Development and Application of PET and SPECT Imaging Ligands as Biomarkers for Drug Discovery and for Pathophysiological Studies of CNS Disorders (R01 Clinical Trial Optional) | PAR 23 164

Opportunity Information: Apply for PAR 23 164

The National Institutes of Health (NIH) is offering a discretionary research grant opportunity under Funding Opportunity Number PAR 23 164 titled "Development and Application of PET and SPECT Imaging Ligands as Biomarkers for Drug Discovery and for Pathophysiological Studies of CNS Disorders (R01 Clinical Trial Optional)." This program uses the R01 grant mechanism and supports health-related research aimed at creating and validating new molecular imaging tools for the human brain. The central purpose is to speed the development of new positron emission tomography (PET) and single photon emission computed tomography (SPECT) radioligands that can function as biomarkers in central nervous system (CNS) research, including both drug discovery efforts and studies that improve understanding of disease biology.

The FOA specifically invites applications that focus on the development and evaluation of novel PET or SPECT radioligands for imaging targets in the human brain. A key emphasis is on generating the practical, decision-quality evidence needed to move promising imaging ligands forward into clinical research use. In other words, the goal is not just early chemistry or proof-of-concept in isolation, but a package of results that demonstrates why a ligand is likely to be useful and feasible in human studies. The announcement also allows applicants to incorporate pilot or clinical feasibility evaluations that draw on previously collected pre-clinical data, which signals that NIH is interested in projects positioned to transition from preclinical groundwork into translational and human-brain imaging readiness.

Because the FOA is framed around biomarkers for drug discovery and pathophysiological studies, projects can be relevant to multiple CNS disorders and therapeutic areas, as long as the work is centered on imaging ligand development and evaluation. Radioligands developed under this program would ideally enable researchers to measure things like receptor or transporter availability, enzyme activity, abnormal protein aggregates, neuroinflammation-related targets, synaptic density markers, or other disease-relevant molecular processes in vivo. These types of tools can help answer drug development questions (for example, whether a drug engages its intended target in the brain, what dose achieves adequate occupancy, or whether treatment changes a biological pathway) and can also strengthen mechanistic studies of CNS disorders by providing quantitative, noninvasive readouts in living subjects.

The funding instrument is a grant within the NIH health funding activity area, with CFDA numbers 93.242 and 93.866 listed for the program. The FOA is labeled "Clinical Trial Optional," meaning applications may include a clinical trial component if appropriate, but a clinical trial is not required. This optionality is consistent with the translational nature of imaging-ligand work, where some projects may focus on ligand development and validation steps that precede formal clinical trials, while others may be ready for early human feasibility assessments.

Eligibility is broad and includes many organizational types. Eligible applicants listed 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; other Native American tribal organizations; public housing authorities/Indian housing authorities; nonprofits with or without 501(c)(3) status (excluding institutions of higher education where specified); for-profit organizations other than small businesses; small businesses; and other entities. The announcement also highlights additional eligible applicant categories such as Alaska Native and Native Hawaiian Serving Institutions, Asian American Native American Pacific Islander Serving Institutions (AANAPISI), Hispanic-serving Institutions, Historically Black Colleges and Universities (HBCUs), Tribally Controlled Colleges and Universities (TCCUs), faith-based or community-based organizations, eligible federal agencies, regional organizations, U.S. territories or possessions, and non-domestic (non-U.S.) entities (foreign organizations). This wide eligibility scope is meant to encourage participation across academic, clinical, governmental, and private-sector research settings, including institutions serving historically underrepresented communities and international collaborators where relevant.

Key administrative details provided include an original closing date of 2026-05-07 and a creation date of 2023-04-07. Award ceiling and expected number of awards are not specified in the provided source data, which typically means applicants would need to consult the full FOA text and NIH institute-specific guidance for budget expectations, project period limits, and any priorities or constraints tied to particular participating NIH components.

In practical terms, a strong application under this FOA would usually present a clear biological target with CNS relevance, a rational ligand design and radiochemistry plan, and an evaluation strategy that demonstrates imaging performance and translational promise. That evaluation often includes evidence about binding specificity and selectivity, brain penetration and kinetics, signal-to-noise characteristics, quantification approaches, and feasibility considerations that determine whether the ligand can realistically be deployed in human research settings. The overarching theme of the opportunity is to support imaging ligand work that is far enough along, and sufficiently rigorous, to meaningfully advance PET/SPECT biomarkers toward clinical research utility in CNS disorders and neurotherapeutics development.

• The National Institutes of Health in the health sector is offering a public funding opportunity titled "Development and Application of PET and SPECT Imaging Ligands as Biomarkers for Drug Discovery and for Pathophysiological Studies of CNS Disorders (R01 Clinical Trial Optional)" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 93.242, 93.866.
• This funding opportunity was created on 2023-04-07.
• Applicants must submit their applications by 2026-05-07. (Agency may still review applications by suitable applicants for the remaining/unused allocated funding in 2026.)
• 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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