologic failure, delayed suppression, or rebound, particularly when patients start or switch to recommended regimens. This line of work often involves more sensitive detection approaches and careful outcome linkage, with the goal of determining when minority resistance is clinically meaningful versus when it does not materially change prognosis.

The funding opportunity also explicitly targets the problem of discordance between genotype and treatment success or failure. In the clinic, it is common to see cases where a genotype suggests susceptibility but the patient fails therapy, or where resistance mutations are detected but the patient still achieves and maintains suppression. The NIH is seeking studies that unpack why these mismatches happen. Potential explanations include adherence patterns, drug levels and pharmacokinetics, archived resistance, viral fitness costs, compensatory mutations, sanctuary sites, assay limitations, host factors, and regimen potency or barrier to resistance. Projects that can systematically evaluate these possibilities, rather than treating them as noise, align closely with the purpose of the announcement.

The mechanism is an R21, which is typically used for exploratory, proof-of-concept, or high-impact preliminary work rather than large definitive clinical trials. The listed award ceiling is $200,000, indicating the intent to fund focused studies that can generate key data, validate novel approaches, or establish strong rationale for larger follow-on investigations. The opportunity is categorized as a discretionary grant in the health area and is tied to CFDA numbers 93.855 and 93.856, which correspond to NIH HIV/AIDS and related research funding streams. The original closing date provided is May 7, 2018, and the funding opportunity was created on May 17, 2017.

Laboratory evaluations linked to clinical correlates are particularly encouraged. That means NIH is interested in proposals that pair lab-based resistance testing (genotypic analysis, phenotypic susceptibility assays, or other functional assays) with well-characterized patient data such as regimen details, viral load trajectories, treatment history, and outcomes on recommended therapies. The goal is to make results directly interpretable for patient care and guideline-relevant decision-making, rather than producing purely in vitro findings with uncertain clinical implications.

Eligibility is broad and includes many types of U.S. and non-U.S. organizations. Eligible applicants include state, county, and local governments; special district governments; independent school districts; public and state-controlled higher education institutions; private higher education institutions; federally recognized Native American tribal governments; other Native American tribal organizations; public housing authorities/Indian housing authorities; nonprofits with or without 501(c)(3) status (excluding institutions of higher education in those nonprofit categories); for-profit organizations (other than small businesses); small businesses; and additional entities listed as "others." The announcement also highlights inclusion of Alaska Native and Native Hawaiian Serving Institutions, Asian American Native American Pacific Islander Serving Institutions (AANAPISIs), Hispanic-serving Institutions, Historically Black Colleges and Universities (HBCUs), Tribally Controlled Colleges and Universities (TCCUs), tribal governments that are not federally recognized, U.S. territories or possessions, faith-based or community-based organizations, eligible federal agencies, regional organizations, and non-domestic (foreign) entities. This breadth signals an interest in diverse settings and populations, which fits the scientific emphasis on subtype diversity and real-world outcomes across different epidemics.

Overall, this opportunity is designed to strengthen the evidence base connecting HIV resistance mutations to functional drug susceptibility and to patient outcomes, with special attention to understudied viral subtypes, low-frequency resistant variants, and the real clinical reasons that resistance test results do not always predict success or failure.

• The National Institutes of Health in the health sector is offering a public funding opportunity titled "HIV Drug Resistance: Genotype-Phenotype-Outcome Correlations (R21)" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 93.855, 93.856.
• This funding opportunity was created on 2017-05-17.
• Applicants must submit their applications by 2018-05-07. (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.

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