This symposium will discuss the different perspectives and lessons learned from individuals across multiple disciplines. This will include discussions regarding the development of clinical outcome assessment strategies to support product registration; effective collaboration with patient advocacy groups and clinicians; and creation of economic models to support health technology assessment. Ms. Deal will speak to the challenges and opportunities when developing COA measurement strategies to support the registration of products intended to treat rare conditions. Her presentation will include discussion of the development of novel COAs in these patient populations (when required), including planning and implementing successful qualitative studies and partnering with patient advocacy organizations. Implications for the evaluation of COAs in the context of smaller clinical trial samples will also be discussed. Professor Fricke will speak to the challenges and opportunities payers face surrounding rare and orphan disease treatment decision making. What are the evidence requirements needed for positive appraisals and implications given the small and heterogeneous patient populations being assessed. Mr. Knight will speak to the challenges and opportunities that manufacturers face providing clinical and economic arguments to support treatments in rare diseases. He will explore how best to utilize the limited availability of data and the importance of support from clinician and patient advocacy groups.