Clinical insights into use of apomorphine in Parkinson's disease: tools for clinicians

Feasibility and benefits of home initiation of subcutaneous apomorphine infusion for patients with Parkinson's disease: the APOKADO study

Continuous subcutaneous apomorphine infusion (CSAI) is used to treat patients with Parkinson's disease (PD) who are experiencing motor fluctuations. However, the need to initiate this treatment during a hospital stay may restrict patients' access to it. To assess the feasibility and benefits of initiating CSAI in the patient's own home. A French prospective multicenter longitudinal observational study (APOKADO) among patients with PD who required subcutaneous apomorphine, comparing in-hospital versus home initiation. Clinical status was assessed according to the Hoehn and Yahr score), the Unified Parkinson's Disease Rating Scale Part III, and the Montreal Cognitive Assessment. We assessed patients' quality of life with the 8-item Parkinson's Disease Questionnaire, rated the improvement in their clinical status on the 7-point Clinical Global Impression-Improvement scale, recorded adverse events, and ran a cost-benefit analysis. 145 patients with motor fluctuations were included in 29 centers (office and hospital). Of these, 106 (74%) were initiated onto CSAI at home, and 38 (26%) in hospital. At inclusion, the two groups were comparable for all demographic and PD characteristics. After 6 months, quality of life, adverse events and early dropout rates were similarly rare-across the two groups. Patients in the home group improved more quickly their quality of life and became more autonomous in managing the device than those in the hospital group, and their care costed less. This study shows that home (versus in-hospital) initiation of CSAI is feasible, improves patients' quality of life more quickly, with the same level of tolerance. It is also less expensive. This finding should make it easier for patients to access this treatment in the future.

Liposomes: Novel Drug Delivery Approach for Targeting Parkinson's Disease

Parkinson's disease is one of the most severe progressive neurodegenerative disorders, having a mortifying effect on the health of millions of people around the globe. The neural cells producing dopamine in the substantia nigra of the brain die out. This leads to symptoms like hypokinesia, rigidity, bradykinesia, and rest tremor. Parkinsonism cannot be cured, but the symptoms can be reduced with the intervention of medicinal drugs, surgical treatments, and physical therapies. Delivering drugs to the brain for treating Parkinson's disease is very challenging. The blood-brain barrier acts as a highly selective semi-permeable barrier, which refrains the drug from reaching the brain. Conventional drug delivery systems used for Parkinson's disease do not readily cross the blood barrier and further lead to several side-effects. Recent advancements in drug delivery technologies have facilitated drug delivery to the brain without flooding the bloodstream and by directly targeting the neurons. In the era of Nanotherapeutics, liposomes are an efficient drug delivery option for brain targeting. Liposomes facilitate the passage of drugs across the blood-brain barrier, enhances the efficacy of the drugs, and minimize the side effects related to it. The review aims at providing a broad updated view of the liposomes, which can be used for targeting Parkinson's disease.

An evaluation of subcutaneous apomorphine for the treatment of Parkinson's disease

INTRODUCTION

Heterogeneity of symptoms and individual variability of progression characterizes Parkinson's disease. Unmet therapeutic needs include a cure, disease modification, and improvement of available marketed dopamine-substituting compounds. Personalized treatment, tailored to the patients' needs and symptoms, aims to ameliorate impaired motor behavior and non-motor features. Injection or infusion of apomorphine is a therapeutic option for more advanced patients with severe levodopa associated motor complications.

AREAS COVERED

This narrative review summarizes the subcutaneous administration, efficacy, and side effects of the non-ergot derivative dopamine agonist apomorphine following a non-systematic literature research.

EXPERT OPINION

Subcutaneous apomorphine hydrochloride application rapidly terminates intervals with severe motor impairment with bolus injections. Oscillation of motor behavior well responds to continuous apomorphine infusions. Long-term application of the commercially available apomorphine hydrochloride solution sooner or later affects skin and oral mucosa. Onset of skin nodules associated with subcutaneous tissue inflammation probably results from the antioxidant preservative sodium metabisulfite in the apomorphine solution. Addition of another better tolerated and safer antioxidant instead of sodium metabisulphite or use of an already available concentrated apomorphine-free base formulation will enhance its future use, its tolerability, safety, and acceptance of subcutaneous and sublingual application.

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.

Identification of C10 nitrogen-containing aporphines with dopamine D1 versus D5 receptor selectivity

New aporphines containing C10 nitrogen substituents (viz. nitro, aniline or amide moieties), were synthesized and evaluated for affinity at human serotonin 5-HT_1A and 5-HT_2A receptors and at human dopamine D₁, D₂ and D₅ receptors. Two series of analogs were investigated: series A which contain a sole C10 nitrogen substituent on the tetracyclic aporphine core and series B which are 1,2,10-trisubstituted aporphines. Remarkably, compounds from both series lacked affinity for the D₅ receptor, thus attaining D₁ versus D₅ selectivity. Compound 20c was the most potent D₁ ligand identified. Docking studies at D₁ and D₅ receptors indicate that the binding mode of 20c at the D₁ receptor allows for stronger hydrophobic contacts, (primarily with Phe residues) as compared to the D₅ receptor, accounting for its D₁ versus D₅ selectivity. Considering the lack of affinity for the D₅ receptor (and low affinity at other receptors tested), compound 20c represents an interesting starting point for further structural diversification of aporphines as sub-type selective D₁ receptor tools.

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.

Adjunctive Therapies in Parkinson's Disease: How to Choose the Best Treatment Strategy Approach

End-of-dose motor fluctuations are regarded as one of the core troublesome symptoms by patients with Parkinson's disease (PD). Treatment of levodopa (L-dopa)-induced motor fluctuations is still an unmet medical need. L-dopa is the gold standard in the treatment of motor PD symptoms; notwithstanding, a wide range of adjunct therapies are currently available for the treatment of end-of-dose motor fluctuations. Additionally, device-aided therapies, such as deep brain stimulation, L-dopa-carbidopa intestinal gel infusion, and on-demand injection or continuous apomorphine infusion, may be considered when oral treatments are not sufficient to control motor fluctuations. In spite of the several evidence-based reviews and guidelines available, there is no agreement on which add-on therapy should be started first or its optimal timing. Equally challenging is the choice and timing between device-aided therapies. Herein, we propose a general overview of oral and device-aided treatments for PD patients with end-of-dose motor fluctuations, offering two possible algorithms that can guide clinicians during the therapeutic decision process.

The Many Faces of Apomorphine: Lessons from the Past and Challenges for the Future

Apomorphine is now recognized as the oldest antiparkinsonian drug on the market. Though still underused, it is increasingly prescribed in Europe for patients with advanced Parkinson's disease (PD) with motor fluctuations. However, its history is far from being limited to movement disorders. This paper traces the history of apomorphine, from its earliest empirical use, to its synthesis, pharmacological development, and numerous indications in human and veterinary medicine, in light of its most recent uses and newest challenges. From shamanic rituals in ancient Egypt and Mesoamerica, to the treatment of erectile dysfunction, from being discarded as a pharmacological tool to becoming an essential antiparkinsonian drug, the path of apomorphine in the therapeutic armamentarium has been tortuous and punctuated by setbacks and groundbreaking discoveries. Throughout history, three main clinical indications stood out: emetic (gastric emptying, respiratory disorders, aversive conditioning), sedative (mental disorders, clinical anesthesia, alcoholism), and antiparkinsonian (fluctuations). New indications may arise in the future, both in PD (palliative care, nonmotor symptoms, withdrawal of oral dopaminergic medication), and outside PD, with promising work in neuroprotection or addiction.

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.

Continuous subcutaneous apomorphine infusion in Parkinson's disease patients with cognitive dysfunction: A retrospective long-term follow-up study

INTRODUCTION

Continuous apomorphine infusion (CAI) is an advanced therapy in fluctuating Parkinson's disease (PD). The use of CAI is controversial in PD patients with cognitive dysfunction including visual hallucinations (VHs), and orthostatic hypotension (OH). This study was set-up to analyze the effectiveness and safety of CAI in elderly PD patients with cognitive dysfunction.

METHODS

This new-user cohort study identified fluctuating PD patients who started CAI treatment at the rehabilitation unit of Parkinson Expertise Center (RU-PEC) Groningen, from November 2004 until 2016. Efficacy and safety data included motor function, cognitive status, OH and VHs, and was analyzed retrospectively. Pre-existent non-motor symptoms were treated optimally before starting CAI.

RESULTS

Forty-five fluctuating PD patients (age: 70.9 ± 8.1 yrs, disease duration: 10.8 ± 4.8 yrs) were identified, with pre-existing cognitive dysfunction, VHs (71%), and OH (26%). During the stay at RU-PEC (median 52 days) apomorphine was successfully titrated without worsening of pre-existing VHs and OH. The mean daily apomorphine dose was 66 ± 28 mg, accompanied by a reduction of levodopa-equivalent daily dose (LEDD) with 17%. The duration of ON-time and OFF-time significantly improved with +2.36 h (25%) and -1.66 h (-45%), respectively, while dyskinesia duration did not change. During long-term follow-up (median of 26 months) VHs and OH worsened in 9 and 4 patients, which necessitated discontinuation in 4 cases.

CONCLUSION

This study demonstrates that CAI is also an effective treatment in advanced PD patients with concomitant cognitive dysfunction including VHs and OH, provided that these comorbidities are treated adequately as well.

Magnetic Resonance Imaging as a Noninvasive Method for Longitudinal Monitoring of Infusion Site Reactions Following Administration of a Novel Apomorphine Formulation

Infusion site reactions are common following subcutaneous infusion of drugs. Such reactions can lead to discontinuation of the treatment. Therefore, assessment of such reactions is essential during preclinical safety studies, and magnetic resonance imaging (MRI) can assist in evaluation. Here, in vivo and ex vivo MRI evaluations were used in addition to classical histopathology to assess the infusion site reaction to ND0701, a novel formulation of apomorphine base developed for the treatment of Parkinson’s disease, in comparison to the commercial apomorphine hydrochloride (HCl) formulation. Both formulations, each at two concentrations, were continuously administered subcutaneously for 20 hr to each of 3 male and 3 female domestic pigs. Based on MRI evaluations, there was a gradual decrease in the volume of the subcutaneous lesions over 4 weeks, with smaller lesions and quicker resolution with ND0701 at concentrations 2.5- to 5-fold higher when compared to the commercial apomorphine HCl formulation. Histopathological evaluation of ND0701 revealed only minimal inflammation at the sites of infusion, whereas the commercial apomorphine HCl caused persistent inflammatory reactions and necrosis. This study provides support to the use of MRI in preclinical testing of subcutaneous drugs when evaluating local site reactions.

Understanding the role of the Parkinson's disease nurse specialist in the delivery of apomorphine therpy

Optimal care of Parkinson's disease (PD) patients should involve a multidisciplinary team (MDT) of which a PD nurse specialist (PDNS) is a key member. The role of a PDNS is particularly prominent in the care of advanced PD patients suitable for apomorphine because, in addition to nursing skills, apomorphine treatment requires liaison, training, interaction and coordination with patients, caregivers and other members of the MDT as well as the interface with primary care physicians. The therapeutic success of apomorphine therapy depends not only upon the pharmacologic drug response, but also on how well the patient understands his/her disease and how to handle the therapy. In this respect, a PDNS is a vital member of the MDT who provides education and training, support, and is available for consultation when problems arise. In this article, we review the literature on the contribution of PDNSs in both continuous subcutaneous apomorphine infusion and intermittent subcutaneous apomorphine injection and highlight the various beneficial aspects of PDNS care, supported by scientific evidence when available. Despite a low level of published evidence, there is strong clinical evidence that the impact of PDNSs on the management of apomorphine therapy is vital and indispensable for the success of this treatment.

Apomorphine pump in advanced Parkinson's disease: Effects on motor and nonmotor symptoms with brain metabolism correlations

INTRODUCTION

Patients with advanced Parkinson's disease (PD) and contraindications for subthalamic nucleus deep brain stimulation (DBS) could particularly benefit from subcutaneous infusion therapy with apomorphine. This original study was designed to evaluate the general efficacy of add-on apomorphine in motor and nonmotor symptoms in advanced PD, while characterizing the changes induced in brain glucose metabolism. The aim was to look at the underlying anatomical-functional pathways.

METHODS

12 patients with advanced PD were assessed before and after 6months of add-on apomorphine, using resting-state ¹⁸F-fluorodeoxyglucose positron emission tomography and exhaustive clinical assessments.

RESULTS

After 6months of therapy, oral treatment was significantly reduced. Both motor and nonmotor scores improved, with a beneficial effect on executive functions, quality of life and apathy. Significant metabolic changes were observed, with overall increases in the right fusiform gyrus and hippocampus, alongside a decrease in the left middle frontal gyrus. Consistent correlations between significant changes in clinical scores and metabolism were established.

CONCLUSION

Well tolerated, add-on apomorphine appears to be an interesting option for patients with fluctuations and contra-indications for DBS. Changes in brain metabolism, with beneficial effects on motor and nonmotor symptoms were observed after 6months. These preliminary results have to be confirmed by further studies.

Practical management of adverse events related to apomorphine therapy

The potential for adverse events is often cited as a barrier to the use of subcutaneous apomorphine therapy (intermittent injections and continuous infusion) in the management of Parkinson's disease. However, with proactive management most adverse effects are manageable if reported and tackled early enough. As such, proper clinician and patient awareness of the potential adverse effects is important to minimize their impact on the overall clinical utility of this efficacious antiparkinsonian agent. In this paper, we review the key local and systemic adverse effects reported during apomorphine titration, initiation and long-term treatment, and discuss practical management strategies.

Nanomedicine to Overcome Current Parkinson's Treatment Liabilities: A Systematic Review

Nanoparticles might be produced and manipulated to present a large spectrum of properties. The physicochemical features of the engineered nanomaterials confer to them different features, including the ability to cross the blood-brain barrier. The main objective of this review is to present the state-of-art research in nano manipulation concerning Parkinson's disease (PD). In the past few years, the association of drugs with nanoparticles solidly improved treatment outcomes. We systematically reviewed 28 studies, describing their potential contributions regarding the role of nanomedicine to increase the efficacy of known pharmacological strategies for PD treatment. Data from animal models resulted in the (i) improvement of pharmacological properties, (ii) more stable drug concentrations, (iii) longer half-live and (iv) attenuation of pharmacological adverse effects. As this approach is recent, with many of the described works being published less than 5 years ago, the expectancy is that this knowledge gives support to an improvement in the current clinical methods to the management of PD and other neurodegenerative diseases.

Novel protein-inhibitor interactions in site 3 of Ca(2+)-bound S100B as discovered by X-ray crystallography

Structure-based drug discovery is under way to identify and develop small-molecule S100B inhibitors (SBiXs). Such inhibitors have therapeutic potential for treating malignant melanoma, since high levels of S100B downregulate wild-type p53 tumor suppressor function in this cancer. Computational and X-ray crystallographic studies of two S100B-SBiX complexes are described, and both compounds (apomorphine hydrochloride and ethidium bromide) occupy an area of the S100B hydrophobic cleft which is termed site 3. These data also reveal novel protein-inhibitor interactions which can be used in future drug-design studies to improve SBiX affinity and specificity. Of particular interest, apomorphine hydrochloride showed S100B-dependent killing in melanoma cell assays, although the efficacy exceeds its affinity for S100B and implicates possible off-target contributions. Because there are no structural data available for compounds occupying site 3 alone, these studies contribute towards the structure-based approach to targeting S100B by including interactions with residues in site 3 of S100B.