Last Updated: May 10, 2026

CLINICAL TRIALS PROFILE FOR SINEMET CR


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505(b)(2) Clinical Trials for SINEMET CR

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 Formulation NCT00363727 ↗ Onset Motor Complications Using REQUIP CR (Ropinirole Controlled-release) As Add-on Therapy To L-dopa In Parkinson's Completed GlaxoSmithKline Phase 3 2003-12-01 This study evaluates how effective a new formulation of a marketed drug is in increasing the time to onset of dyskinesia (abnormal twisting, writhing movements) in patients with Parkinson's Disease who have been taking levodopa for less than 2 years.
>Trial Type >Trial ID >Title >Status >Phase >Start Date >Summary

All Clinical Trials for SINEMET CR

Trial ID Title Status Sponsor Phase Start Date Summary
NCT00004576 ↗ Study of LY300164 for the Treatment of Parkinson's Disease Completed National Institute of Neurological Disorders and Stroke (NINDS) Phase 2 2000-02-01 This study will test the effectiveness of an experimental drug called LY300164 on improving Parkinson's disease symptoms, such as movement impairments and tremor, as well as involuntary movements produced by long-term treatment with levodopa. Patients with relatively advanced (Stage II to IV) Parkinson's disease between 30 and 75 years of age may be eligible for this 8-week study. Participants will have a complete medical history and physical examination, including blood tests and an electrocardiogram, and possibly brain magnetic resonance imaging (MRI), CT scan, and chest X-ray. Patients will stop taking all anti-parkinsonism medications except levodopa (Sinemet) and the experimental drug during the study. For the first 1 to 3 days, patients will be in the hospital for a levodopa "dose-finding" procedure. For this study, levodopa is infused through a vein for up to 8 hours, with symptoms monitored frequently to determine the doses that will produce two results: 1) the dose that is less than what is needed to relieve symptoms, and 2) the dose that relieves symptoms, but may produce dyskinesias. When these dose rates are determined, patients will begin treatment in one of two groups. One will take LY300164 3 times a day, along with levodopa, for 3 weeks. The second group will take placebo tablets (a look-alike tablet with no active ingredient) and levodopa on the same schedule as the LY300164 group. A brief medical examination and routine blood and urine tests will be done weekly. The drug dose will be increased every 3 to 4 days until significant side effects occur or the maximal dose is reached. Patients will be closely monitored for 4 hours after every increase. At the end of the 3 weeks, or when the maximal dose is reached, patients will be readmitted to the hospital for 2 to 3 days for a second levodopa dose-finding study, while continuing on LY300164 or placebo. After this test, patients will resume taking levodopa and the experimental drug or placebo as before for another 2 weeks. At the end of the 2-weeks, the entire procedure will be repeated in both groups, but the treatments will be switched-that is, the patients who were taking LY300164 will now take placebo, and the patients who took placebo will now take the drug. At the end of the second 3 weeks, the levodopa infusion procedure will be repeated once more. Throughout the study, parkinsonism symptoms and dyskinesias will be evaluated and blood samples will be drawn periodically to measure drug levels.
NCT00004733 ↗ Timing of Levodopa Treatment in Parkinson's Disease Completed National Institute of Neurological Disorders and Stroke (NINDS) Phase 3 1998-01-01 The ELLDOPA study is a controlled clinical trial in patients with newly diagnosed PD to determine the optimal timing and dosing with levodopa (Sinemet or its generic equivalents).
NCT00006077 ↗ Effects of Monoamine Reuptake Inhibitor NS2330 in Parkinson's Disease Completed National Institute of Neurological Disorders and Stroke (NINDS) Phase 2 2000-08-01 This study will evaluate the effects of an experimental drug called NS2330 on Parkinson's disease symptoms and on dyskinesias (involuntary movements) that develop as a result of long-term treatment with levodopa. This drug prevents the neurotransmitter dopamine from entering nerve cells. Patients between 18 and 75 years old who have moderately advanced Parkinson's disease and motor problems resulting from levodopa therapy may be eligible for this 5-week study. Candidates will have a complete medical history and physical examination with a detailed neurological evaluation. If needed, some patients will undergo a magnetic resonance imaging (MRI) or computerized tomography (CT) scan of the brain and a chest X-ray. All patients will have blood and urine tests and an electrocardiogram (EKG) and will take a written test for evaluation of depression. Patients enrolled in the study will, if possible, stop taking all antiparkinson medications except levodopa (Sinemet) for one month before the study begins and through its duration. For the first 1 to 3 days, patients will undergo a levodopa "dose-finding" procedure. For this study, patients will stop taking their usual oral levodopa medicine and instead will have levodopa infused through a vein for up to 12 hours. During the infusions, the drug dose will be increased slowly until either 1) parkinsonism symptoms improve, 2) dyskinesias appear, 3) unacceptable side effects occur, or 4) the maximum study dose is reached. When the patient's optimal dose is determined, treatment will begin. Patients will take three pills containing NS2330 or placebo (a look-alike pill with no active ingredient) 3 days a week for up to 5 weeks, in addition to their regular levodopa medication. All participants will receive placebo at some point in the study; some patients will receive only placebo throughout the entire 5 weeks. On treatment days, patients will have a brief medical examination before receiving the drug and will then be monitored for side effects for about 6 to 8 hours after taking the drug. At the beginning of weeks 2 and 5, the levodopa infusions will be repeated at the previously determined optimum rate. Throughout the study, parkinsonism symptoms, dyskinesias and depression will be evaluated. Blood and urine samples will be collected each week for standard safety tests, and blood will also be drawn periodically to measure NS2330 levels.
NCT00006337 ↗ KW-6002 to Treat Parkinson's Disease Completed National Institute of Neurological Disorders and Stroke (NINDS) Phase 2 2000-10-01 This study will evaluate the effects of an experimental drug called KW-6002 on Parkinson's disease symptoms and on dyskinesias (involuntary movements) that develop as a result of long-term treatment with levodopa. This drug blocks the action of the neurotransmitter adenosine, thought to be involved in producing Parkinson's symptoms. Patients with relatively advanced (Stage II to IV) Parkinson's disease between 30 and 80 years of age may be eligible for this 7-week study. Participants will have a complete medical history and physical examination, including blood tests and an electrocardiogram, and possibly brain magnetic resonance imaging (MRI), CT scan, and chest X-ray. Patients enrolled in the study will, if possible, stop taking all antiparkinsonian medications except levodopa (Sinemet) for one month before the study begins and throughout its duration. For the first 1 to 3 days, patients will be admitted to the NIH Clinical center to undergo a levodopa "dose-finding" procedure. For this study, patients will stop taking Sinemet and instead will have levodopa infused through a vein for up to 8 hours/day. During the infusions, the drug dose will be increased slowly until either 1) parkinsonian symptoms improve, 2) unacceptable side effects occur, or 3) the maximum study dose is reached. Symptoms will be monitored frequently to find two infusion rates: 1) one that is less than what is needed to relieve symptoms, and 2) one that relieves symptoms but may produce dyskinesias. This procedure will be repeated at the end of weeks 2, 4 and 6 of the study. When the patient's optimal dose is determined treatment will begin. Patients will take tablets or capsules containing KW-6002 or placebo (a look-alike pill with no active ingredient) once a day for 2 weeks, in addition to their regular Sinemet. All participants will receive placebo at least 2 weeks during the study; some patients will receive only placebo throughout the entire 7 weeks. At the end of weeks 1, 3 and 5, patients will be evaluated with a brief physical examination, routine blood and urine tests, and assessment of any adverse effects. Throughout the study, parkinsonian symptoms and dyskinesias will be evaluated and blood samples will be drawn periodically to measure drug levels.
>Trial ID >Title >Status >Phase >Start Date >Summary

Clinical Trial Conditions for SINEMET CR

Condition Name

Condition Name for SINEMET CR
Intervention Trials
Parkinson's Disease 32
Parkinson Disease 18
Dyskinesias 5
Depression 5
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Condition MeSH

Condition MeSH for SINEMET CR
Intervention Trials
Parkinson Disease 55
Dyskinesias 6
Stroke 4
Depression 4
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Clinical Trial Locations for SINEMET CR

Trials by Country

Trials by Country for SINEMET CR
Location Trials
United States 154
Canada 8
Italy 6
Finland 6
Spain 6
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Trials by US State

Trials by US State for SINEMET CR
Location Trials
Maryland 12
California 11
Illinois 10
Georgia 10
Texas 10
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Clinical Trial Progress for SINEMET CR

Clinical Trial Phase

Clinical Trial Phase for SINEMET CR
Clinical Trial Phase Trials
PHASE1 2
Phase 4 12
Phase 3 5
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Clinical Trial Status

Clinical Trial Status for SINEMET CR
Clinical Trial Phase Trials
Completed 62
Recruiting 10
Terminated 4
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Clinical Trial Sponsors for SINEMET CR

Sponsor Name

Sponsor Name for SINEMET CR
Sponsor Trials
National Institute of Neurological Disorders and Stroke (NINDS) 13
Bial - Portela C S.A. 7
Orion Corporation, Orion Pharma 7
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Sponsor Type

Sponsor Type for SINEMET CR
Sponsor Trials
Other 64
Industry 46
NIH 28
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Sinemet CR (Carbidopa/Levodopa Controlled-Release): Clinical Trials Update, Market Analysis, and Projection

Last updated: May 6, 2026

What is Sinemet CR and what is its clinical positioning?

Sinemet CR is a controlled-release oral formulation of carbidopa/levodopa indicated for Parkinson’s disease (and related parkinsonian syndromes). It is a long-standing, branded product in the levodopa/carbidopa category; clinical evidence is dominated by historical efficacy and safety compared with standard carbidopa/levodopa and by formulation-specific data on “on” time, motor fluctuations, and nocturnal symptoms.

Are there active or materially new clinical trials for Sinemet CR?

No sufficient public, trial-registration-level evidence is available in the provided dataset to support a definitive “active trials” status, sponsor-level updates, or recent protocol readouts for Sinemet CR specifically.

What does the last established efficacy and safety evidence base look like?

Sinemet CR’s clinical profile is anchored in controlled-release pharmacokinetics intended to reduce peak-trough variation and smooth dopamine replacement. The clinical endpoints historically used for levodopa controlled-release products include:

  • Motor symptom control (UPDRS-related outcomes in trials, where used)
  • Reduction in “off” time and fewer end-of-dose wearing off episodes
  • Improved continuity of benefit through the day and overnight
  • Safety and tolerability typical of levodopa therapy, including dyskinesia and neuropsychiatric effects, and adverse events attributable to dopaminergic signaling

How does Sinemet CR fit into the competitive landscape?

Sinemet CR competes in the oral levodopa backbone segment of Parkinson’s disease treatment. Its practical competition comes from:

  • Immediate-release carbidopa/levodopa tablets
  • Other extended-release carbidopa/levodopa formulations
  • Adjunctive dopaminergic therapies that reduce levodopa requirement or target motor fluctuations (COMT inhibitors, MAO-B inhibitors, dopamine agonists)
  • Device-aided and infusion therapies (advanced PD segment), which siphon later-line patients

Because Sinemet CR is a controlled-release branded product with mature usage, “clinical trial catalysts” are not the main driver of incremental growth. Market dynamics are primarily shaped by formularies, prescriber switching behavior, availability of alternatives, and payer preference.


What is the current market size and growth outlook for oral levodopa/carbidopa (category view)?

A rigorous, Sinemet CR-specific revenue market model cannot be produced from the provided dataset. However, a credible category projection framework for Parkinson’s disease oral levodopa therapies can be built on standard industry drivers:

  • Parkinson’s disease incidence and prevalence growth (aging demographics)
  • Treatment persistence (levodopa is long-term)
  • Intensification of therapy with disease progression (more patients require combination treatment)
  • Shift among formulations to manage motor fluctuations

Category growth generally tracks the broader Parkinson’s market, tempered by:

  • Generic penetration in carbidopa/levodopa immediate-release
  • Competitive pressure from newer extended-release and adjunct agents
  • Payer step edits and prior authorization design

How should investors and R&D teams project Sinemet CR performance?

Given the absence of newly evidenced active trials in the provided dataset, Sinemet CR projections should be built on structural market drivers rather than near-term clinical catalysts:

  1. Share retention and conversion within the levodopa backbone
    • Growth comes from switching from immediate-release to controlled-release in patients with wearing-off or nighttime symptoms.
  2. Payer and formulary governance
    • Coverage decisions and copayment tiers influence persistence and adherence.
  3. Generic reference pricing dynamics
    • Even if Sinemet CR retains differentiated positioning, payer pricing pressure can reduce net revenue per patient over time.
  4. Lifecycle effects
    • Mature brands typically face slower unit growth and more reliance on patient-level conversion and dose stability.

Projection method (model-ready structure):

  • Total addressable Parkinson’s treated population (annual)
  • Share on levodopa-containing regimens
  • Controlled-release share within levodopa regimens
  • Sinemet CR share within controlled-release (branded vs other controlled-release options)
  • Net revenue per prescription adjusted for rebates, copay, and contracting
  • Attrition and persistence by progression and adverse events
  • Price erosion curve under generic and payer pressure

Because the required input numeric assumptions (category revenue, controlled-release share, branded share, pricing erosion) are not present in the supplied dataset, a fully quantified Sinemet CR forecast cannot be produced to a standard acceptable for investment decision-making.


What patent and exclusivity events could influence future demand?

No patent-expiration or exclusivity event data for Sinemet CR is included in the provided dataset, so an evidence-based timetable for market exclusivity is not supportable here.


Scenario framework: what are the key variables that can move Sinemet CR outcomes?

Even without producing a numeric forecast, Sinemet CR outcomes hinge on a small set of measurable variables:

  • Controlled-release penetration rate in treated PD populations
  • Branded differentiation vs alternatives (formulation-specific tolerability, dosing convenience, prescriber preference)
  • Payer reimbursement design (preferred status, step edits, and prior authorization frequency)
  • Utilization shift to advanced therapies (infusions, device-aided strategies) in later-line patients
  • Adverse event management (dyskinesia and psychiatric AEs influence adherence and switching)

Key Takeaways

  • Sinemet CR is a mature, branded controlled-release carbidopa/levodopa option for Parkinson’s disease, positioned around smoother dopaminergic delivery to address motor fluctuations.
  • The provided dataset does not contain sufficient public trial-registration evidence to establish an up-to-date “active clinical trials” status or recent readouts specifically for Sinemet CR.
  • A precise Sinemet CR market forecast cannot be quantified from the provided dataset; the correct projection approach relies on category-level PD prevalence growth, controlled-release penetration, branded share, and net price erosion under payer and generic pressure.
  • Near-term performance is expected to be driven more by formulary dynamics and substitution behavior than by new clinical catalysts, absent evidence of recent trial breakthroughs.

FAQs

1) Is Sinemet CR still being studied in new clinical trials?
The provided dataset does not include sufficient trial-registration-level evidence to confirm current or recent active Sinemet CR studies.

2) What clinical endpoints matter most for controlled-release levodopa brands?
Motor fluctuations, especially “off” time reduction and maintenance of “on” periods, with tolerability outcomes typical of levodopa therapy.

3) What drives Sinemet CR demand in practice?
Switching from immediate-release to controlled-release in patients with wearing-off and nocturnal symptoms, moderated by payer coverage and net price.

4) How does generic competition affect Sinemet CR?
Generic and payer pricing pressure typically compress net revenue per prescription, even if differentiation supports some persistence and conversion.

5) What is the right unit for projecting Sinemet CR?
Patients on levodopa regimens, the subset using controlled-release, Sinemet CR share among controlled-release options, then adjusted by persistence and net price.


References

[1] FDA. Sinemet CR (carbidopa and levodopa) Prescribing Information. U.S. Food and Drug Administration. (Accessed via provided sources, if any).

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