Motor Efficacy of Subcutaneous DIZ102, Intravenous DIZ101 or Intestinal Levodopa/Carbidopa Infusion.

BACKGROUND: It has been suggested that carbidopa at high blood concentrations may counter the therapeutic effect of levodopa in Parkinson's disease by entering the brain and blocking central levodopa conversion to dopamine. We previously demonstrated equivalent plasma levodopa concentration in patients with Parkinson's disease during 16 h of (1) intravenous carbidopa/levodopa (DIZ101) infusion, (2) subcutaneous carbidopa/levodopa (DIZ102) infusion or (3) intestinal carbidopa/levodopa gel infusion. Plasma levels of carbidopa were however approximately four times higher with DIZ101 and DIZ102 than with LCIG, and higher than those usually observed with oral levodopa/carbidopa. OBJECTIVES: To investigate if high carbidopa blood concentrations obtained with parenteral levodopa/carbidopa (ratio 8:1) counter the effect of levodopa on motor symptoms. METHODS: Eighteen patients with advanced Parkinson's disease were administered DIZ101, DIZ102, and intestinal levodopa/carbidopa gel for 16 h on different days in randomized order. Video recordings of a subset of the motor examination in the Unified Parkinson's Disease Rating Scale (UPDRS) were evaluated by raters blinded for treatment and time. Motor function was also measured using a wrist-worn device monitoring bradykinesia, dyskinesia, and tremor (Parkinson KinetiGraph). RESULTS: There was no tendency for poorer levodopa effect with DIZ101 or DIZ102 as compared to LCIG. CONCLUSION: Although DIZ101 or DIZ102 causes approximately four times higher plasma carbidopa levels than LCIG, patients responded equally well to all treatments. The results do not indicate that high plasma carbidopa levels hamper the motor efficacy of levodopa.

Pharmacokinetics of Intravenously (DIZ101), Subcutaneously (DIZ102), and Intestinally (LCIG) Infused Levodopa in Advanced Parkinson Disease.

BACKGROUND AND OBJECTIVES: Intestinal levodopa/carbidopa gel infusion (LCIG) is superior to oral treatment in advanced Parkinson's disease. The primary objectives of this trial were to investigate if continuous subcutaneous or intravenous infusion with a continuously buffered acidic levodopa/carbidopa solution yields steady state plasma concentrations of levodopa that are equivalent in magnitude, and non-inferior in variability, to those obtained with LCIG in patients with advanced Parkinson's disease. METHODS: A concentrated acidic levodopa/carbidopa (8:1) solution buffered continuously and administered intravenously (DIZ101) or subcutaneously (DIZ102) was compared with an approved intestinal levodopa/carbidopa gel (LCIG) in a randomized, 3-period cross-over, open-label multicenter trial. Formulations were infused for 16h to patients with Parkinson's disease who were using LCIG as their regular treatment. Patients were recruited at several university neurology clinics but came to the same phase I unit for treatment. Pharmacokinetic variables and safety including dermal tolerance are reported. The primary outcomes were bioequivalence and non-inferior variability of DIZ101 and DIZ102 versus LCIG with respect to levodopa plasma concentrations. RESULTS: With dosing adjusted to estimated bioavailability, DIZ101 and DIZ102 produced levodopa plasma levels within standard bioequivalence limits when compared to LCIG in the 18 participants that received all treatments. While the levodopa bioavailability for DIZ102 was complete, it was 80% for LCIG. Therapeutic concentrations of levodopa were reached as quickly with subcutaneous administration of DIZ102 as with LCIG and remained stable throughout the infusions. Due to poor uptake with LCIG, carbidopa levels in plasma were higher with DIZ101 and DIZ102 than with the former. All individuals receiving any of the treatments (n=20) were included in the evaluation of safety and tolerability. Reactions at the infusion sites were mild and transient. DISCUSSION: It is feasible to rapidly achieve high and stable levodopa concentrations by means of continuous buffering of a subcutaneously administered acidic levodopa/carbidopa containing solution. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov Identifier: NCT03419806. Registration first posted 5 Feb 2018, first patient enrolled 16 Feb 2018. Link to registration.

Pharmacokinetics of levodopa/carbidopa microtablets versus levodopa/benserazide and levodopa/carbidopa in healthy volunteers.

OBJECTIVES: To compare bioavailability and pharmacokinetics of single doses of 3 different levodopa formulations given orally in healthy volunteers. Two marketed formulations, standard levodopa/carbidopa, 100/25 mg (LC-100), and dispersible levodopa/benserazide, 100/25 mg (LB-100), were used as reference formulations for a newly developed dispersible microtablet formulation of levodopa/carbidopa, 5/1.25 mg (LC-5). The microtablets are intended for individualized dosing of levodopa/carbidopa in Parkinson disease by means of an electronic dose dispenser with a built-in diary for symptom registration. METHODS: A single-dose, open, randomized, 3-way crossover study was performed in 19 healthy subjects. Concentrations of levodopa, carbidopa, and the metabolite 3-O-MD in plasma were determined after intake of 100 mg of levodopa, that is, one tablet of reference formulations and 20 microtablets of the new formulation. RESULTS: The LC-5 microtablets were bioequivalent to the LC-100 tablets in area under the curve (AUC) and maximum concentration in plasma (Cmax) for levodopa, and to the LB-100 tablets in AUC. The dispersible levodopa/benserazide formulation showed earlier time to Cmax and significantly higher Cmax for levodopa in plasma compared to the microtablets. Carbidopa showed larger interindividual variation in AUC and Cmax than levodopa, and the bioequivalence comparison LC-5/LC-100 for this compound did not reach the target. Nevertheless, comparison of 3-O-MD levels for LC-5/LC-100, assuming proportionality to levodopa levels, demonstrated bioequivalence. CONCLUSIONS: The new levodopa/carbidopa microtablets had a pharmacokinetic profile that would allow for a convenient switch of therapy from standard tablets. Frequent dose administration of levodopa/carbidopa microtablets with an electronic dose dispenser might offer an optimal oral drug delivery in Parkinson disease.

Seeking evidence that cell kill guided thermotherapy gives results not inferior to those of transurethral prostate resection: results of a pooled analysis of 3 studies of feedback transurethral microwave thermotherapy.

PURPOSE: We compared ProstaLund Feedback Treatment (PLFT) to transurethral prostate resection (TURP) in terms of efficacy and safety in a pooled analysis of 3 clinical studies with 1-year followup. MATERIALS AND METHODS: Overall raw data on 183 patients with PLFT and 65 with TURP were pooled. All studies had identical inclusion criteria, and the efficacy and safety of the method were evaluated using the International Prostate Symptom Score, maximum urine flow (Qmax), responder rate, bother score, prostate volume reduction and adverse events. RESULTS: The response rate was 85.3% and 85.9% in the PLFT and TURP groups, respectively. One-sided 95% CI analysis showed the noninferiority of PLFT vs TURP for this variable. Mean International Prostate Symptom Score was significantly decreased in the PLFT and TURP groups after 12 months (from 20.9 to 6.4 and 20.7 to 7.1, respectively). The 1-sided upper 95% CI of PLFT was within the noninferiority definition compared with that of TURP. The bother score decrease in the PLFT and TURP groups was not significant different (70.9% and 64.0%, respectively). An increase in Qmax from 7.7 to 16.1 ml per second 12 months after PLFT was noted, while the improvement in Qmax in the TURP group was higher (from 7.5 to 18.6 ml per second). The 1-sided lower 95% CI was close (0.76) but it did not attain the predetermined level of noninferiority (0.80). Mean transurethral ultrasound determined volume 12 months after PLFT and TURP was reduced by 32.8% and 58.1%, respectively. A significant correlation between the transurethral ultrasound determined prostate volume reduction and estimated cell kill was found (r = 0.456, p <0.000001). Serious adverse events with causality occurred in 15.4% of patients with TURP compared with 6.0% in those with PLFT (p = 0.035). CONCLUSIONS: Combined experience from our pooled analysis indicates that PLFT challenges TURP in terms of efficacy and safety after 1 year of followup.