OPTIMISTIC is a proposal for a European collaborative project of doctors, scientists, relevant stakeholders (TREAT-NMD, patient organizations) and SMEs with the aim to improve clinical practice for patients suffering from a rare, inherited, and neglected disease, myotonic dystrophy type 1 (DM1). It is one of the most variable human diseases with complex, multi-systemic and progressively worsening clinical manifestations. Despite the huge impact of DM1 on the daily life of both patients and their family members, DM1 patients fail to receive the quality of healthcare that is available as they are not assertive users of the health care system.There is no cure for DM1. The aim of treatment is to relieve impairments, reduce limitations and support participation in everyday activities. Based on our DM1-specific model which shows that physical activity and experienced fatigue are main determinants of DM1 health status (Kalkman 2007), OPTIMISTIC investigates the effect of cognitive behavioural therapy (CBT) in combination with exercise training to improve functional capacity and to stimulate an active lifestyle.OPTIMISTIC compares the outcome of a treatment regimen with regular management in a multi-centre, assessor-blinded, randomized controlled trial, designed to 1) result in evidence-based clinical guidelines on exercise and cognitive behavioural therapy in DM1, 2) capture clinically meaningful changes in existing and novel outcome measures, and 3) identify both individual and composite biomarkers as surrogate treatment outcome measures that are reflective of the disease state.There is an urgent need for an European clinical trial infrastructure for DM1. High prioritization of this is required to enhance the speed of clinical development of new putative DM1 therapeutics approaching the market. OPTIMISTIC will provide this and safeguard the rapid uptake of the developed clinical guidelines ensuring improvements in DM1 care and quality of life.