IPX203 vs Immediate-Release Carbidopa-Levodopa for the Treatment of Motor Fluctuations in Parkinson Disease: The RISE-PD Randomized Clinical Trial.

Importance: Levodopa has a short half-life and a limited window of opportunity for absorption in the proximal small intestine. IPX203 is an oral, extended-release formulation of carbidopa-levodopa developed to address these limitations. Objective: To assess the efficacy and safety of IPX203 vs immediate-release carbidopa-levodopa in patients with Parkinson disease who are experiencing motor fluctuations. Design, Setting, and Participants: RISE-PD was a 20-week, randomized, double-blind, double-dummy, active-controlled, phase 3 clinical trial. The study was conducted between November 6, 2018, and June 15, 2021, at 105 academic and clinical centers in the US and Europe. Patients with Parkinson disease taking a total daily dose of 400 mg or more of levodopa and experiencing an average of 2.5 hours or more daily off-time were included in the study. A total of 770 patients were screened, 140 were excluded (those taking controlled-release carbidopa-levodopa apart from a single daily bedtime dose, Rytary (Amneal Pharmaceuticals), additional carbidopa or benserazide, or catechol O-methyl transferase inhibitors or who had a history of psychosis within the past 10 years), and 630 were enrolled in the trial. Interventions: Following open-label immediate-release carbidopa-levodopa dose adjustment (3 weeks) and conversion to IPX203 (4 weeks), patients were randomized in a 1:1 ratio to double-blind, double-dummy treatment with immediate-release carbidopa-levodopa or IPX203 for 13 weeks. Main Outcome and Measures: The primary end point was mean change in daily good on-time (ie, on-time without troublesome dyskinesia) from baseline to the end of the double-blind treatment period. Results: A total of 630 patients (mean [SD] age, 66.5 [8.95] years; 396 [62.9%] men) were enrolled, and 506 patients were randomly assigned to receive IPX203 (n = 256) or immediate-release carbidopa-levodopa (n = 250). The study met its primary end point, demonstrating statistically significant improvement in daily good on-time for IPX203 compared to immediate-release carbidopa-levodopa (least squares mean, 0.53 hours; 95% CI, 0.09-0.97; P = .02), with IPX203 dosed a mean 3 times per day vs 5 times per day for immediate-release carbidopa-levodopa. Good on-time per dose increased by 1.55 hours with IPX203 compared to immediate-release carbidopa-levodopa (95% CI, 1.37-1.73; P < .001). IPX203 was well tolerated. The most common adverse events in the double-blind phase (IPX203 vs immediate-release carbidopa-levodopa) were nausea (4.3% vs 0.8%) and anxiety (2.7% vs 0.0%). Conclusions and Relevance: In this study, IPX203 provided more hours of good on-time per day than immediate-release carbidopa-levodopa, even as IPX203 was dosed less frequently. Trial Registration: ClinicalTrials.gov Identifier: NCT03670953.

Subcutaneous Levodopa Infusion for Parkinson's Disease: 1-Year Data from the Open-Label BeyoND Study.

BACKGROUND: Continuous, subcutaneous (SC) levodopa/carbidopa infusion with ND0612 is under development as a treatment for patients with Parkinson's disease (PD) and motor fluctuations. OBJECTIVE: Evaluate 1-year safety data. METHODS: BeyoND is an open-label study evaluating the long-term safety of two ND0612 dosing regimens. RESULTS: Of the 214 enrolled patients (24-hour SC infusion: n = 90; 16-hour SC infusion: n = 124), 120 (56%) completed 12 months of treatment. Leading causes for study discontinuation were consent withdrawal (19.6%) and adverse events (17.3%). Rates of discontinuation were reduced from 49% to 29% after a protocol revision and retraining. Systemic safety was typical for PD patients treated with levodopa/carbidopa. Most patients experienced infusion site reactions, particularly nodules (30.8%) and hematoma (25.2%), which were judged mostly mild to moderate and led to discontinuation in only 10.3% of the participants. CONCLUSIONS: Subcutaneous levodopa/carbidopa continuous infusion with ND0612 is generally safe, with typical infusion site reactions for SC delivery as the main adverse event. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Continuous Subcutaneous Levodopa Delivery for Parkinson's Disease: A Randomized Study.

BACKGROUND: ND0612 is a continuous, subcutaneous levodopa/carbidopa delivery system in development for patients with Parkinson's disease (PD) experiencing motor fluctuationsObjective:Evaluate the efficacy and safety of two ND0612 dosing regimens in patients with PD. METHODS: This was a 28-day open-label study (NCT02577523) in PD patients with ≥2.5 hours/day of OFF time despite optimized treatment. Patients were randomized to treatment with either a 24-hour infusion (levodopa/carbidopa dose of 720/90 mg) or a 14-hour 'waking-day' infusion (levodopa/carbidopa dose of 538/68 mg plus a morning oral dose of 150/15 mg). Supplemental oral doses of levodopa were permitted for patients in both groups if required. In-clinic assessments of OFF time (primary endpoint) and ON time with or without dyskinesia were determined by a blinded rater over 8 hours (normalized to 16 hours). RESULTS: A total of 38 patients were randomized and 33 (87%) completed the study. Compared to baseline, OFF time for the overall population was reduced by a least squares (LS) mean[95% CI] of 2.0[- 3.3, - 0.7] hours (p = 0.003). ON time with no/mild dyskinesia (no troublesome dyskinesia) was increased from baseline by a LS mean of 3.3[2.0, 4.6] hours (p < 0.0001), and ON time with moderate/severe dyskinesia was reduced by a LS mean of 1.2[- 1.8, - 0.5] hours (p≤0.001). Reduction in OFF time was larger in the 24-hour group (- 2.8[- 4.6, - 0.9] hours; p = 0.004) than in the 14-hour group (- 1.3[- 3.1, 0.5] hours; p = 0.16). Complete resolution of OFF time was observed in 42% (n = 8) of patients in the 24-hour group. Infusion site reactions were the most common adverse event. CONCLUSION: This study demonstrates the feasibility and safety of continuous subcutaneous delivery of levodopa as a treatment for PD and provides preliminary evidence of efficacy.

Crossover comparison of IPX066 and a standard levodopa formulation in advanced Parkinson's disease.

The objective of the study was to compare the pharmacokinetics, motor effects, and safety of IPX066, a novel extended-release formulation of carbidopa-levodopa, with an immediate-release carbidopa-levodopa formulation in advanced Parkinson's disease. We performed an open-label crossover study in 27 subjects with advanced Parkinson's disease experiencing motor fluctuations on levodopa therapy. Subjects were randomized 1:1 to 8 days' treatment with either immediate-release carbidopa-levodopa followed by IPX066 or IPX066 followed by immediate-release carbidopa-levodopa. Pharmacokinetic and motor assessments were undertaken on day 1 for 8 hours (following a single dose) and on day 8 for 12 hours (during multiple-dose administration). Following a single dose of IPX066 or immediate-release carbidopa-levodopa, plasma levodopa concentrations increased at a similarly rapid rate and were sustained above 50% of peak concentration for 4 hours with IPX066 versus 1.4 hours with immediate-release carbidopa-levodopa (P < .0001). Multiple-dose data showed IPX066 substantially reduced variability in plasma levodopa concentrations despite a lower dosing frequency (mean, 3.5 vs 5.4 administrations per day). In addition, total levodopa exposure during IPX066 treatment was approximately 87% higher, whereas the increase in levodopa C(max) was approximately 30% compared with immediate-release carbidopa-levodopa. Both products were well tolerated. IPX066 provided more sustained plasma levodopa concentrations than immediate-release carbidopa-levodopa. Larger, longer-term, well-controlled studies should be conducted to provide rigorous assessment of the clinical effects of IPX066.

A 52-week study of gabapentin enacarbil in restless legs syndrome.

OBJECTIVES: This open-label, multicenter, 52-week extension study (NCT00333359) assessed the long-term safety and efficacy of gabapentin enacarbil in subjects with moderate-to-severe primary restless legs syndrome (RLS). METHODS: Subjects had completed one of 4 randomized, double-blind parent studies (XP052/XP053/XP081/XP083). Gabapentin enacarbil 1200 mg was administered once daily at 5 pm; dose adjustments to 600 or 1800 mg were permitted based on investigator judgment. Safety assessments included adverse events (AEs), vital signs, clinical laboratory tests, and electrocardiograms. Efficacy evaluations included the International Restless Legs Scale total score and the investigator-rated Clinical Global Impression-Improvement scale, at week 52 last observation carried forward. RESULTS: The safety population comprised 573 subjects; 386 (67.4%) completed the study. Treatment-emergent AEs were reported by 80.1% of subjects and led to withdrawal in 10.3% of subjects; most (67.7%) were mild or moderate in intensity. The most common AEs were somnolence and dizziness (19.7% and 11.5% of subjects). Twenty subjects (3.5%) reported serious AEs; one subject died (fall, 25 days after stopping gabapentin enacarbil, judged not treatment related). No serious AE occurred in more than 1 subject. No clinically relevant changes were reported in vital signs, laboratory parameters, or electrocardiograms. At week 52 last observation carried forward, the mean (SD) change from parent study baseline in International Restless Legs Scale total score was -15.2 (8.85 [parent study baseline score, 23.2 (5.03)]), and 84.8% of subjects were Clinical Global Impression-Improvement responders ("much improved" or "very much improved"). CONCLUSIONS: Gabapentin enacarbil was generally safe and well tolerated and improved RLS symptoms in subjects with moderate-to-severe primary RLS for up to 64 weeks of treatment.

Gabapentin enacarbil in restless legs syndrome: a phase 2b, 2-week, randomized, double-blind, placebo-controlled trial.

OBJECTIVES: Assess the efficacy and tolerability of gabapentin enacarbil (GEn), a transported prodrug of gabapentin with improved gabapentin exposure, in adults with moderate-to-severe primary restless legs syndrome. METHODS: This 14-day, double-blind, randomized, controlled trial of GEn at 1200 or 600 mg or placebo taken once daily, evaluated the mean change from baseline International Restless Legs Scale (IRLS) total score at end of treatment (day 14:primary comparison, GEn at 1200 mg vs placebo). Secondary end points included Clinical Global Impression-Improvement scale outcomes at day 14. RESULTS: Ninety-five subjects were randomized (GEn: 1200 mg, n = 33 and 600 mg, n = 29; placebo, n = 33); 2 subjects (GEn at 1200 mg) withdrew because of adverse events. At day 14,the mean (SD) change from baseline IRLS total score was significantly greater with GEn at 1200 mg (-16.1 [7.93]) compared with placebo (-8.9 [7.72]; adjusted mean treatment difference, -7.2; P < 0.0001). Investigator-rated Clinical Global Impression-Improvement scale responses also significantly favored GEn at 1200 mg compared with placebo (P G 0.0001).The mean (SD) change from baseline IRLS total score with GEn at 600 mg at day 14 was -9.1 (5.95), similar to placebo. The most commonly reported treatment-emergent adverse events were somnolence (GEn: 1200 mg, 36% and 600 mg, 14%; placebo,15%) and dizziness (GEn: 1200 mg, 18% and 600 mg, 14%; placebo, 3%), most of which were rated mild or moderate in intensity. CONCLUSIONS: Gabapentin enacarbil at 1200 mg significantly improved restless legs syndrome symptoms compared with placebo. Efficacy outcomes for GEn at 600 mg were similar to placebo. Both GEn doses were generally well tolerated.