Clinical Pharmacokinetics of IPX066: Evaluation of Dose Proportionality and Effect of Food in Healthy Volunteers

How to Optimize the Effectiveness and Safety of Parkinson's Disease Therapy? - A Systematic Review of Drugs Interactions with Food and Dietary Supplements

BACKGROUND

Despite increasing worldwide incidence of Parkinson's disease, the therapy is still suboptimal due to the diversified clinical manifestations, lack of sufficient treatment, the poor adherence in advanced patients, and varied response. Proper intake of medications regarding food and managing drug-food interactions may optimize Parkinson's disease treatment.

OBJECTIVES

We investigated potential effects that food, beverages, and dietary supplements may have on the pharmacokinetics and pharmacodynamics of drugs used by parkinsonian patients; identified the most probable interactions; and shaped recommendations for the optimal intake of drugs regarding food.

METHODS

We performed a systematic review in adherence to PRISMA guidelines, and included a total of 81 studies in the qualitative synthesis.

RESULTS AND CONCLUSION

We found evidence for levodopa positive interaction with coffee, fiber and vitamin C, as well as for the potential beneficial impact of low-fat and protein redistribution diet. Contrastingly, high-protein diet and ferrous sulfate supplements can negatively affect levodopa pharmacokinetics and effectiveness. For other drugs, the data of food impact are scarce. Based on the available limited evidence, all dopamine agonists (bromocriptine, cabergoline, ropinirole), tolcapone, rasagiline, selegiline in tablets, safinamide, amantadine and pimavanserin can be taken with or without a meal. Opicapone and orally disintegrating selegiline tablets should be administered on an empty stomach. Of monoamine oxidase B inhibitors, safinamide is the least susceptible for interaction with the tyramine-rich food, whereas selegiline and rasagiline may lose selectivity to monoamine oxidase B when administered in supratherapeutic doses. The level of presented evidence is low due to the poor studies design, their insufficient actuality, and missing data.

Therapeutic Strategies to Treat or Prevent Off Episodes in Adults with Parkinson's Disease

Parkinson's disease is a chronic, neurodegenerative disease, which manifests with a mixture of motor, cognitive and behavioural symptoms. Levodopa is the most effective antiparkinsonian treatment to date, although chronic use engenders a mixture of complications in a substantial proportion of patients. Amongst these is the occurrence of episodes of worsening symptoms-'off' phenomena. These episodes can manifest with either motor or non-motor symptoms or a combination of these features and have been found to have profound impacts on patients' quality of life. Although preventative measures are poorly evidenced, avoiding excessive total daily levodopa intake in selected populations that are deemed to be of a higher risk for developing these episodes warrants further exploration. Methods to improve levodopa bioavailability and delivery to the brain are currently available and are of value in addressing these episodes once they have become established. These include modifications to levodopa formulations as well as the use of complimentary agents that improve levodopa bioavailability. The deployment of device-assisted approaches is a further dimension that can be considered in addressing these debilitating episodes. This review summarises the clinical manifestations of 'off' phenomena and the current approaches to treat them. Although we briefly discuss clinical advances on the horizon, the predominant focus is on existing, established treatments.

Medical Management and Prevention of Motor Complications in Parkinson's Disease

Levodopa is the most effective medication for the treatment of the motor symptoms of Parkinson's disease. However, over time, the clinical response to levodopa becomes complicated by a reduction in the duration and reliability of motor improvement (motor fluctuations) and the emergence of involuntary movements (levodopa-induced dyskinesia). Strategies that have been attempted in an effort to delay the development of these motor complications include levodopa sparing and continuous dopaminergic therapy. Once motor complications occur, a wide array of medical treatments is available to maximize motor function through the day while limiting dyskinesia. Here, we review the clinical features, epidemiology, and risk factors for the development of motor complications, as well as strategies for their prevention and medical management.

Contemporary Options for the Management of Motor Complications in Parkinson's Disease: Updated Clinical Review

Parkinson's disease (PD) is a chronic, progressive condition affecting around 1% of the population older than 60 years. Upon long-term treatment with levodopa, the mainstay of treatment in PD, most patients, especially younger ones exposed to higher doses, will experience symptoms related to end-of-dose deterioration, peak-dose dyskinesias, and other motor fluctuations. Therapeutic strategies are grounded on modification of oral levodopa pharmacokinetics to extend levodopa benefit and development of new routes of drug delivery (e.g., levodopa/carbidopa intestinal gel infusion) or long-acting formulations of existing dopaminergic drugs to prolong the duration of striatal dopamine receptors stimulation. As our understanding of the pathophysiology of motor complications evolves, our therapeutic armamentarium is actively expanding and the focus of research is now actively pointing to the new non-dopaminergic agents acting both within the basal ganglia and in other brain regions (e.g., drugs acting on glutamate, GABA, serotonin, and calcium channels). Despite the fact that trials comparing the different therapeutic strategies are lacking, we aimed at devising practical evidence- and experience-guided suggestions for the clinical management of motor complications, emphasizing that this should always be an individualized endeavor. This review summarizes the pharmacological management of motor complications in PD, including new formulations and routes of delivery, and the newer released drugs such as istradefylline, opicapone, safinamide, and zonisamide. Advanced therapeutic strategies for selected cases such as treatment with apomorphine and surgical techniques (deep brain stimulation) are also discussed. A comprehensive knowledge of the available options and evidence is fundamental for the successful management of these challenging complications.

A Pharmacokinetic Bioequivalence Study Comparing Sublingual Riluzole (BHV-0223) and Oral Tablet Formulation of Riluzole in Healthy Volunteers

Orally administered riluzole extends survival in patients with amyotrophic lateral sclerosis, although it has significant shortcomings (eg, adverse events, dysphagic patients) that limit its utility. BHV-0223 is a Zydis-based orally disintegrating formulation of riluzole designed for sublingual administration that addresses the limitations of conventional tablets. This study assessed the bioequivalence between 40-mg BHV-0223 and standard 50-mg oral riluzole tablets, and the food effect on BHV-0223 pharmacokinetics in healthy volunteers. Overall, 133 healthy subjects received BHV-0223 and riluzole tablets under fasted conditions. Geometric mean ratios for the area under the plasma concentration-time curve (AUC) from time zero to time of last nonzero concentration (AUC_0-t ) (89.9%; confidence interval [CI], 87.3%-92.5%), AUC from time zero to infinity (AUC_0-∞ ) (89.8%; CI, 87.3%-92.4%), and maximum observed concentration (112.7%; CI, 105.5%-120.4%) all met bioequivalence criteria (80%-125%). Subsequently, 67 subjects received BHV-0223 under fed conditions. The geometric mean ratios of AUC_0-t (91.2%; CI, 88.1-94.3%), and AUC_0-∞ (92.0%; CI, 89.0-95.1%) were similar, but maximum observed concentration ratios were not within bioequivalence criteria. BHV-0223 was well tolerated. This study demonstrated that 40-mg sublingual BHV-0223 is bioequivalent to 50-mg oral riluzole tablets.

From medications to surgery: advances in the treatment of motor complications in Parkinson's disease

Motor complications are responsible for the large burden of disability and poor quality of life in Parkinson’s disease (PD). The pulsatile nature of stimulation with oral dopaminergic therapies due to relatively short pharmacokinetic profiles and dysfunctional gastrointestinal absorption have been attributed to the development of PD motor complications. In this review, we will provide an overview of the pharmacologic and surgical therapies currently available and under investigation for the treatment of motor fluctuations and dyskinesia.

Pharmacokinetics of Rytary®, An Extended-Release Capsule Formulation of Carbidopa-Levodopa

Parkinson's disease (PD) is a chronic progressive neurological disorder characterized by resting tremor, rigidity, bradykinesia, gait disturbance, and postural instability. Levodopa, the precursor to dopamine, coadministered with carbidopa or benserazide, aromatic amino acid decarboxylase inhibitors, is the most effective and widely used therapeutic agent in the treatment of PD. With continued levodopa treatment, a majority of patients develop motor complications such as dyskinesia and motor 'on-off' fluctuations, which are, in part, related to the fluctuations in plasma concentrations of levodopa. A new extended-release (ER) carbidopa-levodopa capsule product (also referred to as IPX066) was developed and approved in the US as Rytary^® and in the EU as Numient^®. The capsule formulation is designed to provide an initial rapid absorption of levodopa comparable to immediate-release (IR) carbidopa-levodopa, and to subsequently provide stable levodopa concentrations with reduced peak-to-trough excursions in plasma concentrations in order to reduce motor fluctuations associated with pulsatile stimulation of dopamine receptors and to minimize dyskinesia. Phase III studies of this ER carbidopa-levodopa capsule formulation in patients with PD have shown a significant reduction in 'off' time compared with IR carbidopa-levodopa and carbidopa-levodopa-entacapone. We present a review of the clinical pharmacokinetics and pharmacodynamics of this ER product of carbidopa-levodopa in healthy subjects and in patients with PD.

Effect of Concomitant Medications on the Safety and Efficacy of Extended-Release Carbidopa-Levodopa (IPX066) in Patients With Advanced Parkinson Disease: A Post Hoc Analysis

OBJECTIVES

Extended-release (ER) carbidopa-levodopa (CD-LD) (IPX066/RYTARY/NUMIENT) produces improvements in "off" time, "on" time without troublesome dyskinesia, and Unified Parkinson Disease Rating Scale scores compared with immediate-release (IR) CD-LD or IR CD-LD plus entacapone (CLE). Post hoc analyses of 2 ER CD-LD phase 3 trials evaluated whether the efficacy and safety of ER CD-LD relative to the respective active comparators were altered by concomitant medications (dopaminergic agonists, monoamine oxidase B [MAO-B] inhibitors, or amantadine).

METHODS

ADVANCE-PD (n = 393) assessed safety and efficacy of ER CD-LD versus IR CD-LD. ASCEND-PD (n = 91) evaluated ER CD-LD versus CLE. In both studies, IR- and CLE-experienced patients underwent a 6-week, open-label dose-conversion period to ER CD-LD prior to randomization. For analysis, the randomized population was divided into 3 subgroups: dopaminergic agonists, rasagiline or selegiline, and amantadine. For each subgroup, changes from baseline in PD diary measures ("off" time and "on" time with and without troublesome dyskinesia), Unified Parkinson Disease Rating Scale Parts II + III scores, and adverse events were analyzed, comparing ER CD-LD with the active comparator.

RESULTS AND CONCLUSIONS

Concomitant dopaminergic agonist or MAO-B inhibitor use did not diminish the efficacy (improvement in "off" time and "on" time without troublesome dyskinesia) of ER CD-LD compared with IR CD-LD or CLE, whereas the improvement with concomitant amantadine failed to reach significance. Safety and tolerability were similar among the subgroups, and ER CD-LD did not increase troublesome dyskinesia. For patients on oral LD regimens and taking a dopaminergic agonist, and/or a MAO-B inhibitor, changing from an IR to an ER CD-LD formulation provides approximately an additional hour of "good" on time.

Extended-release oral capsule of carbidopa-levodopa in Parkinson disease

Motor fluctuations complicate the treatment of patients with Parkinson's disease receiving levodopa. Extended-release carbidopa-levodopa has a pharmacokinetic profile that provides a more continuous levodopa serum concentration. Patients taking this formulation can expect longer duration of action and fewer doses per day, similar clinical improvement when compared to other levodopa formulations, and with a theoretically lower risk of developing motor fluctuations. Several studies, including three randomized control trials provide evidence for the efficacy, safety and tolerability of extended release carbidopa-levodopa in patients with both early and advanced Parkinson's disease are reviewed here. Also provided is guidance for dosing of and conversion to extended release carbidopa-levodopa as well as a discussion of its place in the clinical practice.

Biopharmaceutical Evaluation and CMC Aspects of Oral Modified Release Formulations

This article discusses the range of outcomes from biopharmaceutical studies of specific modified release (MR) product examples in preclinical models and humans. It touches upon five major biopharmaceutical areas for MR drug products: (1) evidence for regional permeability throughout the GI tract, (2) susceptibility to food-effect, (3) susceptibility to pH-effect, (4) impact of chronopharmacology in designing MR products, and (5) implications to narrow therapeutic index products. Robust bioperformance requires that product quality is met through a thorough understanding of the appropriate critical quality attributes that ensure reliable and robust manufacture of a MR dosage form. The quality-by-design (QbD) aspects of MR dosage form design and development are discussed with the emphasis on the regulatory view of the data required to support dosage form development.

Recent advances in treating Parkinson's disease

This article summarizes (1) the recent achievements to further improve symptomatic therapy of motor Parkinson’s disease (PD) symptoms, (2) the still-few attempts to systematically search for symptomatic therapy of non-motor symptoms in PD, and (3) the advances in the development and clinical testing of compounds which promise to offer disease modification in already-manifest PD. However, prevention (that is, slowing or stopping PD in a prodromal stage) is still a dream and one reason for this is that we have no consensus on primary endpoints for clinical trials which reflect the progression in prodromal stages of PD, such as in rapid eye movement sleep behavior disorder (RBD) —a methodological challenge to be met in the future.

Application of Pharmacokinetics and Pharmacodynamics in Product Life Cycle Management. A Case Study with a Carbidopa-Levodopa Extended-Release Formulation

Increasing costs in discovering and developing new molecular entities and the continuing debate on limited company pipelines mean that pharmaceutical companies are under significant pressure to maximize the value of approved products. Life cycle management in the context of drug development comprises activities to maximize the effective life of a product. Life cycle approaches can involve new formulations, new routes of delivery, new indications or expansion of the population for whom the product is indicated, or development of combination products. Life cycle management may provide an opportunity to improve upon the current product through enhanced efficacy or reduced side effects and could expand the therapeutic market for the product. Successful life cycle management may include the potential for superior efficacy, improved tolerability, or a better prescriber or patient acceptance. Unlike generic products where bioequivalence to an innovator product may be sufficient for drug approval, life cycle management typically requires a series of studies to characterize the value of the product. This review summarizes key considerations in identifying product candidates that may be suitable for life cycle management and discusses the application of pharmacokinetics and pharmacodynamics in developing new products using a life cycle management approach. Examples and a case study to illustrate how pharmacokinetics and pharmacodynamics contributed to the selection of dosing regimens, demonstration of an improved therapeutic effect, or regulatory approval of an improved product label are presented.

Novel Levodopa Formulations for Parkinson's Disease

Levodopa remains the most effective treatment for Parkinson's disease and is considered the gold standard therapy. However, disease progression and changes in the gastrointestinal tract result in a declining window of treatment response in a majority of patients. Efforts have been made recently to improve levodopa bioavailability either by developing more effective oral formulations or by innovating routes of administration (intestinal infusion, transcutaneous or inhaled levodopa). IPX066 is a novel levodopa-carbidopa (LD/CD) oral formulation combining immediate-release (IR) and extended-release (ER) LD/CD recently approved in the USA and the EU. Levodopa-carbidopa intestinal gel (LCIG) is an approved therapy consisting of a suspension of levodopa and carbidopa infused directly into the proximal jejunum via a percutaneous endoscopic gastrojejunostomy (PEG-J) tube through a portable infusion pump. Ongoing studies are evaluating the 'accordion pill' (AP09004), an ER LD/CD formulation with gastroretentive properties. ND0612 is a proprietary liquid formulation of LD/CD that enables subcutaneous administration via a small patch-pump device, and CVT-301 is a levodopa inhalation powder with rapid onset of action; both are currently in active studies. Other novel formulations have been discontinued, including DM-1992, which is a bilayer formulation containing an IR LD/CD layer and an ER LD/CD layer with gastroretentive properties, and XP21279, a novel oral levodopa prodrug that is absorbed from the small and large intestine by high-capacity nutrient transporters expressed throughout the gastrointestinal system. ODM-101 is a new oral formulation of levodopa/carbidopa/entacapone that contains a higher amount of carbidopa (65 or 105 mg), but no active studies are underway. The current review aims to summarize the pharmacokinetic aspects, clinical efficacy, and potential adverse events of novel levodopa formulations currently available or under development.

Physicians' experience with RYTARY (carbidopa and levodopa) extended-release capsules in patients who have Parkinson disease

A discussion between Dr. Dee Silver and Dr. Richard Trosch provides insight and advice for physicians considering a switch from immediate-release carbidopa-levodopa (IR CD-LD) to RYTARY as a treatment for patients with Parkinson disease (PD). The dialogue describes how they identify patients with PD who may and may not be successful switching to RYTARY, how they approach the conversion process and patient compliance, and how they address some side effects that may occur after patients begin taking RYTARY. The clinicians also discuss their experiences with how long it takes to establish a stable regimen as well as provide general advice regarding conversion from treatment with IR CD-LD to RYTARY.

Carbidopa/Levodopa ER Capsules (Rytary(®), Numient™): A Review in Parkinson's Disease

A new extended-release (ER) capsule formulation of carbidopa/levodopa (Rytary(®), Numient™, IPX066) is available for the treatment of Parkinson's disease (PD). Carbidopa/levodopa ER capsules contain beads of carbidopa and levodopa, designed to release the drugs at different rates in the gastrointestinal tract and provide constant therapeutic levodopa concentrations that are maintained for 4-5 h (after an initial peak at ≈ 1 h). In randomized phase III trials, oral carbidopa/levodopa ER was significantly more effective than placebo with regard to improving motor symptoms and activities of daily living in patients with early PD after 30 weeks' treatment, and provided significantly greater reductions in daily 'off-time' in patients with advanced PD than immediate-release (IR) carbidopa/levodopa or carbidopa/levodopa IR plus entacapone after a treatment period of 13 and 2 weeks, respectively, without increasing troublesome dyskinesia. The efficacy of carbidopa/levodopa ER was maintained during a 9-month open-label extension in patients with early or advanced PD. Carbidopa/levodopa ER was generally well tolerated in clinical trials, with the most common adverse events in the extension study being nausea and insomnia in patients with early PD and falls and dyskinesia in patients with advanced PD. Thus, carbidopa/levodopa ER is an effective and generally well-tolerated treatment option for the motor symptoms of PD, reducing periods of 'off-time' compared with carbidopa/levodopa IR without increasing troublesome dyskinesia.