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Efficacy and Safety of Carbidopa/Levodopa (CP-012B) in Participants with Parkinson’s Disease with Early Morning OFF Episodes

Verified siteInvestigational
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What is this trial about?

A plain-language summary of the goals, design and what participants do

The study focuses on people with Parkinson’s Disease who experience early morning OFF episodes, a condition where symptoms return upon waking before the first dose of medication. The investigational medicine, identified as CP-012B, is a prolonged‑release tablet that contains the two active ingredients carbidopa and levodopa. The purpose of the study is to determine whether CP-012B can increase the proportion of mornings that patients wake up in an ON state, meaning they feel better and have fewer symptoms, compared with a matching placebo.

Participants will be randomly assigned to receive either the study tablet or the placebo for about six weeks while continuing their regular daytime Parkinson’s medication. At the start of the study, each person will record their morning condition in an electronic diary for a week, then continue to do so each morning throughout the treatment period. After the treatment phase, a final visit will collect the diary information and a brief overall assessment of how the morning symptoms have changed.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Baseline Visit and Randomization

    You will attend a baseline visit on the first day of the study (Day 1). During this visit, your health status and current Parkinson’s disease treatment will be reviewed to confirm that your daytime medication regimen is stable.

    After the review, you will be randomly assigned to receive either CP-012B or a matching placebo. Neither you nor the study staff will know which product you receive.

  2. Step 2

    Start Study Medication

    You will begin taking the study medication each morning. If you are assigned to the test product, you will take one oral prolonged‑release tablet containing 250 mg of carbidopa and levodopa. The tablet is designed to release the medicine slowly over time.

    If you are assigned to the placebo, you will take one tablet that looks identical but does not contain active medicine.

    The medication is taken once daily for a total of six weeks, ending on Day 43.

  3. Step 3

    Daily Diary Recording

    Each morning, before taking your first dose of levodopa‑containing medication, you will use an electronic diary (eDiary) to record whether you wake up in an ON state (when symptoms are well controlled) or an OFF state (when symptoms return).

    You will continue this recording every day for the entire 6‑week treatment period. The data will be used to compare the proportion of mornings you are in an ON state at the start of the study and at the end of treatment.

  4. Step 4

    Safety Check Visits

    During the 6‑week period, you may be asked to attend brief safety check visits or phone calls. These visits are intended to monitor any side effects and to ensure the study medication is being taken as instructed.

    No additional medication adjustments are required unless instructed by the study team.

  5. Step 5

    End of Treatment Visit (Day 43)

    On Day 43, you will return for the end of treatment (EOT) visit. At this visit, the study staff will collect the final 7 days of eDiary data and evaluate the change in the proportion of mornings you woke up in an ON state compared with the baseline period.

    The staff will also ask you to complete a brief questionnaire about your overall impression of the morning symptoms.

  6. Step 6

    Study Completion

    After the EOT visit, you will stop taking the study medication. The study team will provide any necessary follow‑up instructions and will thank you for your participation.

Who can join the trial?

10 criteria

  • You must be at least 40 years old.
  • You must have a doctor‑confirmed diagnosis of Parkinson’s Disease that meets the official criteria from the Movement Disorder Society.
  • You must be taking a stable dose of carbidopa/levodopa (often written CD/LD) or benserazide/levodopa and not plan to change the dose during the study.
  • Your Parkinson’s symptoms must be rated by the study doctor as Hoehn and Yahr stage 1‑3 while you are in the “ON” state (the period when your medication is working).
  • You must show a clear response to levodopa therapy, as judged by the doctor.
  • In the week before screening you must have woken up in an “OFF” state (when medication has not yet started working) on at least 4 of the last 7 mornings.
  • In the same week you must have needed 30 minutes or more to reach the “ON” state on at least 4 of the 7 mornings, according to your diary.
  • Your other Parkinson’s medicines must stay the same throughout the trial, and certain drugs (entacapone, opicapone, and special slow‑release benserazide) cannot be used.
  • You must score at least 24 out of 30 on the Montreal Cognitive Assessment (MoCA) test, showing enough thinking ability to fill out the electronic diary (eDiary) on your own.
  • You must meet any additional requirements that are described in the study protocol.

Who cannot join the trial?

9 criteria

  • Having a type of Parkinson’s disease that is not the usual form (atypical) or that is caused by another condition (secondary parkinsonism).
  • Having a current or recurring illness that the doctor believes could affect safety or the ability to finish the study, such as severe dyskinesia (strong, involuntary movements), hepatic disorders (liver problems), renal insufficiency (kidney problems), congestive heart failure (weak heart that cannot pump blood well), conditions that change how the stomach empties food and absorbs medicine, or chronic wide‑angle glaucoma (a long‑lasting eye disease).
  • Having a serious or unstable mental health condition, including substance (drug or alcohol) abuse, dementia (memory loss), major depressive disorder (deep sadness), noticeable thinking problems (cognitive impairment), or drug‑induced psychosis (false beliefs or hallucinations caused by medication) that could make it hard to complete the electronic diary.
  • Having a sleep disorder or irregular sleep pattern that could interfere with measuring morning wake‑up, such as uncontrolled sleep apnea (breathing stops during sleep), severe insomnia (trouble sleeping), or irregular schedules like shift work.
  • Receiving advanced Parkinson’s treatments within the past 12 weeks, such as continuous medication delivered under the skin (subcutaneous LD infusion), through a tube to the stomach (enteral LD infusion), continuous apomorphine infusion, or having had deep brain stimulation surgery.
  • Receiving any medication delivered under the skin (subcutaneous) or under the tongue (sublingual) apomorphine, or inhaled levodopa (inhaled LD) within the past 4 weeks.
  • Using rescue medication for Parkinson’s disease during the night.
  • Being unable to reliably tell the difference between “ON” (medication working) and “OFF” (medication not working) motor states when waking up, or not understanding the study’s definitions of these states.
  • Any other reasons specified by the study protocol (other protocol‑defined criteria).
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Investigated drugs

CP-012B is a prolonged‑release tablet that contains a combination of two medicines, carbidopa and levodopa. These drugs are commonly used to treat Parkinson’s disease by helping the brain make more dopamine, a chemical that improves movement and reduces stiffness. In this study, the tablet is taken by mouth and is being tested to see if it can keep patients in an “ON” state (when symptoms are well controlled) when they first wake up in the morning.

What is already known about the treatment

CP-012B - It is taken by mouth as a prolonged‑release tablet that contains 250 mg of a combination of carbidopa and levodopa. The product is an established treatment for Parkinson’s disease and is widely described in medical literature. It is mainly used to reduce early‑morning “off” periods when patients feel stiff or slow after waking. The levodopa part changes into dopamine in the brain while carbidopa blocks its breakdown before it reaches the brain, helping to keep dopamine levels steadier; it belongs to the class of dopamine‑precursor drugs combined with a dopa‑decarboxylase inhibitor.

Investigated diseases

Parkinson disease with early morning OFF episodes - It is a chronic brain disorder caused by loss of dopamine‑producing cells, leading to tremor, stiffness, and slowed movement. In the early morning, patients often wake up with a return of these symptoms before taking medication, known as an OFF episode. These morning OFF periods can last from a few minutes to several hours and may interfere with daily activities. As the disease advances, motor fluctuations become more frequent and may affect other times of day. Non‑motor signs such as sleep problems and fatigue may also develop over time.
Trial detailsLast updated 7 Nov 2026
Age18+ yearsPhasePhase IITrial ID2026-526634-46-00Protocol codeCP-012-26001Estimated enrolment51 patientsSponsorContera Pharma A/S

sourced from the EU Clinical Trials Register and site verification

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