Continuous subcutaneous apomorphine infusion is used in advanced Parkinson disease when oral levodopa provides inadequate control of motor fluctuations. The 2025 US InfusON phase 3 open-label study followed patients who continued to experience at least three hours of daily OFF time despite optimized levodopa and other adjunctive treatment. Participants received individualized continuous apomorphine infusion with dose titration for efficacy and tolerability and were then followed through maintenance treatment. The study provides contemporary real-world evidence that continuous infusion can reduce OFF time and improve motor fluctuations over longer follow-up. Because the study was open-label and had attrition over time, it cannot provide the same causal certainty as a placebo-controlled trial. Nevertheless, it is clinically relevant to patients for whom intermittent oral dosing no longer gives predictable coverage and who are not candidates for or do not want device-aided alternatives such as DBS. For HCPs, successful use requires patient and caregiver education, pump handling, skin-site management and monitoring for adverse effects. The study supports considering continuous dopaminergic delivery as part of an advanced Parkinson pathway rather than simply escalating oral doses.