Exploratory/Developmental Research on Guillain Barre Syndrome (GBS) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) (R21 - Clinical Trial Not Allowed) | RFA NS 25 025

Opportunity Information: Apply for RFA NS 25 025

The National Institutes of Health (NIH) is offering an R21 exploratory/developmental research grant opportunity titled "Exploratory/Developmental Research on Guillain Barre Syndrome (GBS) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) (R21 - Clinical Trial Not Allowed)." Listed under Funding Opportunity Number RFA-NS-25-025 and CFDA 93.853, this discretionary health research grant is designed to speed up early-stage, high-impact studies that can move the field toward a clearer understanding of disease biology and, ultimately, better ways to diagnose, monitor, and treat both GBS and CIDP. The opportunity specifically emphasizes exploratory work, meaning applicants are generally expected to propose innovative ideas, proof-of-concept studies, or development of new approaches rather than large, definitive clinical efficacy trials.

The central goal of the initiative is to accelerate research that explains how immune-mediated processes lead to nerve damage and dysfunction in GBS and CIDP, and how those processes might be intercepted, measured, or reversed. Responsive projects can focus on immunological mechanisms, such as the immune pathways and cellular players that drive inflammation, demyelination, axonal injury, and impaired nerve signaling. Proposals can also address contributing genetic and epigenetic factors that may influence disease susceptibility, severity, recovery trajectories, relapse risk, or treatment responsiveness. In addition, the announcement encourages development of novel animal models and cellular model systems that better capture key features of GBS or CIDP, since improved models can enable faster testing of hypotheses about disease triggers and immune-nerve interactions.

A major area of interest is biomarker discovery and development. This includes identifying diagnostic biomarkers that could improve accuracy or speed of diagnosis, as well as biomarkers that can predict prognosis, stratify patients, or track disease activity over time. The opportunity also highlights treatment-response biomarkers, which could help clinicians determine whether a therapy is working earlier than current clinical assessments allow. Beyond biomarkers, the initiative supports research into novel treatments as well as studies that clarify the mechanisms of action of existing treatments. This could include work that explains why certain therapies help some patients but not others, what immune pathways are actually being modulated, or how treatment timing and biological context affect outcomes. Because the FOA states "Clinical Trial Not Allowed," applicants should design studies that do not meet NIH’s definition of a clinical trial; however, mechanistic human studies, analyses of biospecimens, and observational or translational work may still be relevant as long as they are structured appropriately and remain outside the clinical trial definition.

Eligibility is broad and includes many types of domestic institutions and organizations, reflecting NIH’s intent to draw ideas from across the research ecosystem. Eligible applicants include state, county, city/township, and special district governments; independent school districts; public and state-controlled institutions of higher education; private institutions of higher education; federally recognized Native American tribal governments; and Native American tribal organizations that are not federally recognized tribal governments. Nonprofit organizations are eligible whether or not they have 501(c)(3) status (as long as they are not institutions of higher education in the category specified), and for-profit organizations are also eligible (other than small businesses), as are small businesses under the general eligibility umbrella listed. Public housing authorities and Indian housing authorities are included as eligible entities as well. The announcement further calls out additional eligible applicant categories such as 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), faith-based or community-based organizations, eligible federal agencies, U.S. territories or possessions, regional organizations, and non-U.S. (foreign) organizations, indicating that NIH is open to participation from a wide range of communities and institutional settings, including international contributors when permitted.

Key administrative details included in the source data are that the opportunity is a grant (Funding Instrument Type: Grant) in the health category, created on 2024-11-13, with an original application closing date of 2025-10-03. The listing shows an award ceiling of $3,000,000, which represents the maximum amount shown in the opportunity record; applicants should still verify the allowed budget structure and project period expectations for an R21 mechanism in the full FOA, since R21 budgets are often constrained by mechanism-specific guidelines and institute policies. The record does not specify the expected number of awards, which suggests that the number of funded projects may depend on the quantity and quality of applications received and the funds NIH ultimately allocates to this initiative.

Overall, this funding opportunity is aimed at jump-starting creative, early-stage research that can open new paths in GBS and CIDP science. The strongest applications are likely to be those that clearly identify a major gap in understanding or clinical need, propose a rigorous and feasible approach to generate decisive preliminary data, and show how the work could translate into improved diagnostic tools, better disease monitoring, clearer patient stratification, or more effective therapeutic strategies, all while staying within the "no clinical trial" boundary set by the FOA.

• The National Institutes of Health in the health sector is offering a public funding opportunity titled "Exploratory/Developmental Research on Guillain Barre Syndrome (GBS) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) (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): 93.853.
• This funding opportunity was created on 2024-11-13.
• Applicants must submit their applications by 2025-10-03. (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 $3,000,000.00 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 RFA NS 25 025

[Watch] Creating a grant proposal using the step-by-step wizard inside the applicant portal: