DESCRIPTION: Members of the ISPOR COA Measurement in Rare Disease Clinical Trials — Emerging Good Practices Task Force have developed a report on the challenges and suggested solutions for identifying and validating clinical outcome assessments (COAs) to measure treatment benefit in rare disease clinical trials. Drawing on the COA framework specified in the US FDA Roadmap to Patient-Focused Outcome Measurement in Clinical Trials, recommendations focus on methods for COA instrument selection, adaptation, and validation.  Conformance to regulatory guidance for the evaluation and proof of treatment benefit using COA endpoints is taken into account regarding how measures and methods can be developed or adapted recognizing the unique challenges of rare diseases.    The authors will use the example of systemic amyloidosis, a rare disease affecting multiple organs that can lead to progressive disability or death, to illustrate the issues in measuring treatment benefit from the patient perspective 1) when the condition is highly heterogeneous and 2) where patients may experience a wide range of symptoms that vary across subtypes.     After outlining the task force’s recommendations, members of the audience will apply these recommendations to the systemic amyloidosis example to 1) better understand the difficulties inherent in assessing COAs in rare disease populations, and 2) to get a feel for using the solutions included in the task force report.   This forum will provide a hands-on experience on how to construct endpoints to measure outcomes of importance to patients with rare diseases, their caregivers and clinicians, within the context of a clinical trial. As such, it will be useful to researchers, clinicians, and others involved in developing or evaluating rare disease treatments.