A long-term cost-effectiveness model for early decision-making and estimation of outcomes of novel therapeutic procedures for Parkinson's disease (PD) was developed based on the Hoehn and Yahr (HY) stages of PD. Results provided support for model validity. Model application to a future dopamine cell replacement therapy indicated long-term cost offsets and gains in quality-adjusted life years (QALYs) in early onset PD (HY III-IV), as compared to standard drug therapy. The maximum price premium (i.e., profit or compensation for developmental costs) for the intervention to remain cost-effective was estimated to euro12000-64000 according to cost-per-QALY thresholds of euro38000-70000 and depending on whether all or only medical direct costs are considered. The study illustrates the value of early health economic modeling and the described model shows promise as a means to estimate outcomes and aid decision-making regarding novel interventions for PD.