CLINICAL TRIALS PROFILE FOR CARBIDOPA; ENTACAPONE; LEVODOPA

505(b)(2) Clinical Trials for carbidopa; entacapone; levodopa

This table shows clinical trials for potential 505(b)(2) applications. See the next table for all clinical trials

Trial Type	Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
New Combination	NCT01766258 ↗	Efficacy and Safety Proof of Concept Study in Patients With Parkinson's Disease and End-of-dose Motor Fluctuations	Completed	Orion Corporation, Orion Pharma	Phase 2	2011-05-01	The primary objective of the study is to assess the efficacy, carbidopa dose response and safety of ODM-101, a new combination of levodopa, carbidopa and entacapone in the treatment of Parkinson's disease (PD) patients with end-of-dose motor fluctuations.

All Clinical Trials for carbidopa; entacapone; levodopa

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00099268 ↗	Efficacy and Safety of Carbidopa/Levodopa/Entacapone in Patients With Parkinson's Disease Requiring Initiation of Levodopa Therapy	Completed	Orion Corporation, Orion Pharma	Phase 3	2004-09-01	The CELC200A2401 study has been designed in order to evaluate the hypothesis that administering the combination carbidopa/levodopa/entacapone at the time that levodopa therapy is initiated results in a decrease in the risk of the development of motor complications for patients with Parkinson's disease.
NCT00099268 ↗	Efficacy and Safety of Carbidopa/Levodopa/Entacapone in Patients With Parkinson's Disease Requiring Initiation of Levodopa Therapy	Completed	Novartis Pharmaceuticals	Phase 3	2004-09-01	The CELC200A2401 study has been designed in order to evaluate the hypothesis that administering the combination carbidopa/levodopa/entacapone at the time that levodopa therapy is initiated results in a decrease in the risk of the development of motor complications for patients with Parkinson's disease.
NCT00134966 ↗	A Study to Evaluate Fixed Dose Carbidopa/Levodopa/Entacapone Versus Immediate Release Carbidopa/Levodopa	Completed	Novartis	Phase 3	2005-08-01	The purpose of this study is to achieve approval for the use of carbidopa/levodopa/entacapone in early Parkinson's disease (PD) by demonstrating that when used as initial levodopa therapy in early PD, carbidopa/levodopa/entacapone provides significantly greater symptomatic benefit than immediate release carbidopa/levodopa administered at the same levodopa dosage level of 100 mg three times a day (t.i.d.).
NCT00143026 ↗	Study to Compare the Effect of Treatment With Carbidopa/Levodopa/Entacapone on the Quality of Life of Patients With Parkinson's Disease. This Study is Not Recruiting in the United States	Completed	Novartis	Phase 4	2005-07-01	This study examines the effect of treatment of levodopa/entacapone on quality of life, as measured by the Parkinson's Disease-Questionnaire 8 (PDQ-8), in Parkinson's disease patients with no or minimal, non-disabling motor fluctuations.

Clinical Trial Conditions for carbidopa; entacapone; levodopa

Condition Name

Condition Name for carbidopa; entacapone; levodopa
Intervention	Trials
Parkinson's Disease	11
Healthy	5
Parkinson Disease	4
Parkinson's Disease With End of Dose Wearing Off	1

Condition MeSH

Condition MeSH for carbidopa; entacapone; levodopa
Intervention	Trials
Parkinson Disease	17
Disease	2
Cocaine-Related Disorders	2
Shy-Drager Syndrome	1

Clinical Trial Locations for carbidopa; entacapone; levodopa

Trials by Country

Trials by Country for carbidopa; entacapone; levodopa
Location	Trials
United States	72
Canada	11
Italy	11
Germany	6
Turkey	3

Trials by US State

Trials by US State for carbidopa; entacapone; levodopa
Location	Trials
New York	6
Florida	5
California	5
Arizona	4
Texas	4

Clinical Trial Progress for carbidopa; entacapone; levodopa

Clinical Trial Phase

Clinical Trial Phase for carbidopa; entacapone; levodopa
Clinical Trial Phase	Trials
PHASE4	1
Phase 4	5
Phase 3	3

Clinical Trial Status

Clinical Trial Status for carbidopa; entacapone; levodopa
Clinical Trial Phase	Trials
Completed	18
Terminated	2
Unknown status	1

Clinical Trial Sponsors for carbidopa; entacapone; levodopa

Sponsor Name

Sponsor Name for carbidopa; entacapone; levodopa
Sponsor	Trials
Novartis	8
Orion Corporation, Orion Pharma	3
Novartis Pharmaceuticals	3

Sponsor Type

Sponsor Type for carbidopa; entacapone; levodopa
Sponsor	Trials
Industry	20
Other	8
NIH	2

CARBIDOPA; ENTACAPONE; LEVODOPA (Dopamine Replacement + COMT Inhibition): Clinical Trials Update, Market Analysis and Projections

Last updated: April 29, 2026

What is the current clinical development picture for carbidopa/entacapone/levodopa?

Core product context

Carbidopa/levodopa combinations are standard-of-care for Parkinson’s disease (PD). Entacapone is a catechol-O-methyltransferase (COMT) inhibitor that extends levodopa exposure. The three-drug combination is used in a “levodopa + carbidopa + COMT inhibitor” regimen across multiple geographies and formulations (including combination products where available).

Clinical-trial update: where late-stage activity tends to concentrate

Recent trial activity for PD combination regimens generally clusters around:

• Motor symptom control and “on/off” states using levodopa-based architectures
• Time-in-therapeutic window as the primary efficacy metric
• Cardiovascular, neuropsychiatric, and dyskinesia safety endpoints, consistent with COMT inhibitor risk profiles

However, no complete and reliable, product-specific late-stage trial register snapshot can be produced from the information available in this chat. Without named identifiers (trial registry IDs), recruitment statuses, endpoints, or sponsor details tied specifically to the carbidopa/entacapone/levodopa combination, a definitive “clinical trials update” cannot be authored without risking factual errors.

How do you underwrite market demand for carbidopa/entacapone/levodopa?

Market demand drivers

• PD prevalence and treated population: PD incidence and prevalence increase with age; levodopa-based therapy anchors long-term treatment pathways.
• Treatment persistence and regimen optimization: Entacapone is typically used to smooth levodopa pharmacokinetics and improve motor outcomes in patients who have wearing-off.
• Genericization and payer behavior: Carbidopa/levodopa and entacapone have high generic penetration in many markets, which typically compresses price and shifts value growth to volume and geographic expansion.

Market constraints that cap growth

• Competing PD mechanisms: Catechol-O-methyltransferase inhibition faces competition from other add-ons and in-class maintenance strategies (including newer device-aided and oral levodopa adjuncts).
• Efficacy saturation in advanced disease: Late-stage PD often uses multi-mechanism strategies, reducing incremental value of any single adjunct once patients progress.
• Safety and tolerability: COMT inhibition contributes to diarrhea risk and can affect adherence, which impacts effective market volume.

What is the market size and projection for this drug combination?

A quantified market analysis and forward projection require defensible inputs (current sales by region, patent and exclusivity position, price and volume assumptions, and pipeline substitution dynamics). The prompt provides none of these, and no reliable numeric market base or forecast inputs are available in this chat. Producing numbers would introduce material factual risk.

Accordingly, no market sizing or projection figures are provided here.

What competitive landscape impacts substitution risk?

Direct competitive class dynamics

Carbidopa/levodopa + COMT inhibition competes with:

• Other levodopa add-ons that address wearing-off (different mechanisms, similar clinical goal)
• Device-aided approaches and advanced delivery systems
• New oral architectures aiming to improve “on” time with reduced fluctuations

Expected substitution pattern

• Patients stable on a levodopa/entacapone regimen tend to persist unless:
  • tolerability declines,
  • payer rules change,
  • or a superior add-on becomes accessible at lower net cost.
• Competitive pressure tends to express as net price erosion more than absolute volume collapse, given persistent need for levodopa-based therapy.

Commercial implications for R&D and investment

Where value usually concentrates

• Line extensions that improve dosing convenience, reduce adverse effects, or improve time-in-therapeutic window can defend market share even when generics dominate.
• Formulation differentiation (release profile, dosing schedule adherence) can matter more than new MOA in mature PD spaces.

Where development risk is highest

• Demonstrating meaningful superiority over established levodopa+COMT inhibition requires strong clinical endpoints and careful comparator selection.
• Regulatory and payer scrutiny focuses on clinically interpretable endpoints (on-time, off-time, dyskinesia burden) and safety.

Key Takeaways

• Carbidopa/levodopa + entacapone is an established PD regimen aligned with levodopa wearing-off management.
• A specific, product-precise clinical trials update cannot be substantiated from the information available here without trial identifiers and status data.
• Market sizing and numeric projections cannot be produced without current sales baselines and forecast inputs; qualitative drivers indicate price compression risk and competitive substitution mainly through net cost dynamics rather than complete therapeutic displacement.

FAQs

1. Is carbidopa/entacapone/levodopa still used in current PD treatment algorithms?
   Yes. COMT inhibition remains a standard adjunct to levodopa-based therapy for wearing-off in appropriate patients.

2. What endpoints typically matter most in trials for levodopa add-ons?
   Time in on-state, time in off-state, “wearing-off” frequency, and dyskinesia or motor complications, with safety monitoring for known COMT inhibitor effects.

3. Does generic penetration cap market growth?
   Yes in most markets; it typically drives net sales growth to rely on volume, patient pool expansion, and differentiated formulation or access strategies.

4. Which competitive mechanisms most affect this regimen?
   Other wearing-off add-ons and advanced delivery approaches that improve on-time or reduce fluctuations.

5. What would create a meaningful market shift for this combination?
   A differentiated formulation that improves tolerability or on-time, or payer access changes that materially alter net cost versus alternatives.

References (APA)

[1] European Medicines Agency. (n.d.). Entacapone: EPAR product information. European Union. https://www.ema.europa.eu/
[2] U.S. Food and Drug Administration. (n.d.). Entacapone and levodopa combination product labeling and review information. FDA. https://www.fda.gov/
[3] Parkinson’s Foundation. (n.d.). Parkinson’s disease treatment overview. Parkinson’s Foundation. https://www.parkinson.org/