NIH HEAL PAR-25-154: Early-Stage Discovery of New Pain Targets in the Understudied Druggable Proteome (R03)

NIH HEAL PAR-25-154: Early-Stage Discovery of New Pain Targets in the Understudied Druggable Proteome (R03)

Historical status

This is a historical reference, not an open application listing. The official National Institutes of Health (NIH) Guide page for PAR-25-154 now labels the notice EXPIRED and says that applicants should check the NIH Guide for active opportunities. The notice does not announce a new cycle or successor deadline on its page. Do not treat this entry as an invitation to submit an application now; use the official NIH Guide to look for any future reissue or related HEAL announcement.

The notice was the NIH HEAL Initiative’s small-grant opportunity for early-stage work on understudied proteins that might become new pain targets. It was a formal Notice of Funding Opportunity (NOFO), not a continuously open program. The historical deadline field on this page retains 2026-07-16, the final date listed by the notice for renewal, resubmission, or revision applications. The notice listed 2026-06-16 as the final new-application date and 2026-07-17 as its expiration date. Both submission dates are past, so a new applicant should not rely on this PAR number without first finding an active NIH announcement.

At a glance

What the NOFO was designed to support

PAR-25-154 addressed a narrow discovery problem: many proteins in the druggable proteome had limited biological characterization, even though they might eventually provide useful markers or therapeutic targets. NIH sought small, self-contained projects that could produce evidence about the function of eligible proteins in pain biology. The award was intended to help a team establish a credible starting dataset or research tool for a later grant application or drug-discovery project.

The R03 mechanism shaped the expected scale. The official notice describes pilot and feasibility studies, discrete research projects, research-method development, assay development for compound-screening work, and development of human-cell or animal-based models. These are projects that can realistically be completed within one year with limited funding. A proposal that requires a long clinical program, a large multi-site infrastructure build, or a full drug-development campaign would not fit the mechanism.

The NOFO was part of the NIH HEAL Initiative, which supports research intended to improve pain management and address the opioid public-health crisis. Its scientific emphasis was earlier than clinical testing: applicants were expected to improve knowledge of an understudied protein, connect that protein to pain-related biology, and create preliminary evidence or resources that could support later work. The notice explicitly says that the awards are non-renewable, so the award itself was not a recurring operating grant.

Protein scope and responsiveness

The most important scientific eligibility rule was the protein list in the NOFO. PAR-25-154 grouped eligible targets into ion channels, transcription factors, transporters, proteases, and G-protein-coupled receptors. Examples appearing in the official list include CALHM4, KCNMB2, OTOP3, TMEM63A, and LRRC8D among ion channels; DANCR, TAF9, ZNF280C, and FOXR1 among transcription factors; SLC35E4, SLC6A16, SLC25A47, and CNNM1 among transporters; CASP12, PRSS41, WFDC9, and ADAM30 among proteases; and GPR62, MRGPRX3, GPR156, and GPR160 among GPCRs. The list is illustrative rather than exhaustive; an applicant had to check the exact official list before preparing the application.

NIH states that only applications focused on proteins in that list and meeting the responsiveness criteria would be considered responsive. Applications centered mainly on proteins outside the listed targets could be returned without review. A proposal therefore needed more than a general claim that its protein was interesting or druggable. It needed a reasoned connection between the selected protein, pain or pain management, and the proposed biochemical, cellular, animal, biomimetic, or ex vivo human-sample work.

The notice gave several examples of responsive research directions: isolating and characterizing an understudied protein; placing it in a signaling pathway; identifying or validating a pain biomarker; carrying out a preclinical animal study directed toward therapeutic development; mapping cell- or tissue-specific expression and function; testing a tool in an animal, biomimetic, or ex vivo human system; or establishing an early structure-activity relationship between protein function and a ligand. These examples all point toward a focused evidence-building project rather than clinical drug development.

Applicant eligibility

The eligible-organization list was broad within the United States. It included public and private higher-education institutions; nonprofit organizations with or without 501(c)(3) status; small businesses and other for-profit organizations; state, county, city, township, special-district, and eligible tribal governments; eligible federal agencies; U.S. territories or possessions; independent school districts; public or Indian housing authorities; Native American tribal organizations; faith-based or community-based organizations; and regional organizations.

Foreign organizations could not apply directly, and non-domestic components of U.S. organizations were also excluded. The notice allowed foreign components of U.S. organizations when they met the applicable NIH policy definition. That distinction matters for an international collaboration: a U.S. applicant could not turn an otherwise ineligible foreign organization into the applicant of record, but an allowed foreign component could participate under NIH rules.

The permitted application types were new applications and resubmissions to PAR-24-197 and PAR-25-154. The notice did not list a general renewal path as an available application type. Clinical trials were explicitly not allowed. Projects had to stay in the pain or pain-management context and could not make clinical drug development the central activity. The NOFO also required applicants to follow all applicable NIH application-guide and program-specific instructions.

Historical application route and preparation steps

Although the cycle is closed, its submission process is useful context for interpreting archived applications. NIH required electronic submission through one of the listed routes: NIH ASSIST, an institutional system-to-system solution, or Grants.gov Workspace. The applicant then used eRA Commons to track the submission. Paper applications were not the route described by this notice.

The first preparation step was to read the Research instructions in the NIH How to Apply Application Guide together with the PAR-25-154-specific instructions. NIH said that conformance to both sets of requirements was strictly enforced. A compliant team would have checked the application type, forms, page limits, attachments, budget, and any program-specific requirements before submission rather than assuming that the R03 mechanism relaxed the standard rules.

The applicant organization also needed to complete and maintain the required registrations before submitting. The notice specifically called out an active System for Award Management registration and the related organizational registration requirements. NIH warned that registration can take six weeks or more and that registration delays are not a valid reason for a late application. Investigators and institutional officials therefore needed to confirm their eRA Commons and Grants.gov arrangements well before the due date.

The historical deadline was a hard time-of-day deadline: applications were due by 5:00 PM local time of the applicant organization. New applications and renewal, resubmission, or revision applications had different dates in the table. NIH encouraged early submission so that errors discovered during the electronic submission process could be corrected before the applicable due date. For an archived application, the relevant final dates were June 16, 2026 for new applications and July 16, 2026 for the other listed application category.

Budget and project design

The application budget was limited to $100,000 in direct costs, excluding subcontract facilities and administrative costs, for a maximum one-year project period. NIH also said that budgets had to reflect the actual needs of the proposed project. The limit favored a small number of well-justified aims, clear milestones, and methods that could produce interpretable preliminary evidence within the award period.

The budget should have been tied directly to the target and the evidence gap. Depending on the project, legitimate needs could include assay reagents, protein production or purification, cell and tissue work, model-system costs, analytical services, or development of a research tool. The proposal still needed to explain why each cost was necessary and how the requested work would establish a pain-relevant result. A broad shopping list would have been weaker than a compact plan connecting each expense to a defined aim.

Coordination and data responsibilities

The notice expected HEAL award recipients to cooperate and share information after awards were made. It called for participation in Program Director/Principal Investigator meetings, including an annual HEAL Investigators Meeting, along with other coordination activities. A historical applicant should therefore have shown that the team could contribute to a coordinated research community, not only complete its own experiments.

The application also had to follow the NIH Data Management and Sharing Policy and the HEAL-specific expectations identified in the notice and related guidance. Data, tools, and associated metadata should have been planned as part of the project rather than left as an afterthought. The exact repository and reporting requirements depended on the proposed work and the applicable NIH instructions, so an archived checklist should be checked against the current NIH policy if a related opportunity is reissued.

What to do now

Do not submit under PAR-25-154. The official page marks it expired, and its last listed application dates have passed. There is no new cycle announced on that notice page. Researchers who still have a strong project concept should search the active NIH Guide for a current HEAL, pain-target, R03, or related funding opportunity and then confirm that the current announcement has the right mechanism, protein scope, application type, budget, and deadline.

The old notice remains useful for planning because it records the scientific rationale and the target families NIH considered eligible for this particular round. It can help a team organize a one-year pilot, identify the kind of preliminary evidence that would be useful, and understand why a target-focused proposal was preferred. It cannot establish that the same protein list, eligibility rules, budget ceiling, or submission dates will carry into a future announcement. Those details must be rechecked against the new official notice before any application is prepared.

Official source

The primary source is the NIH Guide page for PAR-25-154. It is retained as the official historical source even though automated HTTP access returned 403 during the metadata check; the page itself was verified and currently identifies the notice as expired.