Outpatient titration of carbidopa/levodopa enteral suspension (Duopa)

Emerging Pharmacotherapies for Motor Symptoms in Parkinson's Disease

Parkinson's disease (PD) is the second commonest neurodegenerative disorder in the older adult and is characterized by progressive disabling motor symptoms of bradykinesia, tremor, rigidity, postural instability and also non motor symptoms that affect quality of life. The pharmacotherapy of PD consists of oral, transdermal, and subcutaneous medications, as well as invasive advanced therapies at later stages of the disease. PD medications are often started as monotherapy but with the progression of the illness often there is a need to add more medications and frequently comprises of a challenging polypharmacotherapy. Adverse effects of pharmacotherapy often add to the problems of adequate treatment. Patients and physicians have to prioritize treatment goals on the most disabling symptoms and the safest and most effective treatments. Almost every year newer medications and modes of delivery continue to be researched and added to the therapeutic armamentarium. This review article outlines existing and emerging pharmacotherapies for motor symptoms in PD.

The Long-Term Impact of Levodopa/Carbidopa Intestinal Gel on 'Off'-time in Patients with Advanced Parkinson's Disease: A Systematic Review

INTRODUCTION

Levodopa/carbidopa intestinal gel (LCIG; carbidopa/levodopa enteral suspension) has been widely used and studied for the treatment of motor fluctuations in levodopa-responsive patients with advanced Parkinson's disease (PD) when other treatments have not given satisfactory results. Reduction in 'off'-time is a common primary endpoint in studies of LCIG, and it is important to assess the durability of this response. This systematic literature review was conducted to qualitatively summarise the data on the long-term effects of LCIG therapy on 'off'-time.

METHODS

Studies were identified by searching PubMed, EMBASE and Ovid on 30 September 2019. Studies were included if they reported on patients with PD, had a sample size of ≥ 10, LCIG was an active intervention and 'off'-time was reported for ≥ 12 months after initiation of LCIG treatment. Randomised clinical trials, retrospective and prospective observational studies, and other interventional studies were included for selection. Data were collected on: 'off'-time (at pre-specified time periods and the end of follow-up), study characteristics, Unified Parkinson's Disease Rating Scale (UPDRS) II, III and IV total scores, dyskinesia duration, quality of life scores, non-motor symptoms and safety outcomes.

RESULTS

Twenty-seven studies were included in this review. The improvement in 'off'-time observed shortly after initiating LCIG was maintained and was statistically significant at the end of follow-up in 24 of 27 studies. 'Off'-time was reduced from baseline to end of follow-up by 38-84% and was accompanied by a clinically meaningful improvement in quality of life. Stratified analysis of 'off'-time demonstrated mean relative reductions of 47-82% at 3-6 months and up to 83% reduction at 3-5 years of follow-up. Most studies reported significant improvements in activities of daily living and motor complications. Most frequent adverse events were related to the procedure or the device.

CONCLUSION

In one of the largest qualitative syntheses of published LCIG studies, LCIG treatment was observed to provide a durable effect in reducing 'off'-time.

INFOGRAPHIC

Video Abstract.

Treating Parkinson's disease by astrocyte reprogramming: Progress and challenges

Parkinson's disease (PD), the second most prevalent neurodegenerative disorder, is typified by both motor and nonmotor symptoms. The current medications provide symptomatic relief but do not stimulate the production of new dopaminergic neurons in the substantia nigra. Astrocyte reprogramming has recently received much attention as an avenue for increasing functional dopaminergic neurons in the mouse PD brain. By targeting a microRNA (miRNA) loop, astrocytes in the mouse brain could be reprogrammed into functional dopaminergic neurons. Such in vivo astrocyte reprogramming in the mouse model of PD has successfully added new dopaminergic neurons to the substantia nigra and increased dopamine levels associated with axonal projections into the striatum. This review deliberates the astrocyte reprogramming methods using specific transcription factors and mRNAs and the progress in generating dopaminergic neurons in vivo. In addition, the translational potential, challenges, and potential risks of astrocyte reprogramming for an enduring alleviation of parkinsonian symptoms are conferred.

Current Practices for Outpatient Initiation of Levodopa-Carbidopa Intestinal Gel for Management of Advanced Parkinson's Disease in the United States

In 2015, the US Food and Drug Administration approved levodopa-carbidopa intestinal gel (LCIG; also known as carbidopa-levodopa enteral suspension in the US) for the treatment of motor fluctuations in patients with advanced Parkinson's disease. LCIG provides a continuous infusion of levodopa and carbidopa by means of a portable pump and percutaneous endoscopic gastrojejunostomy tube. The delivery system has a two-fold pharmacokinetic advantage over orally administered carbidopa/levodopa. First, levodopa is delivered in a continuous rather than intermittent, pulsatile fashion. Second, delivery to levodopa's site of absorption in the jejunum bypasses the stomach, thereby avoiding issues with erratic gastric emptying. In blinded prospective clinical trials and observational studies, LCIG has been shown to significantly decrease "off" time, increase "on" time without troublesome dyskinesia, and reduce dyskinesia. Consistent with procedures in previous studies, LCIG initiation and titration in the pivotal US clinical trial were performed in the inpatient setting and followed a standardized protocol. In clinical practice, however, initiation and titration of LCIG have a great degree of flexibility and, in the US, almost always take place in the outpatient setting. Nonetheless, there remains a significant amount of clinician uncertainty regarding titration in outpatient clinical practice. This review aims to shed light on and provide guidance as to the current methods of titration in the outpatient setting, as informed by the medical literature and the authors' experiences. FUNDING: AbbVie, Inc. Plain language summary available for this article.

Using tube feeding and levodopa-carbidopa intestinal gel application in advanced Parkinson's disease

The inability to achieve adequate nutrition and weight loss are serious problems for patients with advanced Parkinson's disease (PD). To ensure the optimal intake of nutrition and fluids and to administer levodopa-carbidopa intestinal gel (LCIG) (which patients need to increase or maintain their mobility as long as possible), different artificial feeding tubes can be used. Although percutaneous endoscopic gastrostomy (PEG) tubes are frequently used in medical practice, there is little research that addresses key questions, including if and when to administer artificial fluids, nutrition and/or LCIG via tubes. Weight gain through tube feeding is only possible for some patients; nurses should keep in mind that tube insertion and feeding may lead to frequent adverse events. Administering LCIG via tubes is usually advisable as it seems to enhance patients' mobility and therefore has positive outcomes in terms of the quality of life of patients and their families ( Lim et al, 2015 ). The authors aimed to examine the use and consequences of providing nutrition and LCIG via gastrostomy tubes in PD patients with advanced disease.