AbbVie’s ROSSINI (NCT06107426) study of its Parkinson’s disease combination, Vyalev, has shown promise in a 12-month analysis.
The data, which was presented on 29 June at the 12th Congress of the European Academy of Neurology (EAN) 2026, supported the safety and effectiveness of Vyalev (foslevodopa/foscarbidopa [LDp/CDp]), a nonsurgical, 24-hour/day continuous subcutaneous infusion therapy for patients with advanced Parkinson’s disease whose motor fluctuations remain inadequately controlled with oral medications.
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The ROSSINI study is an ongoing, three-year, multi-country, prospective observational study evaluating the long-term safety and effectiveness of Vyalev in routine clinical practice. The current interim analysis focused on cohort A, which included patients naïve to Vyalev treatment who had at least 12 months of follow-up. Overall, baseline characteristics reflected a clinically advanced Parkinson’s disease population, with a mean age of 68.1 years, mean duration of 12.1 years, mean OFF time of 4.8 hours, and mean dyskinesia time of 3.2 hours.
The results demonstrated sustained reductions in motor fluctuations over 12 months of Vyalev treatment. Daily OFF time decreased from 5.2 hours at baseline to 3.0 hours at month 12, representing a least-squares mean change of -2.2 hours. Dyskinesia time also decreased from 3.5 hours at baseline to 1.8 hours at month 12, with a least-squares mean change of -1.7 hours. These improvements were observed early, by week two, and were generally maintained through month 12, suggesting that Vyalev may provide durable symptom control in a real-world treatment setting.
Importantly, improvements were not limited to motor fluctuations. Patients also experienced sustained reductions across several nonmotor and disease-specific symptom measures, including Parkinson’s disease-related sleep disturbances, pain, gastrointestinal dysfunction, and freezing of gait. The largest changes were observed in Parkinson’s disease-related pain and sleep disturbance, with both outcomes exceeding reported minimal clinically important difference thresholds. These findings are notable because non-motor symptoms are a major driver of reduced quality of life in advanced Parkinson’s disease and are often difficult to manage with conventional oral regimens.
Quality-of-life findings were more nuanced. In the overall cohort, the 39-item Parkinson’s Disease Questionnaire summary index improved modestly from baseline to month 12. However, a subgroup of younger patients with shorter disease duration showed a larger numerical and statistically significant improvement, with scores decreasing from 31.3 at baseline to 24.0 at month 12. This may suggest that earlier use of continuous subcutaneous levodopa-based therapy, before more prolonged disease progression, could offer greater patient-perceived benefit, although this subgroup finding should be interpreted cautiously given the smaller patient numbers.
From a treatment-delivery perspective, Vyalev infusion rates increased moderately during the first month and then remained relatively stable throughout the study, while daily levodopa equivalent dose remained broadly stable. This supports the practical feasibility of maintaining patients on a relatively consistent dosing regimen after initial optimisation, which is important for real-world adoption and long-term patient management.
The safety profile remained consistent with expectations for a continuous subcutaneous infusion therapy. Any adverse event was reported in 74.1% of patients, severe adverse events in 22.9%, serious adverse events in 28.4%, and adverse events leading to withdrawal in 11.4%. The most frequently reported treatment-emergent adverse events were infusion-site infection, infusion-site reaction, and hallucinations. Six deaths were reported, all of which were considered unrelated to the study treatment. Overall, the safety findings appear consistent with the known clinical experience of Vyalev and highlight infusion-site management as an important consideration in routine care.
These interim findings strengthen the real-world evidence base for Vyalev as a non-surgical device-aided treatment option for advanced Parkinson’s disease. The ability to provide continuous levodopa delivery without intestinal surgery may be an important differentiator versus more invasive device-aided approaches, particularly for patients who require more stable symptom control but may be less suitable for surgical intervention.
However, interpretation of the data is limited by the observational study design, potential confounding, and reliance on self-reported assessments. In addition, missing OFF time and dyskinesia time data in more than 50 patients due to a technical issue may affect interpretation of some motor fluctuation outcomes, although item scores themselves were not affected.
Overall, the ROSSINI 12-month interim results support Vyalev as a clinically meaningful real-world treatment option for advanced Parkinson’s disease, demonstrating sustained improvements in motor fluctuations, non-motor symptoms, and selected quality-of-life outcomes over one year. Continued follow-up will be important to confirm the durability of benefit, better characterise long-term safety, and clarify which patient subgroups may derive the greatest treatment value.
