Jost, Wolfgang H.Bergquist, FilipEvans, AndrewHassin-Baer, SharonHauser, Robert A.Henriksen, ToveMalaty, Irene A.Mestre, Tiago A.Mir, PabloRodriguez, RamonSchwingenschuh, PetraSimu, MihaelaBergmann, LarsZhou, Teresa T.Caughlin, SarahGopalkrishnan, MallikaKukreja, PavnitO’Meara, MarieParra, Juan C.Shah, Megha B.Aldred, Jason2026-05-122026-05-122026-05-07https://doi.org/10.1007/s40120-026-00948-6http://hdl.handle.net/10393/51631Abstract Introduction Foslevodopa/foscarbidopa (LDp/CDp) is a nonsurgical 24-h continuous subcutaneous infusion for patients with advanced Parkinson’s disease (aPD) and motor fluctuations uncontrolled on oral medications. We present the first multicountry real-world data from routine clinical practice. Methods ROSSINI (NCT06107426) is an ongoing 3-year multicountry, prospective, observational study of adults with aPD who are LDp/CDp-naïve (cohort A) or transitioning from LDp/CDp open-label extension studies (NCT04379050/NCT04750226, cohort B). For this interim analysis, the primary endpoint was change from baseline to 6 months in OFF time [Movement Disorder Society Unified Parkinson’s Disease Rating Scale Part IV (MDS-UPDRS-IV) modified item 4.3]. Safety was assessed by monitoring adverse events (AEs). Interim results for 105 cohort A patients enrolled ≥ 6 months by March 24, 2025 are presented only; cohort B results were limited (n = 5). Mixed-effects models for repeated measurements (continuous outcomes) were utilized, adjusted for country. Results Cohort A patients had a mean (SD) age of 68.5 (9.5) years, PD duration of 12.1 (5.3) years, and least squares mean (SE) OFF time of 5.2 (0.6) h at baseline. Patients on LDp/CDp showed statistically significant reductions (95% CI) in OFF time [(− 2.8 h (− 3.6, − 1.9), P ≤ .001, n = 47/40 at baseline/month 6], dyskinesia time [− 1.8 h (− 2.6, − 0.9), P ≤ 0.001], MDS-UPDRS-III [− 5.0 (− 8.2, − 1.9), P = 0.002], Parkinson’s Disease Sleep Scale-2 [− 5.2 (− 8.0, − 2.4), P ≤ .001], and 39-item Parkinson’s Disease Questionnaire [PDQ-39, − 5.6 (− 9.2, − 2.0), P = .002] from baseline to month 6. Freezing of Gait Questionnaire, Gastrointestinal Dysfunction Scale in PD, and King’s PD Pain Scale likewise showed statistically significant decreases (P < .05). Overall, 58 (55.2%) reported ≥ 1 AE, primarily nonserious and mild-to-moderate (12.4% serious, 17.1% severe), with hallucinations and infusion site events the most frequently reported events (5.7% each). Conclusions ROSSINI demonstrates reductions in motor fluctuations and nonmotor symptoms, and increased quality of life in patients with aPD after 6 months of LDp/CDp treatment. The safety profile was consistent with clinical trials. Trial registration ClinicalTrials.gov identifier, NCT06107426.Plain Language Summary Foslevodopa/foscarbidopa (LDp/CDp) treatment provides continuous medication through a pump that infuses medicine under the skin for people with advanced Parkinson’s disease whose motor symptoms are not managed well by oral medications. This study reports global data gathered during routine medical practices. The ROSSINI study is a 3-year observational project involving patients with advanced Parkinson’s disease and includes adults who are either new to LDp/CDp treatment (group A) or continuing their treatment from previous studies (group B). The main goal is to observe changes in the daily hours patients experience recurring motor symptoms (OFF time) over 36 months. Patient safety is monitored through reported side effects. This article shares interim findings for 105 group A patients enrolled for at least 6 months. Group A patients had an average age of 68.5 years, a Parkinson’s disease duration of about 12 years, and approximately 5.2 daily hours of OFF time. The study shows that LDp/CDp significantly reduced daily OFF time after 6 months, with improvements in disease-specific sleep, pain and gut issues, and overall quality of life. About half of patients reported at least one mild-to-moderate side effect, with some severe or serious; hallucinations and skin reactions were the most common side effects. These preliminary results suggest that LDp/CDp effectively improves both motor and nonmotor symptoms, enhancing patients' quality of life, and is safe for use in routine care.Journal Article2026-05-12enThe Author(s)