Rationale and patient selection for interventional therapies in Parkinson’s disease

Levodopa-carbidopa intestinal gel infusion (LCIG) in Parkinson disease with genetic mutations

BACKGROUND

Levodopa-carbidopa intestinal gel infusion (LCIG) is a therapeutic option for advanced Parkinson disease (PD) patients with troublesome motor complications, unresponsive to conventional oral treatment. There is some evidence to suggest that the genetic background may influence the clinical presentation and rate of progression of PD. Whether the genetic background influences the outcome of device-assisted therapies is currently debated. Some studies have investigated the effectiveness of deep brain stimulation (DBS) in PD patients with different genetic background, while evidence is lacking regarding LCIG.

METHODS

A cohort of LCIG patients underwent genetic testing. The motor and neuropsychological outcomes of LCIG were retrospectively analyzed.

RESULTS

Fifty-six patients were analyzed, nine of them (15%) had at least one mutation/variant in a PD-associated gene: five GBA1, two SNCA, one LRRK2, one PRKN; 13 (23%) carried the BDNF Val66Met polymorphism. The mean duration of follow-up was 4.9 ± 2.6 years. There were no significant differences in motor or neuropsychological outcomes between patients with and without these gene mutations/variants. No cognitive worsening was observed at follow-up among GBA-PD patients, and they responded well to LCIG in terms of motor symptoms.

CONCLUSIONS

Overall, we observed a significant benefit in terms of motor complications in our cohort, including patients carrying genetic mutations/variants. Due to the small sample and limited number of patients carrying genetic mutations/variants, no definitive conclusions can be drawn yet on the genotype impact on LCIG outcome. A careful selection of patients, regardless of the genetic background, is pivotal for an optimal outcome of LCIG.

Tools and criteria to select patients with advanced Parkinson's disease for device-aided therapies: a narrative review

This article provides an overview of the various screening and selection tools which have been developed over the past 25 years to identify patients with Parkinson's disease (PD) possibly eligible for device-aided therapies (DATs). For the available screening tools, we describe the target therapies (subtypes of DAT), development methods, validation data, and their use in clinical practice. In addition, the historical background and potential utility of these screening tools are discussed. The challenges in developing and validating these tools are also addressed, taking into account the differences in population, the local health care organization, and resource availability.

A Review on Response to Device-Aided Therapies Used in Monogenic Parkinsonism and GBA Variants Carriers: A Need for Guidelines and Comparative Studies

Parkinson's disease (PD) is in some cases predisposed-or-caused by genetic variants, contributing to the expression of different phenotypes. Regardless of etiology, as the disease progresses, motor fluctuations and/or levodopa-induced dyskinesias limit the benefit of pharmacotherapy. Device-aided therapies are good alternatives in advanced disease, including deep brain stimulation (DBS), levodopa-carbidopa intestinal gel, and continuous subcutaneous infusion of apomorphine. Candidate selection and timing are critical for the success of such therapies. Genetic screening in DBS cohorts has shown a higher proportion of mutation carriers than in general cohorts, suggesting that genetic factors may influence candidacy for advanced therapies. The response of monogenic PD to device therapies is not well established, and the contribution of genetic information to decision-making is still a matter of debate. The limited evidence regarding gene-dependent response to device-aided therapies is reviewed here. An accurate understanding of the adequacy and responses of different mutation carriers to device-aided therapies requires the development of specific studies with long-term monitoring.

Neurologists' Attitudes Toward Use and Timing of Deep Brain Stimulation

OBJECTIVE

We sought to explore current perspectives and attitudes of general neurologists and movement disorder specialists toward deep brain stimulation (DBS) for Parkinson disease (PD), focusing on perspectives on its earlier use in the clinical course of the disease.

METHODS

We designed a 30-question online survey comprised of Likert-type, multiple choice, and rank-order questions, which was distributed to 932 neurologist members of the American Academy of Neurology. We analyzed clinicians' sociodemographic information, treatment patterns used for patients with PD, reasons for and against patient referral for DBS, and general attitudes toward DBS. Data were analyzed using descriptive and inferential statistics.

RESULTS

We received 164/930 completed surveys (completion rate of 18%). Overall, most respondents agreed that DBS was more useful after the appearance of motor complications and that DBS utilization offered better management of PD than medication alone. However, respondents were divided on issues like minimum duration of disease needed to consider DBS as a treatment option and timing of DBS referral relative to disease progression. Specifically, differences between movement disorder specialists and general neurologists were seen in medication management of symptoms and dyskinesia.

CONCLUSIONS

There remains a lack of consensus on several aspects of DBS, including medical management before offering DBS and the appropriate timing of its consideration for patients. Given the effect of such lack of consensus on patients' outcomes and recent evidence on positive DBS results, it is essential to update DBS professional guidelines with a focus on medical management and the timely use of DBS.

Bringing Advanced Therapies for Parkinson's Disease to the Clinic: An Analysis of Ethical Issues

Advanced therapies for Parkinson’s disease (PD) constitute a broad range of treatments, each presenting specific ethical challenges. Some of these therapies are established and in clinical use, like device-aided therapies, and others, based on advanced therapeutic medicinal products (ATMPs), are still in early stage of clinical trials. This paper focuses on some common ethical issues arising in these two categories of advanced therapies, especially challenges arising when advanced therapies are proposed to PD patients in the form of advanced care, under a clinical trial, or, in case of ATMPs, under the “hospital exemption” rule. The ethical issues covered here relate mainly to ensuring informed consent in these different contexts, to the stakeholder role of patient’s non-professional caretakers, such as family, and to patient safety in treatments under “hospital exemption”. To illustrate the points discussed in connection with “hospital exemption” rule, the example of the EU has been chosen. This paper does not claim completeness of ethical issues raised by bringing advanced therapies for PD to the clinic, but rather presents examples of ethical challenges in this context.

Should we start integrating genetic data in decision-making on device-aided therapies in Parkinson disease? A point of view

Parkinson disease (PD) is a complex heterogeneous neurodegenerative disorder. Association studies have revealed numerous genetic risk loci and variants, and about 5-10% suffer from a monogenic form. Because the presentation and course of PD is unique to each patient, personalized symptomatic treatment should ideally be offered to treat the most disabling motor and non-motor symptoms. Indeed, clinical milestones and treatment complications that appear during disease progression are influenced by the genetic imprint. With recent advances in PD, more patients live longer to become eligible for device-aided therapies, such as apomorphine continuous subcutaneous infusion, levodopa duodenal gel infusion, and deep brain stimulation surgery, each with its own inclusion and exclusion criteria, advantages and disadvantages. Because genetic variants influence the expression of particular clinical profiles, factors for better or worse outcomes for device-aided therapies may then be proactively identified. For example, mutations in PRKN, LRRK2 and GBA express phenotypes that favor suitability for different device therapies, although with marked differences in the therapeutic window; whereas multiplications of SNCA express phenotypes that make them less desirable for device therapies.

Parkinson's Disease in the Middle East, North Africa, and South Asia: Consensus from the International Parkinson and Movement Disorder Society Task Force for the Middle East

BACKGROUND

Understanding the regional needs and available healthcare resources to treat Parkinson's disease (PD) is essential to plan appropriate future priorities. The International Parkinson and Movement Disorder Society (MDS) Task Force for the Middle East was established to raise awareness and promote education across the region on PD and other movement disorders. Broadly, the task force encompasses the countries of the Middle East but has included North Africa and South Asia as well (MENASA).

OBJECTIVE

To create a list of needs and priorities in the advancement of PD in MENASA countries based on consensuses generated by the MDS task force for the Middle East.

METHODS

A Strengths Weaknesses-Opportunities-Threats (SWOT) analysis was conducted by the task force members to generate consensus about PD care this region.

RESULTS

Eight overarching principles emerged for the consensus statement on current needs: more movement disorders specialists, multidisciplinary care, accurate epidemiologic data, educational programs, availability of drugs, and availability of more advanced therapy, enhanced health care resources and infrastructure, and greater levels of awareness within the general population and among health care professionals.

CONCLUSION

This pilot study sheds light on unmet needs for providing care to people with PD in the MENASA region. These data offer directions on priorities to increase awareness of PD, to develop better infrastructure for research and management of PD, to foster healthcare policy discussions for PD and to provide educational opportunities within these countries.

Perspectives on the Earlier Use of Deep Brain Stimulation for Parkinson Disease from a Qualitative Study of U.S. Clinicians

BACKGROUND

In November 2015, the U.S. Food and Drug Administration (FDA) approved the use of deep brain stimulation (DBS) therapy in people with Parkinson's disease (PD) "of at least four years duration and with a recent onset of motor complications, or motor complications of longer-standing duration that are not adequately controlled with medication." Although the full implications of this more recent approval are yet to be determined, to date, there are no strict criteria defining appropriate earlier use of DBS. As such, confusion remains regarding the actual meaning of early DBS initiation. To better inform responsive policy, we sought the perspectives of movement disorder neurologists and neurosurgeons regarding the earlier use of DBS. Insights from these clinicians are key to developing appropriate clinical guidelines and determining how early is too early. The objective of this study is to explore attitudes among clinicians toward the earlier use of DBS for PD.

METHODS

Twelve Michigan-based clinicians were interviewed both about DBS referral/use processes and their perspectives regarding the earlier use of DBS in PD. We used a structured interview with closed- and open-ended questions. All interviews were transcribed verbatim and analyzed using a mixed-method approach.

RESULTS

We found that most clinicians considered earlier use not solely to be time dependent but instead determined by patient symptoms. Only 16.8% were aware of the FDA's recent indication of early use of DBS, with 25% of our respondents being unsure as to whether it should be seen as an early treatment modality. On average, neurologists suggested DBS as the next treatment option, after medications have been exhausted, typically 6 years after diagnosis.

CONCLUSIONS

There remain wide variations in terms of clinicians' parameters for referrals and timing of DBS. Larger studies are needed to support or refute our findings.