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LCE vs LB

Comparison of blood dopamine in Parkinson's patients treated with levodopa carbidopa entacapone vs levodopa benserazide: A randomized controlled trial

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Year of Publication: 2026

Authors: Korucu O, Özdemir S, Türkeş GF, ..., Emektar E

Journal: Medicine (Baltimore)

Citation: Medicine (Baltimore) 2026;105(21):e48895

Link: https://doi.org/10.1097/MD.0000000000048895

Bottom Line

In 90 patients with Hoehn & Yahr stage 1-1.5 Parkinson's disease, a single dose of LCE and LB produced similar plasma dopamine elevations at 90 and 180 minutes, with no significant between-group or intragroup differences, suggesting comparable short-term biochemical efficacy.

        Major Points
        Prospective, randomized, single-center phase 4 trial conducted in Ankara, Türkiye (Oct 2023-Oct 2024) enrolling 90 patients with early-stage unilateral Parkinson's disease (Hoehn & Yahr 1-1.5).
Plasma dopamine measured by ELISA at 0, 90, and 180 minutes after a single oral dose of either LCE (100/25/200 mg) or LB (100/25 mg).
No significant difference between LCE and LB in plasma dopamine at any time point (all P > .70).
Both groups showed modest, non-significant rises in dopamine over 180 minutes (LCE P=.355; LB P=.097).
Authors conclude both regimens have comparable short-term biochemical efficacy in early-stage PD; differences may not yet emerge before substantial dopaminergic neuronal loss.
Limitations: short 180-minute follow-up, no motor or adverse-event outcomes captured, single-center design, possible ELISA cross-reactivity with 3-O-methyldopa.

      

Design

Study Type: Randomized Controlled Trial (single-dose pharmacodynamic, phase 4)

Randomization: 1

Blinding: Open-label (not specified as blinded)

Enrollment Period: October 2023 - October 2024

Follow-up Duration: 180 minutes (single-dose)

Centers: 1

Countries: Türkiye

Sample Size: 90

Analysis: Per-protocol comparison using Mann-Whitney U (between-group) and Friedman (within-group) tests

Inclusion Criteria

Age 40-75 years
Hoehn and Yahr stage 1-1.5 Parkinson's disease
Had not taken levodopa in the previous 12 hours
Fasted for at least 2 hours before assessment
No use of levodopa, DDC inhibitor, or COMT inhibitor for at least 12 hours
Informed consent provided

Exclusion Criteria

Hoehn and Yahr stage ≥2
Body mass index ≥35 kg/m²
Receiving device-assisted therapies (apomorphine, levodopa-carbidopa intestinal gel, deep brain stimulation)
Presence of dyskinesia
Daily levodopa dose >800 mg
Diagnosis of drug-induced Parkinsonism
Pregnant or breastfeeding

Baseline Characteristics

Characteristic	Overall (N=90)	LCE (n=44)	LB (n=46)
Female	34.4%
Median Age (years)	69.5 (IQR 62-73)
Median BMI (kg/m²)	26.7 (IQR 24.8-29.4)
Median Disease Duration (months)	24 (IQR 12-48)
Tremor-dominant subtype	92.2%
Akinetic-rigid subtype	7.8%
Urban residence (last 10 yr)	90%
Rural residence (last 10 yr)	10%
Education - Primary school	65.6%
Education - High school	17.8%
Education - University	7.8%
Occupation - Retired	57.8%
Occupation - Housewife	33.3%
Proportion of cohort		48.9%	51.1%
Median pre-medication dopamine (ng/mL)		76.7 (IQR 44.4-107.3)	66.4 (IQR 52-92.4)

Arms

Field	LCE	Control
Intervention	Single oral dose of Dopalevo: levodopa 100 mg / carbidopa 25 mg / entacapone 200 mg (Abdi İbrahim Pharmaceuticals)	Single oral dose of Madopar 125 mg: levodopa 100 mg / benserazide 25 mg (F. Hoffmann-La Roche / Deva Holding)
Duration	Single dose, observed over 180 minutes	Single dose, observed over 180 minutes

Outcomes

Outcome	Type	Control	Intervention	P-value
Plasma dopamine concentration (ng/mL) at 0, 90, and 180 minutes after single-dose administration, measured by ELISA	Primary	LB: 66.4 (baseline) → 74.1 (90 min) → 80.8 (180 min) ng/mL	LCE: 76.7 (baseline) → 91.1 (90 min) → 90 (180 min) ng/mL	Between-group: .744 (baseline), .704 (90 min), .750 (180 min). Intragroup over time: LCE P=.355; LB P=.097
Intragroup change in plasma dopamine over time within the LCE group	Secondary	N/A	76.7 → 91.1 → 90 ng/mL	.355 (Friedman test)
Intragroup change in plasma dopamine over time within the LB group	Secondary	66.4 → 74.1 → 80.8 ng/mL	N/A	.097 (Friedman test)
Note	Adverse	Adverse events were not assessed in this single-dose 180-minute biochemical study; authors flag this as a limitation.

Subgroup Analysis

No subgroup analyses by sex, age, disease duration, or motor subtype were reported.

Criticisms

Short observation window (180 minutes after a single dose) cannot capture steady-state pharmacodynamics or the longer half-life advantage of entacapone.
Only plasma dopamine was measured; no motor outcomes (UPDRS, ON/OFF time), quality-of-life, or adverse-event data captured.
ELISA-based dopamine measurement may cross-react with 3-O-methyldopa (3-OMD), which the authors did not exclude experimentally.
Single-center Turkish cohort restricted to early-stage (Hoehn & Yahr 1-1.5) unilateral PD limits generalizability to advanced PD or other populations.
Open-label single-dose design without blinding raises potential bias.
Baseline characteristics not stratified by treatment arm in the published tables, limiting assessment of randomization balance.
Modest sample size (n=90); abstract reports HPLC measurement while methods state ELISA — methodological inconsistency within the manuscript.

Funding

Dopamine ELISA kits supplied by İlko Pharmaceuticals; no other industry funding disclosed.

Based on: LCE vs LB (Medicine (Baltimore), 2026)

Authors: Korucu O, Özdemir S, Türkeş GF, ..., Emektar E

Citation: Medicine (Baltimore) 2026;105(21):e48895

Content summarized and formatted by NeuroTrials.ai.

LCE vs LB

(2026)

Objective

To compare short-term effects of levodopa-carbidopa-entacapone (LCE) versus levodopa-benserazide (LB) on plasma dopamine levels in early-stage unilateral Parkinson's disease.

Study Summary

• No significant difference in plasma dopamine between LCE and LB at baseline (P=.744), 90 min (P=.704), or 180 min (P=.750)
• Both regimens raised dopamine modestly; LCE 76.7 → 91.1 → 90 ng/mL, LB 66.4 → 74.1 → 80.8 ng/mL
• No significant intragroup change over time (LCE P=.355; LB P=.097)
• Suggests comparable biochemical efficacy of the two interchangeable regimens in early-stage PD

Intervention

Single oral dose of LCE (levodopa 100 mg / carbidopa 25 mg / entacapone 200 mg) vs LB (levodopa 100 mg / benserazide 25 mg) with plasma dopamine measured at 0, 90, and 180 minutes.

Inclusion Criteria

Age 40-75 with Hoehn & Yahr stage 1-1.5 Parkinson's disease; no levodopa within 12 hours; fasted ≥2 hours before assessment.

Study Design

Arms: LCE (levodopa-carbidopa-entacapone) vs LB (levodopa-benserazide), randomized 1:1.

Patients per Arm: LCE n=44; LB n=46 (total 90)

Outcome

• Plasma dopamine at 90 min: 91.1 (LCE) vs 74.1 ng/mL (LB), P=.704
• Plasma dopamine at 180 min: 90 (LCE) vs 80.8 ng/mL (LB), P=.750
• Intragroup change over time non-significant (LCE P=.355; LB P=.097)
• Adverse events not assessed in this single-dose pharmacodynamic study

Clinical Question

Do levodopa-carbidopa-entacapone (LCE) and levodopa-benserazide (LB) differ in their short-term effect on plasma dopamine levels in patients with early-stage unilateral Parkinson's disease?

Bottom Line

Major Points

Prospective, randomized, single-center phase 4 trial conducted in Ankara, Türkiye (Oct 2023-Oct 2024) enrolling 90 patients with early-stage unilateral Parkinson's disease (Hoehn & Yahr 1-1.5).
Plasma dopamine measured by ELISA at 0, 90, and 180 minutes after a single oral dose of either LCE (100/25/200 mg) or LB (100/25 mg).
No significant difference between LCE and LB in plasma dopamine at any time point (all P > .70).
Both groups showed modest, non-significant rises in dopamine over 180 minutes (LCE P=.355; LB P=.097).
Authors conclude both regimens have comparable short-term biochemical efficacy in early-stage PD; differences may not yet emerge before substantial dopaminergic neuronal loss.
Limitations: short 180-minute follow-up, no motor or adverse-event outcomes captured, single-center design, possible ELISA cross-reactivity with 3-O-methyldopa.

Study Design

Study Type: Randomized Controlled Trial (single-dose pharmacodynamic, phase 4)
Randomization: Yes
Blinding: Open-label (not specified as blinded)
Sample Size: 90
Follow-up: 180 minutes (single-dose)
Centers: 1
Countries: Türkiye

Primary Outcome

Definition: Plasma dopamine concentration (ng/mL) at 0, 90, and 180 minutes after single-dose administration, measured by ELISA

Control	Intervention	HR/OR	P-value
LB: 66.4 (baseline) → 74.1 (90 min) → 80.8 (180 min) ng/mL	LCE: 76.7 (baseline) → 91.1 (90 min) → 90 (180 min) ng/mL	- (Reported as medians with IQR; no HR/CI calculated)	Between-group: .744 (baseline), .704 (90 min), .750 (180 min). Intragroup over time: LCE P=.355; LB P=.097

Limitations & Criticisms

Short observation window (180 minutes after a single dose) cannot capture steady-state pharmacodynamics or the longer half-life advantage of entacapone.
Only plasma dopamine was measured; no motor outcomes (UPDRS, ON/OFF time), quality-of-life, or adverse-event data captured.
ELISA-based dopamine measurement may cross-react with 3-O-methyldopa (3-OMD), which the authors did not exclude experimentally.
Single-center Turkish cohort restricted to early-stage (Hoehn & Yahr 1-1.5) unilateral PD limits generalizability to advanced PD or other populations.
Open-label single-dose design without blinding raises potential bias.
Baseline characteristics not stratified by treatment arm in the published tables, limiting assessment of randomization balance.
Modest sample size (n=90); abstract reports HPLC measurement while methods state ELISA — methodological inconsistency within the manuscript.

Citation

Medicine (Baltimore) 2026;105(21):e48895

View Original Publication →

LCE vs LB

Comparison of blood dopamine in Parkinson's patients treated with levodopa carbidopa entacapone vs levodopa benserazide: A randomized controlled trial

Bottom Line

Major Points

Design

Inclusion Criteria

Exclusion Criteria

Baseline Characteristics

Arms

Outcomes

Subgroup Analysis

Criticisms

Funding

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