The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) has released the *Ancillary Studies to Ongoing Clinical Projects (R21 Clinical Trial Not Allowed)* funding opportunity (PAR-25-230). This program supports time-sensitive ancillary studies conducted in conjunction with ongoing clinical projects, including clinical trials, observational studies, or disease-specific repositories actively collecting patient samples or clinical data. These studies aim to leverage existing patient cohorts, data, and infrastructure to address novel research questions related to the NIAMS mission. The ancillary studies must not duplicate the parent project but instead enhance its scientific value, addressing innovative and groundbreaking areas of research.

The primary goal of this NOFO is to support high-risk, high-reward exploratory projects with the potential for significant scientific impact. Suitable proposals may involve novel methodologies, tools, or applications of existing methods in new ways. Examples include identifying novel cellular or molecular mechanisms, biomarkers, intervention effects, or pathways underlying disease onset, progression, or comorbidities. Mechanistic and non-mechanistic studies are encouraged, as long as they align with the NIAMS mission and provide justification for expedited review and award.

Eligible applicants include higher education institutions (public, private, minority-serving), nonprofits, for-profit entities, local and tribal governments, and other organizations. Foreign components of U.S. institutions are eligible, but non-U.S. entities cannot apply. Applicants must register with SAM.gov, eRA Commons, and Grants.gov before submitting their application.

The funding provides up to $400,000 in direct costs over two years, with a maximum of $250,000 in direct costs in any single year. The application process involves submitting required forms, including a research strategy, timeline, justification for time-sensitivity, and a letter of support from the parent project leadership affirming the feasibility and availability of resources. Applications must demonstrate how the ancillary study will enhance the scientific value of the parent project without interfering with its core objectives.

The review process will focus on significance, innovation, rigor, feasibility, and investigator expertise, with an emphasis on groundbreaking research. Applications will undergo accelerated peer review to align with the timeline of the parent project. Non-responsive applications, such as those relying on already collected data or samples, will be returned without review.

Key deadlines include April 9, 2025, August 6, 2025, and December 5, 2025, with an earliest project start date approximately six months after submission. Prospective applicants are strongly encouraged to contact a NIAMS Program Director prior to submission to ensure the project is appropriate for the R21 mechanism.

For further details, including submission guidance, eligibility, and application requirements, contact Dr. Heiyoung Park (parkh1@mail.nih.gov) or refer to the official NOFO page on Grants.gov.