The National Institutes of Health (NIH) is offering a grant opportunity titled "Preclinical Proof of Concept Studies for Rare Diseases (R21 Clinical Trial Not Allowed)". This grant aims to provide funding for conducting efficacy studies in an established rare disease preclinical model. The goal is to demonstrate that a proposed therapeutic agent warrants further development. The supported studies will include preclinical efficacy, as well as accompanying pharmacodynamic and pharmacokinetic studies. The therapeutic agents can include small molecules, biologics, or biotechnology-derived products. The ultimate objective of this grant is to advance projects to a stage where they would attract subsequent investment for full Investigational New Drug (IND) application development or progression to clinical trials, particularly for repurposing or repositioning purposes. The grant has a maximum award ceiling of $275,000 and does not require cost sharing or matching. The eligibility criteria include various types of institutions and organizations, such as Alaska Native and Native Hawaiian Serving Institutions, Faith-based or Community-based Organizations, and U.S. Territories or Possessions. Non-domestic (non-U.S.) entities and components are not eligible to apply. The deadline for application submission is June 2, 2026. For more information and to apply, please visit the following link: Preclinical Proof of Concept Studies for Rare Diseases Grant. For any inquiries, please contact NIH Grants Information at grantsinfo@nih.gov.