A Study to Assess Effect of Dosing Intervals on Multiple-Dose Pharmacokinetics of WD-1603 Taken Before Meals in Healthy Participants

NCT07442591 | Recruiting Phase 1 FDA Drug

• 2 other identifiers: WD-1603-1010CTR20260505
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

WD-1603 contains two different drugs called levodopa and carbidopa in one tablet. The goal of this clinical trial is to see if taking the study drug WD-1603 at different time intervals affects how the drug acts in healthy volunteers. We also want to learn about the safety of WD-1603. The main question we want to answer is:

• How does the body process WD-1603 when it is taken by different time intervals? What will participants do?
• Participants will take one tablet of WD-1603 twice a day on three separate days.
• On each dosing day, the two doses will be spaced different hours apart.
• Between each dosing day, there will be a rest period of up to 7 days.

Conditions

Healhty

Keywords

multiple-dose, open-label, pharmacokinetic

Outcome Measures

Primary Outcomes (11)

• Maximal Plasma Concentration (Cmax) of Carbidopa and Levodopa

  Maximal plasma concentration (Cmax) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.

  24 hours after the first dose.

• Area under the Concentration versus Time Curve from 0 to Time t (AUC0-t) of Carbidopa and Levodopa

  Area under the concentration versus time curve from 0 to time t (AUC0-t) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.

  24 hours after the first dose.

• Area under the Concentration versus Time Curve from 0 Extrapolated to Infinity (AUC0-∞) of Carbidopa and Levodopa

  Area under the concentration versus time curve from 0 extrapolated to infinity (AUC0-∞) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.

  24 hours after the first dose.

• Time to Maximal Plasma Concentration (tmax) of Carbidopa and Levodopa

  Time to maximal plasma concentration (tmax) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.

  24 hours after the first dose.

• Elimination Half-life (t1/2) of Carbidopa and Levodopa

  Elimination half-life (t1/2) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.

  24 hours after the first dose.

• Terminal Elimination Rate Constant (λz) of Carbidopa and Levodopa

  Terminal elimination rate constant (λz) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.

  24 hours after the first dose.

• Apparent Clearance (CL/F) of Carbidopa and Levodopa

  Apparent clearance (CL/F) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.

  24 hours after the first dose.

• Apparent Volume of Distribution (Vd/F) of Carbidopa and Levodopa

  Apparent volume of distribution (Vd/F) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.

  24 hours after the first dose.

• Cmax of Levodopa and Carbidopa for Each Dose

  Cmax of carbidopa and levodopa for each dose after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.

  24 hours after the first dose.

• AUC0-τ of Levodopa and Carbidopa for Each Dose

  AUC0-τ of carbidopa and levodopa for each dose after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants, where τ is the dosing interval.

  24 hours after the first dose.

• Ratio of ΔC0.5 between the Two Doses

  Ratio of ΔC0.5 of carbidopa and levodopa between the two doses after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants, where the ΔC0.5 of the first dose is equal to the concetration at 0.5 hour C0.5; the ΔC0.5 of the second dose is the difference between the concontration at t+0.5 hours (Ct+0.5) and the concentration at t (Ct) (t is the dosing interval).

  24 hours after the first dose.

Secondary Outcomes (2)

• Number and Percentage of Participants for Each Type of Adverse Events (AEs)

  Throughout the study, about 21 days.

• Number and Percentage of Participants with Abnormal Findings in Laboratory Tests, Physical Examinations, Vital Signs and 12-lead Electrocardiogram (12-lead ECG)

  Baseline, 1 week, 2 weeks and 3 weeks.

Study Arms (3)

WD-1603 (25 mg/150 mg) 5-hour interval

EXPERIMENTAL

Cohort 1: Participants will take one WD-1603 25 mg/150 mg tablet orally 5 minutes before each meal, twice daily with a 5-hour interval between doses, over a 1-day dosing period.

Drug: Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)

WD-1603 (25 mg/150 mg) 6-hour interval

EXPERIMENTAL

Cohort 2: Participants will take one WD-1603 25 mg/150 mg tablet orally 5 minutes before each meal, twice daily with a 6-hour interval between doses, over a 1-day dosing period.

Drug: Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)

WD-1603 (25 mg/150 mg) 7-hour interval

EXPERIMENTAL

Cohort 3: Participants will take one WD-1603 25 mg/150 mg tablet orally 5 minutes before each meal, twice daily with a 7-hour interval between doses, over a 1-day dosing period.

Drug: Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)

Interventions

Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg) DRUG

Administered twice daily for one day with a 5-hour interval between doses.

WD-1603 (25 mg/150 mg) 5-hour interval

Eligibility Criteria

• Age: 18 Years - 55 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy adult male or female participants aged 18 to 55 years (inclusive) at the time of signing the informed consent form (ICF).
• Body weight: male ≥ 50 kg, female ≥ 45 kg; body mass index (BMI) between 18 and 27 kg/m² (inclusive) (BMI = weight \[kg\] / height² \[m²\]).
• Medical history inquiry, physical examination, vital signs, laboratory tests (complete blood count, urinalysis, blood biochemistry, serological virology tests, coagulation function), 12-lead ECG, intraocular pressure measurement, abdominal ultrasound, and chest X-ray during the screening period are all within normal ranges or clinically insignificant if outside normal ranges.
• Participants (including their spouses or partners) have no plans for conception or for donating sperm/eggs from the time of signing the ICF (for females)/first dosing (for males) until 3 months after the last dose, and voluntarily agree to use effective non-pharmacological contraception during the trial period.
• Fully understand the trial content, procedures, and potential adverse reactions, voluntarily agree to participate, and sign the ICF before any trial-related procedures begin.
• Able to communicate well with the investigators and capable of understanding and complying with the requirements of this trial.

You may not qualify if:

• Allergy-prone constitution, history of allergic diseases, or known severe allergic reaction or allergy history to levodopa/carbidopa or related medications.
• Drug use within 3 months prior to screening, history of drug abuse, or positive urine drug abuse screening (morphine, methamphetamine, ketamine, methylenedioxymethamphetamine, tetrahydrocannabinol acid, cocaine).
• History of glaucoma, cancer, diabetes mellitus, bronchial asthma, or any clinically significant cardiovascular, respiratory, metabolic, renal, hepatic, gastrointestinal, hematological, dermatological, endocrine, neuropsychiatric diseases, or other significant conditions.
• Dysphagia or any condition that may affect drug absorption (e.g., gastrectomy, cholecystectomy, gastric bypass, duodenotomy, colectomy), or gastrointestinal diseases causing clinically significant symptoms such as nausea, vomiting, diarrhea, or malabsorption syndrome.
• History of orthostatic hypotension.
• Any relevant medical history, surgical history, or trauma within 3 months prior to the first dose that may affect trial safety or drug pharmacokinetics, or planned surgery during the trial period.
• Use of prescription drugs, over-the-counter medications, health products, Chinese herbal medicines, or dietary supplements within 4 weeks prior to the first dose, especially monoamine oxidase inhibitors (e.g., phenelzine, rasagiline, selegiline, brofaromine, toloxatone, isocarboxazid, etc.).
• Participation in any clinical trial and receipt of investigational drugs within 3 months prior to the first dose.
• Blood donation (including component blood) or significant blood loss (≥400 mL), blood transfusion, or use of blood products within 3 months prior to the first dose.
• Difficulty with venous access, unsuitability or unwillingness to use intravenous catheters, or history of needle/blood phobia.
• Heavy smokers or average daily cigarette consumption of more than 10 cigarettes within 3 months prior to screening.
• Alcohol consumption exceeding 21 standard units per week within 3 months prior to screening (1 standard unit contains 14g of alcohol, e.g., 360 mL of beer, 45 mL of 40% spirits, or 150 mL of wine), positive alcohol breath test, or unwillingness to abstain from alcohol from 48 hours before the first dose of each period until the completion of blood sampling for that period.
• Estimated glomerular filtration rate (eGFR) \< 90 mL/min·1.73m² during the screening period.
• During screening: systolic blood pressure \< 90 mmHg or ≥ 140 mmHg, diastolic blood pressure \< 60 mmHg or ≥ 90 mmHg, pulse rate \> 100 beats/min or \< 50 beats/min.
• History of prolonged QT interval or other clinically significant cardiac diseases, or QTcF ≥ 450 ms on ECG during screening.

Sponsors & Collaborators

• Shanghai WD Pharmaceutical Co., Ltd.: lead
• Shanghai Xuhui Central Hospital: collaborator
• BalGenSource Medical Technology Co. Ltd.: collaborator
• Shanghai Xihua Scientific Co., Ltd.: collaborator
• Shanghai BioGuider Medical Technology Co., Ltd.: collaborator

Study Sites (1)

Shanghai Xuhui Central Hospital

Shanghai, China

RECRUITING

Related Publications (5)

• 中华医学会神经病学分会帕金森病及运动障碍学组 and 中国医师协会神经内科医师分会帕金森病及运动障碍学组, 中国帕金森病治疗指南（第四版）. 中华神经科杂志, 2020. 53(12): p. 973-986.

  BACKGROUND

• Kempster PA, Frankel JP, Bovingdon M, Webster R, Lees AJ, Stern GM. Levodopa peripheral pharmacokinetics and duration of motor response in Parkinson's disease. J Neurol Neurosurg Psychiatry. 1989 Jun;52(6):718-23. doi: 10.1136/jnnp.52.6.718.

  PMID: 2501456 BACKGROUND

• Adepu S, Ramakrishna S. Controlled Drug Delivery Systems: Current Status and Future Directions. Molecules. 2021 Sep 29;26(19):5905. doi: 10.3390/molecules26195905.

  PMID: 34641447 BACKGROUND

• Buril J, Burilova P, Pokorna A, Kovacova I, Balaz M. Representation of Parkinson's disease and atypical Parkinson's syndromes in the Czech Republic-A nationwide retrospective study. PLoS One. 2021 Feb 2;16(2):e0246342. doi: 10.1371/journal.pone.0246342. eCollection 2021.

  PMID: 33529251 BACKGROUND

• Tysnes OB, Storstein A. Epidemiology of Parkinson's disease. J Neural Transm (Vienna). 2017 Aug;124(8):901-905. doi: 10.1007/s00702-017-1686-y. Epub 2017 Feb 1.

  PMID: 28150045 BACKGROUND

Related Links

• SINEMET CR \[package insert\].

MeSH Terms

Interventions

Carbidopa

Intervention Hierarchy (Ancestors)

Methyldopa; Dihydroxyphenylalanine; Catecholamines; Amines; Organic Chemicals; Hydrazines; Catechols; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons

Study Officials

• Yanmei Liu, Master

  Shanghai Xuhui Central Hospital

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Danyong Zhang, Master

CONTACT

+86-138-1672-0823; danyong.zhang@wdpharma.com

Yan Jiao, Master

CONTACT

+86-180-1937-4596; yan.jiao@wdpharma.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SEQUENTIAL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: February 12, 2026
• First Posted: March 2, 2026
• Study Start: March 24, 2026
• Primary Completion: June 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: April 8, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)