The Clinical Trial Readiness for Rare Diseases, Disorders, and Syndromes (R03 Clinical Trial Not Allowed) research funding program from the National Institutes of Health supports clinical projects that address critical needs for clinical trial readiness in rare diseases. The initiative seeks applications that are intended to facilitate rare diseases research by enabling efficient and effective movement of candidate therapeutics or diagnostics towards clinical trials, and to increase their likelihood of success through development and testing of rigorous biomarkers and clinical outcome assessment measures, or by defining the presentation and course of a rare disease to enable the design of upcoming clinical trials. The R03 small grant supports discrete, well-defined projects that realistically can be completed in two years and that require limited levels of funding. Applicants may apply for up to 50,000 USD/year for up to 2 years. Opportunity ID: PAR-23-160. The next letters of intent are due on September 17, 2023 and full applications are due on October 17, 2023.