Non-oral dopaminergic therapies for Parkinson's disease: current treatments and the future

Non-oral continuous drug delivery based therapies and sleep dysfunction in Parkinson's disease

Continuous drug delivery (CDD) has emerged as a feasible and pragmatic therapeutic option for dopamine replacement therapy in advanced Parkinson's disease (PD). CDD aims to mimic the physiological tonic dopamine release from striatal dopaminergic neurons and thus reduces the severity and duration of motor and non-motor fluctuations partly related to pulsatile levodopa stimulation. Non-motor symptoms and fluctuations are ubiquitous in PD and include sleep dysfunction, a problem that occurs in over 90% of PD patients across all stages, from prodromal to palliative. In this review, we discuss the currently available and in development non-oral dopaminergic CDD strategies with a focus on their efficacy in the treatment of the burdensome sleep dysfunction in PD.

Rating Scales for Medication Adherence in Parkinson's Disease: A Systematic Review for Critique and Recommendations

Background

Behaviors interfering with medication adherence (MA) are common and often complex in Parkinson's disease (PD), negatively affecting quality of life and undermining the value of clinical trials. The Clinical Outcome Assessments (COA) Scientific Evaluation Committee of the International Parkinson and Movement Disorder Society (MDS) commissioned the assessment of MA rating scales to recommend the use in PD.

Objective

Critically review the measurement properties of rating scales used to assess MA in PD and to issue recommendations.

Methods

We conducted systematic review across seven databases to identify structured scales to assess MA in PD. Eligible studies were critically appraised for methodological quality using the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) Risk of Bias checklist. Standards for good measurement properties of the selected scales were summarized narratively using the COSMIN, the MDS-COA Committee methodology, the World Health Organization concepts, and the Ascertaining Barriers to Compliance taxonomy. The certainty of the evidence was determined using the modified Grades of Recommendation, Assessment, Development and Evaluation approach with final assessments (highest to lowest) of "Recommended," "Suggested" and "Listed".

Results

Of the nine reviewed scales, none met the designation "Recommended". The Morisky Medication Adherence Scale (MMAS-8); Beliefs Related to Medications Adherence questionnaire, Beliefs about Medication Questionnaire, Medication Adherence Rating Scale, and Satisfaction with Information on Medicines Scale were rated "Suggested".

Conclusions

We suggest further work focusing on resolving the problems of the suggested scales or developing a new scale meeting all required criteria.

Advances in the Pharmacological and Non-pharmacological Management of Non-motor Symptoms in Parkinson's Disease: An Update Since 2017

BACKGROUND

Non-motor symptoms (NMS) are an important and ubiquitous determinant of quality of life in Parkinson's disease (PD). However, robust evidence for their treatment is still a major unmet need.

OBJECTIVE

This study aimed to provide an updated review on advances in pharmacological, nonpharmacological, and exercise-based interventions for NMS in PD, covering the period since the publication of the MDS Task Force Recommendations.

METHODS

We performed a literature search to identify pharmacological, non-pharmacological, and exercise-based interventions for NMS in PD. As there are recent reviews on the subject, we have only included studies from the 1st of January 2017 to the 1st of December 2021 and limited our search to randomised and non-randomised (including open-label) clinical trials.

RESULTS

We discuss new strategies to manage NMS based on data that have become available since 2017, for instance, on the treatment of orthostatic hypotension with droxidopa, several dopaminergic treatment options for insomnia, and a range of non-pharmacological and exercise-based interventions for cognitive and neuropsychiatric symptoms, pain, and insomnia and excessive sleepiness.

CONCLUSION

Recent evidence suggests that targeted non-pharmacological treatments, as well as some other NMS management options, may have a significant beneficial effect on the quality of life and need to be considered in the pathways of treatment of PD.

Why do 'OFF' periods still occur during continuous drug delivery in Parkinson's disease?

Continuous drug delivery (CDD) is used in moderately advanced and late-stage Parkinson’s disease (PD) to control motor and non-motor fluctuations (‘OFF’ periods). Transdermal rotigotine is indicated for early fluctuations, while subcutaneous apomorphine infusion and levodopa-carbidopa intestinal gel are utilised in advanced PD. All three strategies are considered examples of continuous dopaminergic stimulation achieved through CDD. A central premise of the CDD is to achieve stable control of the parkinsonian motor and non-motor states and avoid emergence of ‘OFF’ periods. However, data suggest that despite their efficacy in reducing the number and duration of ‘OFF’ periods, these strategies still do not prevent ‘OFF’ periods in the middle to late stages of PD, thus contradicting the widely held concepts of continuous drug delivery and continuous dopaminergic stimulation. Why these emergent ‘OFF’ periods still occur is unknown. In this review, we analyse the potential reasons for their persistence. The contribution of drug- and device-related involvement, and the problems related to site-specific drug delivery are analysed. We propose that changes in dopaminergic and non-dopaminergic mechanisms in the basal ganglia might render these persistent ‘OFF’ periods unresponsive to dopaminergic therapy delivered via CDD.

Management of dysphagia and gastroparesis in Parkinson’s disease in real-world clinical practice – Balancing pharmacological and non-pharmacological approaches

Gastrointestinal (GI) issues are commonly experienced by patients with Parkinson’s disease (PD). Those that affect the lower GI tract, such as constipation, are the most frequently reported GI problems among patients with PD. Upper GI issues, such as swallowing dysfunction (dysphagia) and delayed gastric emptying (gastroparesis), are also common in PD but are less well recognized by both patients and clinicians and, therefore, often overlooked. These GI issues may also be perceived by the healthcare team as less of a priority than management of PD motor symptoms. However, if left untreated, both dysphagia and gastroparesis can have a significant impact on the quality of life of patients with PD and on the effectiveness on oral PD medications, with negative consequences for motor control. Holistic management of PD should therefore include timely and effective management of upper GI issues by utilizing both non-pharmacological and pharmacological approaches. This dual approach is key as many pharmacological strategies have limited efficacy in this setting, so non-pharmacological approaches are often the best option. Although a multidisciplinary approach to the management of GI issues in PD is ideal, resource constraints may mean this is not always feasible. In ‘real-world’ practice, neurologists and PD care teams often need to make initial assessments and treatment or referral recommendations for their patients with PD who are experiencing these problems. To provide guidance in these cases, this article reviews the published evidence for diagnostic and therapeutic management of dysphagia and gastroparesis, including recommendations for timely and appropriate referral to GI specialists when needed and guidance on the development of an effective management plan.

Closing the loop for patients with Parkinson disease: where are we?

Although levodopa remains the most efficacious symptomatic therapy for Parkinson disease (PD), management of levodopa treatment during the advanced stages of the disease is extremely challenging. This difficulty is a result of levodopa's short half-life, a progressive narrowing of the therapeutic window, and major inter-patient and intra-patient variations in the dose-response relationship. Therefore, a suitable alternative to repeated oral administration of levodopa is being sought. Recent research efforts have focused on the development of novel levodopa delivery strategies and wearable physical sensors that track symptoms and disease progression. However, the need for methods to monitor the levels of levodopa present in the body in real time has been overlooked. Advances in chemical sensor technology mean that the development of wearable and mobile biosensors for continuous or frequent levodopa measurements is now possible. Such levodopa monitoring could help to deliver personalized and timely medication dosing to alleviate treatment-related fluctuations in the symptoms of PD. Therefore, with the aim of optimizing therapeutic management of PD and improving the quality of life of patients, we share our vision of a future closed-loop autonomous wearable 'sense-and-act' system. This system consists of a network of physical and chemical sensors coupled with a levodopa delivery device and is guided by effective big data fusion algorithms and machine learning methods.

Mechanisms of peripheral levodopa resistance in Parkinson's disease

Parkinson’s disease (PD) is an increasingly common neurodegenerative condition. The disease has a significant negative impact on quality of life, but a personalized management approach can help reduce disability. Pharmacotherapy with levodopa remains the cornerstone of treatment, and a gratifying and sustained response to this treatment is a supportive criterion that argues in favor of an underlying diagnosis of PD. Yet, in daily practice, it is not uncommon to encounter patients who appear to have true PD, but who nevertheless seem to lose the responsiveness to levodopa (secondary non-responders). Some patients may even fail to respond altogether (primary non-responders). Here, we address how two mechanisms of “peripheral resistance” may underlie this failing response to levodopa in persons with PD. The first explanation relates to impaired bowel motility leading to secondary bacterial overgrowth, and more specifically, to the excessive bacterial production of the enzyme tyrosine decarboxylase (TDC). This enzyme may convert levodopa to dopamine in the gut, thereby hampering entry into the circulation and, subsequently, into the brain. The second explanation relates to the systemic induction of the enzyme aromatic l-amino acid decarboxylase (AADC), leading to premature conversion of levodopa into dopamine, again limiting the bioavailability within the brain. We discuss these two mechanisms and focus on the clinical implications, potential treatments and directions for future research.

Tolerability of overnight rotigotine transdermal patch combined with intrajejunal levodopa infusion at 1 year: a 24-h treatment option in Parkinson's disease

Background

Twenty-four-hour treatment options could provide a continuous drug delivery strategy in advanced Parkinson’s disease and can ameliorate motor and non-motor complications. Use of levodopa infusion is often limited to 12–16 h/day due to its cost. Adjunctive overnight rotigotine transdermal patch is a continuous drug delivery option successfully used in clinical practice coupled with apomorphine infusion. However, real-life data addressing the tolerability of transdermal dopamine agonist therapy with concomitant use of intrajejunal levodopa infusion in advanced Parkinson’s disease are not available.

Objective

To evaluate the tolerability and beneficial effects of combined therapy with overnight rotigotine transdermal patch and intrajejunal levodopa infusion over a follow-up period of 12 months in advanced Parkinson’s disease.

Method

In this retrospective data analysis, data before and after the initiation of the continuous drug delivery combined therapy using overnight rotigotine transdermal patch and intrajejunal levodopa infusion were collected from the ongoing non-motor-international-longitudinal study (NILS) and local clinical practice at King’s College Hospital (London, United Kingdom). 12 advanced Parkinson’s disease patients on intrajejunal levodopa therapy who were additionally treated with overnight rotigotine transdermal patch (mean dose 5.67 ± 4.19 mg) are included. Tolerability over a 12-month period was assessed. In addition, changes in motor symptoms (SCales for Outcomes in Parkinson's disease, SCOPA-Motor), non-motor symptoms (Non-Motor Symptoms Scale, NMSS) and quality of life (Parkinson's disease Questionnaire-8, PDQ-8) before and 12-month after continuous drug delivery combined therapy initiation are evaluated.

Results

Tolerability was 100% irrespective of age, disease duration, stages of disease. (Treatment with overnight rotigotine transdermal patch that was maintained for a minimum of 6 months was considered “tolerated”, primary tolerability). In addition, we noted a significant reduction of the NMSS total score (p = 0.009) and the NMSS domain 3 score (mood and apathy domain) (p = 0.028), although the latter did not remain statistically significant after correction for multiple testing (p2 = 0.252) at 12 months.

Conclusion

Combination of intrajejunal levodopa infusion with overnight rotigotine transdermal patch is well tolerated and extend the beneficial effects of infusion with excellent tolerability; and also improved aspects of mood and apathy sustained at 12 months in advanced Parkinson’s disease.

Multifunctional Therapeutic Approach of Nanomedicines against Inflammation in Cancer and Aging

Cancer is a fatal disorder that affects people across the globe, yet existing therapeutics are ineffective. The development of submicrometer transport for optimizing the biodistribution of systemically provided medications is the focus of nanomedicine. Nanoparticle- (NP-) based treatments may enable the development of novel therapeutic approaches to combat this deadly disorder. In multifunctional, multimodal imaging, and drug delivery carriers, NPs generally play a major role. They have emerged as potential strategies for the invention of innovative therapeutic procedures in the last decade. The exponential growth of nanotechnologies in recent years has increased public awareness of the application of these innovative therapeutic approaches. Many tumor-targeted nanomedicines have been studied in cancer therapy, and there is clear evidence for a significant improvement in the therapeutic index of antineoplastic drugs. Age-related factors such as metabolic and physiological alterations in old age and inadequate animal models are currently understudied in nanomedicine and pharmacology. This review highlighted the most important targeting approaches, as well as public awareness, therapeutic advancements, and future prospects in age-related metabolic variations, and tumor-targeted nanomedicine studies.

New approaches to treatments for sleep, pain and autonomic failure in Parkinson's disease - Pharmacological therapies

Non-motor symptoms (NMSs) are highly prevalent throughout the course of Parkinson's disease (PD). Pain, autonomic dysfunction and sleep disturbances remain at the forefront of the most common NMSs; their treatment is challenging and their effect on the quality of life of both patients and caregivers detrimental. Yet, the landscape of clinical trials in PD is still dominated by therapeutic strategies seeking to ameliorate motor symptoms; subsequently, effective strategies to successfully treat NMSs remain a huge unmet need. Wider awareness among industry and researchers is thus essential to give rise to development and delivery of high-quality, large-scale clinical trials in enriched populations of patients with PD-related pain, autonomic dysfunction and sleep. In this review, we discuss recent developments in the field of pharmacological treatment strategies designed or re-purposed to target three key NMSs: pain, autonomic dysfunction and sleep disturbances. We focus on emerging evidence from recent clinical trials and outline some exciting and intriguing findings that call for further investigations.

Designing nanoformulation for the nose-to-brain delivery in Parkinson's disease: Advancements and barrier

Parkinson's disease (PD), a neurodegenerative disorder characterized by the degeneration of dopaminergic neurons, which results in the loss of motor activity. In the management of PD, the primary aim is to increase the dopamine content in the brain either by delivering the precursors of dopamine or by inhibiting the molecules responsible for dopamine degradation. Due to the low bioavailability, a higher dosage of drugs needs to be administered repeatedly for achieving the desired therapeutic effect. This repeated high dose not only increases the severe side effects but also produces tolerance in the body. Often, direct administration of drugs fails to ameliorate the symptoms as the unmodified drugs cannot cross the blood-brain barrier (BBB). Nanotherapeutic is at the forefront of the alternative treatment against the central nervous system (CNS) disorders due to the ability to circumvents the BBB. Here, all the available treatments for PD have been discussed with their limitation. The current trends of nanotherapeutics for PD have been explored. Suitability and formulation prospects for nasal delivery have been analyzed in detail to explore new research scope. The most effective approach is the nose-to-brain delivery for targeting drugs directly to the brain. This delivery bypasses the BBB and concentrates more drugs at the target site. Thus, developments of nose-to-brain delivery of nanoformulations explicit the new scope to manage PD better. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Effects of Levodopa-Carbidopa Intestinal Gel on Dyskinesia and Non-Motor Symptoms Including Sleep: Results from a Meta-Analysis with 24-Month Follow-Up

BACKGROUND

In advanced Parkinson's disease (PD), dyskinesias and non-motor symptoms such as sleep dysfunction can significantly impair quality of life, and high-quality management is an unmet need.

OBJECTIVE

To analyze changes in dyskinesia and non-motor symptoms (including sleep) among studies with levodopa-carbidopa intestinal gel (LCIG) in patients with advanced PD.

METHODS

A comprehensive literature review identified relevant studies examining LCIG efficacy. Outcomes of interest were dyskinesia (UDysRS, UPDRS IV item 32), overall non-motor symptoms (NMSS), mentation/behavior/mood (UPDRS I), and sleep/daytime sleepiness (PDSS-2, ESS). The pooled mean (95% confidence interval) change from baseline per outcome was estimated for each 3-month interval with sufficient data (i.e., reported by≥3 studies) up to 24 months using a random-effects model.

RESULTS

Seventeen open-label studies evaluating 1243 patients with advanced PD were included. All outcomes of interest with sufficient data for meta-analysis showed statistically significant improvement within 6 months of starting LCIG. There were statistically significant improvements in dyskinesia duration as measured by UPDRS IV item 32 at 6 months (-1.10 [-1.69, -0.51] h/day) and 12 months (-1.35 [-2.07, -0.62] h/day). There were statistically and clinically significant improvements in non-motor symptoms as measured by NMSS scores at 3 months (-28.71 [-40.26, -17.15] points). Significant reduction of NMSS burden was maintained through 24 months (-17.61 [-21.52, -13.70] points). UPDRS I scores significantly improved at 3 months (-0.39 [-0.55, -0.22] points). Clinically significant improvements in PDSS-2 and ESS scores were observed at 6 and 12 months in individual studies.

CONCLUSION

Patients with advanced PD receiving LCIG showed significant sustained improvements in the burden of dyskinesia and non-motor symptoms up to 24 months after initiation.

Nocturnal Sleep Problems Mediate the Impact on Quality of Life of Early Morning Off in Parkinson's Disease

Background: Early morning off (EMO) refers to off-states in the morning in people diagnosed with Parkinson's disease (PwPD). This study determined the clinical manifestations of EMO and the association with nocturnal sleep problems and quality of life (QOL) in Chinese PwPD.

Methods: In this multicenter, observational, cross-sectional study, data concerning the clinical manifestations of EMO were collected from PwPD in Shanghai by questionnaire. The stepwise logistic regression was performed to analyze the potential risk factors, as well as whether EMO was an independent risk factor for functional dependency in daily life. The mediation analyses were conducted to evaluate whether nocturnal sleep problems might mediate the association between EMO and the QOL.

Results: Among the 454 subjects evaluated, EMO occurred in 39.43% of PwPD across all disease stages. The prevalence of EMO increased as the Hoehn and Yahr stage increased and was observed in 35.60% of patients in stages 1–2.5 and 48.85% of patients in stages 3–5. EMO was associated with non-motor symptoms (NMSs). The predominant NMSs associated with EMO were nocturnal sleep problems (98.90%), mood/cognition impairment (93.90%), decreased attention/memory (91.60%), gastrointestinal symptoms (91.60%), and urinary urgency (90.50%). The QOL of PwPD with EMO was significantly reduced (P < 0.001). Moreover, nocturnal sleep problems might partially mediate this relationship (indirect effect: β = 13.458, 95% boot CI: 6.436, 22.042).

Conclusion: PwPD have EMO throughout all stages of the disease. Patients with EMO have severe motor symptoms and NMSs. EMO decreases the QOL in PwPD and this relationship is partially mediated by nocturnal sleep problems. In light of these findings, it is suggested that recognition and appropriate treatment of EMO and nocturnal sleep problems could improve the management of PwPD.

Implications of dopaminergic medication withdrawal in Parkinson's disease

The trajectory of the use of dopamine replacement therapy (DRT) in Parkinson's disease (PD) is variable and doses may need to be increased, but also tapered. The plan for dose adjustment is usually done as per drug information recommendations from the licensing bodies, but there are no clear guidelines with regards to the best practice regarding the tapering off schedule given sudden dose reductions of drugs such as dopamine agonists may have serious adverse consequences. A systematic literature search was, therefore, performed to derive recommendations and the data show that there are no controlled studies or evidence-based recommendations how to taper or discontinue PD medication in a systematic manner. Most of the data were available on the dopamine agonist withdrawal syndrome (DAWS) and we found only two instructions on how to reduce pramipexole and rotigotine published by the EMA. We suggest that based on the available data, levodopa, dopamine agonists (DA), and amantadine should not be discontinued abruptly. Abrupt or sudden reduction of DA or amantadine in particular can lead to severe life-threatening withdrawal symptoms. Tapering off levodopa, COMT inhibitors, and MAO-B inhibitors may worsen motor and non-motor symptoms. Based on our clinical experience, we have proposed how to reduce PD medication and this work will form the basis of a future Delphi panel to define the recommendations in a consensus.

Personalized Medicine in Parkinson's Disease: New Options for Advanced Treatments

Parkinson’s disease (PD) presents varying motor and non-motor features in each patient owing to their different backgrounds, such as age, gender, genetics, and environmental factors. Furthermore, in the advanced stages, troublesome symptoms vary between patients due to motor and non-motor complications. The treatment of PD has made great progress over recent decades and has directly contributed to an improvement in patients’ quality of life, especially through the progression of advanced treatment. Deep brain stimulation, radiofrequency, MR–guided focused ultrasound, gamma knife, levodopa-carbidopa intestinal gel, and apomorphine are now used in the clinical setting for this disease. With multiple treatment options currently available for all stages of PD, we here discuss the most recent options for advanced treatment, including cell therapy in advanced PD, from the perspective of personalized medicine.

Prevention of MEK-ERK-1/2 hyper-activation underlines the neuroprotective effect of Glycyrrhiza glabra L. (Yashtimadhu) against rotenone-induced cellular and molecular aberrations

ETHNOPHARMACOLOGICAL RELEVANCE

Yashtimadhu choorna (powder) is prepared from the dried root of Glycyrrhiza glabra L., commonly known as licorice. The Indian Ayurvedic system classifies Yashtimadhu as a Medhya Rasayana that can enhance brain function, improves memory, and possess neuroprotective functions, which can be used against neurodegenerative diseases like Parkinson's disease (PD).

AIM OF THE STUDY

We aimed to decipher the neuroprotective effects of G. glabra L., i.e., Yashtimadhu, in a rotenone-induced PD model.

MATERIALS AND METHODS

Retinoic acid-differentiated IMR-32 cells were treated with rotenone (PD model) and Yashtimadhu, and were assessed for cellular toxicity, live-dead staining, cell cycle, oxidative stress, protein abundance, and kinase phosphorylation.

RESULTS

Yashtimadhu conferred protection against rotenone-induced cytotoxicity, countered cell death, reduced expression of pro-apoptotic proteins (cleaved-caspases-9, and 3, cleaved-PARP, BAX, and BAK) and increased anti-apoptotic protein, BCL-2. Rotenone-induced cell cycle re-entry (G2/M transition), was negated by Yashtimadhu and was confirmed with PCNA levels. Yashtimadhu countered rotenone-mediated activation of mitochondrial proteins involved in oxidative stress, cytochrome-C, PDHA1, and HSP60. Inhibition of rotenone-induced ERK-1/2 hyperphosphorylation prevented activation of apoptosis, which was confirmed with MEK-inhibitor, highlighted the action of Yashtimadhu via ERK-1/2 modulation.

CONCLUSIONS

We provide the evidence for neuroprotection conferred by G. glabra L. (Yashtimadhu) and its mechanism via inhibiting MEK-ERK-1/2 hyper-phosphorylation, prevention of mitochondrial stress, and subsequent prevention of apoptosis. The study highlights Yashtimadhu as a promising candidate with neuroprotective effects, the potential of which can be harnessed for identifying novel therapeutic targets.

Living with Parkinson’s disease and connected to the duodopa pump: A qualitative study

Parkinson’s Disease (PD) is a complex and heterogeneous disease that has a major impact on the lives of patients and their family caregivers. The duodopa pump is one of the treatments options for advanced PD. The experience of patients with this treatment is largely unexplored, however. This study is based on the experiences of patients with PD as well as their family caregivers using the pump. We take a multimodal approach that includes narrative semi-structured interviews and drawings. This methodology helps participants, particularly those with difficulty articulating themselves, express their experience with the disease and their perception of the treatment. We believe that the use of drawings complementing semi-structured interviews offers additional insights into the participants’ perception of PD and the pump. In this article we focus on the following topics: the participants’ perception of PD and the pump, the reasons for choosing the pump over alternatives, and the advantages and disadvantages of this treatment for patients and family caregivers. Our findings show that the participants consider PD as a complex and unpredictable disease that changed their lives and affect everyone differently, while the pump makes the disease less changeable and more manageable.

Rotigotine Transdermal Patch for Motor and Non-motor Parkinson's Disease: A Review of 12 Years' Clinical Experience

Motor and non-motor symptoms (NMS) have a substantial effect on the health-related quality of life (QoL) of patients with Parkinson's disease (PD). Transdermal therapy has emerged as a time-tested practical treatment option, and the rotigotine patch has been used worldwide as an alternative to conventional oral treatment for PD. The efficacy of rotigotine on motor aspects of PD, as well as its safety and tolerability profile, are well-established, whereas its effects on a wide range of NMS have been described and studied but are not widely appreciated. In this review, we present our overall experience with rotigotine and its tolerability and make recommendations for its use in PD and restless legs syndrome, with a specific focus on NMS, underpinned by level 1-4 evidence. We believe that the effective use of the rotigotine transdermal patch can address motor symptoms and a wide range of NMS, improving health-related QoL for patients with PD. More specifically, the positive effects of rotigotine on non-motor fluctuations are also relevant. We also discuss the additional advantages of the transdermal application of rotigotine when oral therapy cannot be used, for instance in acute medical emergencies or nil-by-mouth or pre/post-surgical scenarios. We highlight evidence to support the use of rotigotine in selected cases (in addition to general use for motor benefit) in the context of personalised medicine.

Improving the Delivery of Levodopa in Parkinson's Disease: A Review of Approved and Emerging Therapies

Levodopa is the most effective drug for the treatment of Parkinson's disease, but its use as an oral medication is complicated by its erratic absorption, extensive metabolism and short plasma half-life. On long-term use and with disease progression, there is a high incidence of motor and non-motor complications, which remain a major clinical and research challenge. It is widely accepted that levodopa needs to be administered using formulations that result in good and consistent bioavailability and the physiologically relevant and continuous formation of dopamine in the brain to maximise its efficacy while avoiding and reversing 'wearing off' and dyskinesia. However, the physicochemical properties of levodopa along with its pharmacokinetic and pharmacodynamic profile make it difficult to deliver the drug in a manner that fulfils these criteria. In this review, we examine the problems associated with the administration of levodopa in Parkinson's disease and how the use of novel technologies and delivery devices is leading to a more consistent and sustained levodopa delivery with the aim of controlling motor function as well as non-motor symptoms.

Gut Microbiota Approach-A New Strategy to Treat Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by neuronal loss and dysfunction of dopaminergic neurons located in the substantia nigra, which contain a variety of misfolded α-synuclein (α-syn). Medications that increase or substitute for dopamine can be used for the treatment of PD. Recently, numerous studies have shown gut microbiota plays a crucial role in regulating and maintaining multiple aspects of host physiology including host metabolism and neurodevelopment. In this review article, the role of gut microbiota in the etiological mechanism of PD will be reviewed. Furthermore, we discussed current pharmaceutical medicine-based methods to prevent and treat PD, followed by describing specific strains that affect the host brain function through the gut-brain axis. We explained in detail how gut microbiota directly produces neurotransmitters or regulate the host biosynthesis of neurotransmitters. The neurotransmitters secreted by the intestinal lumen bacteria may induce epithelial cells to release molecules that, in turn, can regulate neural signaling in the enteric nervous system and subsequently control brain function and behavior through the brain-gut axis. Finally, we proved that the microbial regulation of the host neuronal system. Endogenous α-syn can be transmitted long distance and bidirectional between ENS and brain through the circulatory system which gives us a new option that the possibility of altering the community of gut microbiota in completely new medication option for treating PD.

Role of sodium l-cysteine alginate conjugate and isopropyl myristate to enhance the permeation enhancing activity of BCS class III drug from TDDS; optimization by central composite design and in vivo pharmacokinetics study

OBJECTIVE

The objective of the present research was to study the effect and optimization of sodium alginate l-cysteine conjugate and permeation enhancer on permeation of high soluble low permeable ropinirole hydrochloride from the transdermal formulation.

METHODS

Sodium alginate l-cysteine conjugate was prepared and characterized and the same was added into a transdermal formulation along with IPM as a permeation enhancer. Twelve primary formulations were prepared by solvent casting method and evaluated. The results were fed into Design Expert® Software to obtain optimized formulation. The optimized formulation was evaluated for physicochemical, ex vivo permeation, stability, skin irritation, and pharmacokinetic studies.

RESULTS

The results of the characterization of prepared sodium alginate l-cysteine conjugate confirmed the thiolation process. Stability studies suggested that the drug was compatible with all the excipients. SEM images of the transdermal patch revealed that the amorphous drug was uniformly distributed. From the design space, the optimized formulation from the polymer's ratio (SA: SACC; 4:6) and IPM 9.5%w/w of polymers weight showed target steady state flux 9.004 µg/cm²/h with maximum drug permeation. The increased target flux and maximum drug permeation from an optimized patch suggested that there was an effect of SACC on ropinirole hydrochloride permeation in the presence of IPM as a permeation enhancer. Pharmacokinetic studies in rabbits showed that the optimized patch improved bioavailability as compared to marketed oral tablets.

CONCLUSIONS

The study was concluded that there was a positive effect of sodium alginate l-cysteine conjugate and IPM on ropinirole hydrochloride permeation from the transdermal formulation.

Establishing apomorphine treatment in Thailand: understanding the challenges and opportunities of Parkinson's disease management in developing countries

INTRODUCTION

The increasing global burden of Parkinson's disease (PD) poses a particular challenge for developing countries, such as Thailand, when delivering care to a geographically diverse populace with limited resources, often compounded by a lack of expertise in the use of certain PD medications, such as device-aided therapies (DAT).

AREAS COVERED

A panel of local, regional, and international PD experts convened to review the unmet needs of PD in Thailand and share insights into effective delivery of DAT, focusing on experience with apomorphine infusion. Despite its proven efficacy and safety, implementation of apomorphine infusion as a new option was not straightforward. This has prompted a range of health-care professional and patient-focused initiatives, led by the Chulalongkorn Center of Excellence for Parkinson's Disease and Related Disorders in Bangkok, to help establish a more coordinated approach to PD management throughout the country and ensure patients have access to suitable treatments.

EXPERT OPINION

Overcoming the challenges of education, proficiency, resource capacity and standard of care for PD patients in developing countries requires a coordinated effort both nationally and beyond. The best practices identified in Thailand following the introduction of apomorphine infusion might be helpful for other countries when implementing similar programs.

Ropinirole Patch Versus Placebo, Ropinirole Extended-Release Tablet in Advanced Parkinson's Disease

BACKGROUND

A dopamine agonist patch is an important treatment option for PD.

OBJECTIVES

A randomized, double-blind, parallel-group, placebo-controlled trial was conducted to evaluate superiority of ropinirole hydrochloride patch over placebo and noninferiority to ropinirole hydrochloride extended-release tablet.

METHODS

PD patients using levodopa received ropinirole patch (up to 64 mg/d), ropinirole tablets (up to 16 mg/d), or placebo once-daily (double-dummy technique). The primary endpoint was the change from baseline in the total score for the UPDRS Part III (on state) at week 16.

RESULTS

The change of the least squares mean (95% confidence interval) in the UPDRS Part III total score was -9.8 (-10.8 to -8.7) with ropinirole patch, -4.3 (-5.8 to -2.8) with placebo, and -10.1 (-11.2 to -9.1) with ropinirole tablet. The difference between the ropinirole patch and placebo groups was -5.4 (-7.3 to -3.6), demonstrating superiority of the patch over placebo. The difference between the ropinirole patch and tablet groups was 0.3 (-1.2 to 1.8). The upper limit of the 95% confidence interval was smaller than the noninferiority limit of 2.5, demonstrating noninferiority of ropinirole patch to ropinirole tablet. In all three groups, most adverse events were mild or moderate and there were no serious safety concerns.

CONCLUSIONS

Once-daily ropinirole patch was effective in advanced PD patients, having demonstrated superiority over placebo and noninferiority to ropinirole tablet, without causing serious safety problems. Ropinirole patch can be an alternative option for PD patients. © 2020 International Parkinson and Movement Disorder Society.

Clinical implications of gastric complications on levodopa treatment in Parkinson's disease

Disorders of the gastrointestinal (GI) tract are common and distressing nonmotor symptoms of Parkinson's disease (PD) that can adversely affect levodopa absorption and lead to OFF periods, also known as motor fluctuations. Gastroparesis, which is primarily defined as delayed gastric emptying (DGE), and Helicobacter pylori infection, which is present with increased frequency in PD, are among the most common and important GI disorders reported in PD that may impair oral levodopa absorption and increase OFF time. Symptoms of gastroparesis include nausea, vomiting, postprandial bloating, fullness, early satiety, abdominal pain, and weight loss. DGE has been reported in a substantial fraction of individuals with PD. Symptoms of H. pylori infection include gastritis and peptic ulcers. Studies have found that DGE and H. pylori infection are correlated with delayed peak levodopa plasma levels and increased incidence of motor fluctuations. Therapeutic strategies devised to minimize the potential that gastric complications will impair oral levodopa absorption and efficacy in PD patients include treatments that circumvent the GI tract, such as apomorphine injection, levodopa intestinal gel delivery, levodopa inhalation powder, and deep brain stimulation. Other strategies aim at improving gastric emptying in PD patients, primarily including prokinetic agents.

Apomorphine: The Initial Indian Experience in Relation to Response Tests and Pumps

Background:

Apomorphine is an option for continuous dopaminergic therapy in Parkinson's disease (PD). However, its effects in varied populations are limited due to its availability.

Objective:

To assess the efficacy and outcomes of apomorphine in Indian patients.

Materials and Methods:

Retrospective analysis of PD patients who underwent apomorphine response test (ART), along with the subset, who went on to apomorphine pumps.

Results:

Twenty-nine confirmed PD patients underwent ART and all PD patients showed good clinical response. 19 subjects developed adverse events which included: nausea (n-15, 51.7%), vomiting (n-10, 34.4%), sleepiness (n-08; 27.5%), yawning (n-07, 24.1%), postural hypotension (n-03, 10.3%), dizziness (n-03, 10.3%), and profuse sweating (n-01, 3.4%). Apomorphine pumps were initiated in six subjects, with significant clinical improvement. Adverse events on pump included subcutaneous nodules, nausea, hypersexuality. Two among them subsequently discontinued the pump primarily due to financial constraints.

Conclusions:

Apomorphine adds up to the armamentarium for treatment of PD patients in India with good clinical responses.

Continuous Drug Delivery Aiming Continuous Dopaminergic Stimulation in Parkinson's Disease

Continuous dopaminergic stimulation in Parkinson's disease (PD) has several advantages over pulsatile, non-continuous, stimulation. These therapies currently consist of pump-based and transcutaneous therapies and are based on a more constant delivery of the dopaminergic drug resulting in continuous dopaminergic stimulation and a more stable treatment effect. Several clinical and experimental observations have shown that continuous stimulation of dopaminergic receptors induces fewer complications, such as dyskinesia, compared to pulsatile stimulation. Currently available non-oral pharmacological continuous therapies in PD include the transdermal Rotigotine (RTG) patch, infusion therapies with Apomorphine and Intrajejunal Levodopa (IJLI) and the Rivastigmine patch. Here we aim to provide a concise review of these current therapies and discuss ongoing and future developments of continuous non-oral pharmacological dopaminergic therapies in PD.

Apomorphine in the treatment of Parkinson's disease: a review

Optimizing idiopathic Parkinson's disease treatment is a challenging, multifaceted and continuous process with direct impact on patients' quality of life. The basic tenet of this task entails tailored therapy, allowing for optimal motor function with the fewest adverse effects. Apomorphine, a dopamine agonist used as rescue therapy for patients with motor fluctuations, with potential positive effects on nonmotor symptoms, is the only antiparkinsonian agent whose capacity to control motor symptoms is comparable to that of levodopa. Subcutaneous administration, either as an intermittent injection or as continuous infusion, appears to be the most effective and tolerable route. This review summarizes the historical background, structure, mechanism of action, indications, contraindications and side effects, compares apomorphine infusion therapy with other treatments, such as oral therapy, deep brain stimulation and continuous enteral infusion of levodopa/carbidopa gel, and gives practical instructions on how to initiate treatment.

The current status of pharmacotherapy for the treatment of Parkinson's disease: transition from single-target to multitarget therapy

Parkinson's disease (PD) is a neurodegenerative disorder characterized by degeneration of dopaminergic neurons. Motor features such as tremor, rigidity, bradykinesia and postural instability are common traits of PD. Current treatment options provide symptomatic relief to the condition but are unable to reverse disease progression. The conventional single-target therapeutic approach might not always induce the desired effect owing to the multifactorial nature of PD. Hence, multitarget strategies have been proposed to simultaneously target multiple proteins involved in the development of PD. Herein, we provide an overview of the pathogenesis of PD and the current pharmacotherapies. Furthermore, rationales and examples of multitarget approaches that have been tested in preclinical trials for the treatment of PD are also discussed.

Continuous subcutaneous apomorphine in advanced Parkinson's disease patients treated with deep brain stimulation

INTRODUCTION

Deep brain stimulation (DBS) is an effective therapy for patients with advanced Parkinson's disease (PD). However, sometimes, it is not sufficient to adequately control motor symptoms. We describe our experience with continuous subcutaneous apomorphine infusion (APO) in patients with DBS.

METHODS

We undertook a retrospective analysis of all patients treated with DBS and APO at our centre over 12 years. Subjects were allocated to four groups: (1) APO temporarily before DBS, (2) APO after DBS complications before a new DBS, (3) APO after definitive DBS removal, and (4) APO in patients with DBS and declining response. Motor state and other parameters were analysed and compared for the different treatments.

RESULTS

Data for 71 patients were evaluated. Group 1: (n = 18) patients improved their motor function significantly with both APO and DBS (off-hours before APO 5.4 ± 1.4; after APO 1.4 ± 1.2, p > 0.001; after DBS 0.7 ± 0.8, p < 0.001). Group 2: (n = 11) patients were found to have mild but significant worsening of motor state between the first DBS treatment (off-hours 0.7 ± 1.0) and APO (2.2 ± 1.5, p = 0.02), and improvement between APO and the second DBS treatment (off-hours 0.6 ± 0.8, p = 0.03). Group 3: (n = 12) patients had mild but significant worsening of motor function between DBS (off-hours 1.1 ± 1.0) and APO (2.0 ± 0.9, p = 0.03). Group 4: (n = 13) significant improvement in motor function was observed between DBS alone (off-hours 3.9 ± 2.6) and DBS combined with APO (2.2 ± 1.3, p = 0.03).

CONCLUSION

In advanced PD, DBS may be not sufficient or may fail to control motor symptoms adequately. In these cases, APO, whether alone or in combination with DBS, is a good choice to improve the disease control.

Parkinson's disease: symptoms, treatment options and nursing care

Idiopathic Parkinson's disease (IPD) is a progressive neurodegenerative condition that causes various motor and non-motor symptoms and will often have life-changing effects for those with the condition, as well as for their family and carers. Nurses can make a significant difference to the lives of those affected by Parkinson's disease, whether in the acute setting, community setting or in care homes. This article explores the causes and progressive clinical pathway of IPD using an evidence-based approach. It emphasises the valuable role of the multidisciplinary team and of the nurse, in particular, in monitoring and improving the quality of life of those with the condition and their family and carers.

Therapeutic strategies for Parkinson disease: beyond dopaminergic drugs

Existing therapeutic strategies for managing Parkinson disease (PD), which focus on addressing the loss of dopamine and dopaminergic function linked with degeneration of dopaminergic neurons, are limited by side effects and lack of long-term efficacy. In recent decades, research into PD pathophysiology and pharmacology has focused on understanding and tackling the neurodegenerative processes and symptomology of PD. In this Review, we discuss the challenges associated with the development of novel therapies for PD, highlighting emerging agents that aim to target cell death, as well as new targets offering a symptomatic approach to managing features and progression of the disease.

ND0701, A Novel Formulation of Apomorphine for Subcutaneous Infusion, in Comparison to a Commercial Apomorphine Formulation: 28-Day Pharmacokinetic Study in Minipigs and a Phase I Study in Healthy Volunteers to Assess the Safety, Tolerability, Pharmacokinetics and Relative Bioavailability

BACKGROUND

Subcutaneous apomorphine is used for the treatment of Parkinson's disease (PD); however, infusion site reactions are a common adverse event (AE), which can lead to treatment discontinuation. Apomorphine formulations that are more tolerable and convenient for use are needed.

OBJECTIVE

Our aim was to compare the toxicity and bioavailability of ND0701, a new concentrated formulation of apomorphine free base, with one of the commercially available apomorphine HCl formulations (APO-go^®, Britannia Pharmaceuticals Ltd).

METHODS

(1) Preclinical study: 16 minipigs were randomly assigned to placebo, APO-go^®, and ND0701 groups, and treated for 28 days. Pharmacokinetic, clinical, and pathological assessments were performed. (2) Phase I study: 18 healthy volunteers participated in an open-label, two-sequence, randomized, three single-dose, partial crossover study to compare the pharmacokinetics, safety, and tolerability of ND0701 with APO-go^® (1%).

RESULTS

(1) Preclinical study: No systemic toxicity was observed in apomorphine-treated minipigs, but local skin reactions were observed at the infusion sites. These effects were less frequent and less severe and recovery was more rapid for ND0701 compared with APO-go^®. (2) Phase I study: Both formulations were safe and well tolerated under the conditions of the study and no severe or serious treatment-emergent AEs were reported. Infusion site nodules were reported more frequently, with higher severity, and recovered slower at APO-go^®-treated sites compared with ND0701-treated sites. Bioavailability of apomorphine was comparable between the two formulations.

CONCLUSION

Based on these pilot studies, ND0701 appears to be superior to APO-go^® in terms of tolerability and safety, while maintaining comparable bioavailability with APO-go^®, and shows promise as a future treatment for PD.

Rotigotine transdermal patch and sleep in Parkinson's disease: where are we now?

A wide range of sleep dysfunction complicates Parkinson’s disease during its course from prodromal to palliative stage. It is now increasingly acknowledged that sleep disturbances are thus integral to the disease and pose a significant burden impacting on quality of life of patients. Sleep fragmentation, restless legs syndrome, nocturia, and nocturnal pain are regarded as one of the main components of night-time sleep dysfunction with possible secondary impact on cognition and well-being. The role of dopaminergic therapies, particularly using a continuous drug delivery strategy in managing some of these sleep issues, have been reported but the overall concept remains unclear. This review provides an overview of several aspects of night-time sleep dysfunction in Parkinson’s disease and describes all available published open-label and blinded studies that investigated the use of rotigotine transdermal patch targeting sleep. Blinded studies have suggested beneficial effects of rotigotine transdermal patch on maintenance insomnia and restless legs syndrome in Parkinson’s disease patients. Open-label studies support these observations and also suggest beneficial effects on nocturia and nocturnal pain.

Nonmotor Subtyping in Parkinson's Disease

Nonmotor symptoms are integral to Parkinson's disease. Several subtypes dominated by specific nonmotor symptoms have emerged. In this chapter, the rationale behind nonmotor subtyping and currently proposed nonmotor subgroups within Parkinson's disease based on data-driven cluster analysis and clinical observations will be summarized. Furthermore, the concept of seven clinical nonmotor subtypes will be discussed in detail including the clinical presentation, potential biomarkers, and the clinical relevance. In future, nonmotor subtypes will possibly play a major role within the aim to achieve personalized medicine.