Background: Lack of a global consensus on the definition of advanced Parkinson's disease (APD) and considerations for timing of device-aided therapies may result in heterogeneity in care.
Objectives: ...To reach consensus among movement disorder specialists regarding key patient characteristics indicating transition to APD and guiding appropriate use of device-aided therapies in the management of PD symptoms.
Methods: A Delphi-panel approach was utilized to synthesize opinions of movement disorder specialists and build consensus.
Results: A panel was comprised of movement disorder specialists from 10 European countries with extensive experience of treating PD patients (mean =24.8 ± 7.2 years). Consensus on indicators of suspected APD and eligibility for device-aided therapies were based on motor symptoms, non-motor symptoms, and functional impairments. Key indicators of APD included: (i) motor-moderate troublesome motor fluctuations, ≥1 h of troublesome dyskinesia/day, ≥2 h "off" symptoms/day, and ≥5-times oral levodopa doses/day; (ii) non-motor-mild dementia, and non-transitory troublesome hallucinations; (iii) functional impairment-repeated falls despite optimal treatment, and difficulty with activities of daily living. Patients with good levodopa response, good cognition, and <70 years of age were deemed as good candidates for all three device-aided therapies. Patients with troublesome dyskinesia were considered good candidates for both levodopa-carbidopa intestinal gel and Deep Brain Stimulation (DBS). PD patients with levodopa-resistant tremor were considered good candidates for DBS.
Conclusion: Identifying patients progressing to APD and suitable for device-aided therapies will enable general neurologists to assess the need for referral to movement disorder specialists and improve the quality of care and patient outcomes.
Summary Recent advances in structural and functional imaging have greatly improved our ability to assess normal functions of the basal ganglia, diagnose parkinsonian syndromes, understand the ...pathophysiology of parkinsonism and other movement disorders, and detect and monitor disease progression. Radionuclide imaging is the best way to detect and monitor dopamine deficiency, and will probably continue to be the best biomarker for assessment of the effects of disease-modifying therapies. However, advances in magnetic resonance enable the separation of patients with Parkinson's disease from healthy controls, and show great promise for differentiation between Parkinson's disease and other akinetic-rigid syndromes. Radionuclide imaging is useful to show the dopaminergic basis for both motor and behavioural complications of Parkinson's disease and its treatment, and alterations in non-dopaminergic systems. Both PET and MRI can be used to study patterns of functional connectivity in the brain, which is disrupted in Parkinson's disease and in association with its complications, and in other basal-ganglia disorders such as dystonia, in which an anatomical substrate is not otherwise apparent. Functional imaging is increasingly used to assess underlying pathological processes such as neuroinflammation and abnormal protein deposition. This imaging is another promising approach to assess the effects of treatments designed to slow disease progression.
All patients were in early stages of disease, and not all were on levodopa at study entry. Because the study was exploratory, no correction was made for multiple comparisons. ...α-synuclein plays a ...part in regulation of neurotransmitter release and in synaptic plasticity and learning, and it will therefore be important to do long-term monitoring of patients to see if there are unanticipated deleterious effects related to the loss of the physiological function of α-synuclein. Science Photo Library AJS receives honoraria as chair of the data safety monitoring board for a trial (Voyager, Neurocrine Biosciences) of AADC gene therapy for Parkinson's disease and has received a speaker honorarium from AbbVie.
Trials of GDNF in Parkinson's disease have yielded inconsistent results. In a randomised controlled trial, Whone et al. administer GDNF using a paradigm designed to optimize delivery to the putamen. ...18FDOPA PET reveals putamen-wide uptake, but GDNF does not differ from placebo in its effects on motor function.
Abstract
We investigated the effects of glial cell line-derived neurotrophic factor (GDNF) in Parkinson's disease, using intermittent intraputamenal convection-enhanced delivery via a skull-mounted transcutaneous port as a novel administration paradigm to potentially afford putamen-wide therapeutic delivery. This was a single-centre, randomized, double-blind, placebo-controlled trial. Patients were 35-75 years old, had motor symptoms for 5 or more years, and presented with moderate disease severity in the OFF state Hoehn and Yahr stage 2-3 and Unified Parkinson's Disease Rating Scale motor score (part III) (UPDRS-III) between 25 and 45 and motor fluctuations. Drug delivery devices were implanted and putamenal volume coverage was required to exceed a predefined threshold at a test infusion prior to randomization. Six pilot stage patients (randomization 2:1) and 35 primary stage patients (randomization 1:1) received bilateral intraputamenal infusions of GDNF (120 µg per putamen) or placebo every 4 weeks for 40 weeks. Efficacy analyses were based on the intention-to-treat principle and included all patients randomized. The primary outcome was the percentage change from baseline to Week 40 in the OFF state (UPDRS-III). The primary analysis was limited to primary stage patients, while further analyses included all patients from both study stages. The mean OFF state UPDRS motor score decreased by 17.3 ± 17.6% in the active group and 11.8 ± 15.8% in the placebo group (least squares mean difference: −4.9%, 95% CI: −16.9, 7.1, P = 0.41). Secondary endpoints did not show significant differences between the groups either. A post hoc analysis found nine (43%) patients in the active group but no placebo patients with a large clinically important motor improvement (≥10 points) in the OFF state (P = 0.0008). 18F-DOPA PET imaging demonstrated a significantly increased uptake throughout the putamen only in the active group, ranging from 25% (left anterior putamen; P = 0.0009) to 100% (both posterior putamina; P < 0.0001). GDNF appeared to be well tolerated and safe, and no drug-related serious adverse events were reported. The study did not meet its primary endpoint. 18F-DOPA imaging, however, suggested that intermittent convection-enhanced delivery of GDNF produced a putamen-wide tissue engagement effect, overcoming prior delivery limitations. Potential reasons for not proving clinical benefit at 40 weeks are discussed.
PDF
