A Study of the Efficacy and Safety of Carbidopa-Levodopa Extended-Release Tablets in Patients With Parkinson's Disease

To compare the changes from the baseline mean value before the study to the mean value on the 27th day of the study of the sum of MDS-Unified Parkinson's Disease Rating Scale-Part II (MDS-UPDRS-II) and MDS-Unified Parkinson's Disease Rating Scale-Part III (MDS-UPDRS-III) between each dose group and the placebo group. MDS-UPDRS-II is Motor Experiences of Daily Living, and MDS-UPDRS-III is Motor Examination. Each item is rated on a 5-point Likert-type scale (0-4), with higher scores suggesting more severe impairment.

To compare the changes from the baseline mean value before the study to the mean value on the 14th day of the study of the sum of MDS-Unified Parkinson's Disease Rating Scale-Part II (MDS-UPDRS-II) and MDS-Unified Parkinson's Disease Rating Scale-Part III (MDS-UPDRS-III) between each dose group and the placebo group. MDS-UPDRS-II is Motor Experiences of Daily Living, and MDS-UPDRS-III is Motor Examination. Each item is rated on a 5-point Likert-type scale (0-4), with higher scores suggesting more severe impairment.

Complete the MDS-Unified Parkinson's Disease Rating Scale-Part II (MDS-UPDRS-II) assessment on the morning of each visiting period.

During the screening period, an outpatient evaluation is performed before administration. In the other visit periods, 6 assessments of the MDS-Unified Parkinson's Disease Rating Scale-Part III (MDS-UPDRS-III) are carried out at the time point of the clinical trial administration.

To evaluate Cmax (Maximum Plasma Concentration) of the pharmacokinetics of WD-1603 on the 28th day.

To evaluate Cmin (Minimum Plasma Concentration) of the pharmacokinetics of WD-1603 on the 28th day.

To evaluate the AUC (Area under the plasma concentration versus time curve) of the pharmacokinetics of WD-1603 on the 28th day.

To evaluate levodopa blood concentration fluctuation index of WD-1603 on the 28th day.

Plasma levodopa is summarized according to the blood sampling time point of the protocol; describe and compare the mean of the blood concentration of levodopa and carbidopa in each dose group, and calculate the fluctuation index ([Cmax-Cmin]/Cavg, Cavg= AUC0-t/t), where Cmax is Maximum Plasma Concentration, Cmin is Minimum Plasma Concentration, Cave is Average Plasma Concentration, AUC0-t is Area under the Plasma Concentration versus Time Curve Calculated from 0 to the Last Measurable Observation.

AEs refer to all adverse medical events in clinical research subjects, which can be manifested as symptoms and signs, diseases, or abnormal laboratory tests, but they may not have a causal relationship with the study drug. The following must be recorded as AE when at least one of the following criteria is met: 1. Accompanying symptoms and signs; 2. The results of the examination require treatment measures (such as surgical intervention); 3. The result of the inspection leads to changes in the dosing schedule of the study drug (such as dose change, dosing delay, discontinuation) of the study. The following can be referred to do AE severity classification. 1 (Mild): Asymptomatic or mild; only clinically seen; 2(Moderate): Requires minor, or non-invasive treatment; 3 (Severe): Severe or medically significant but not immediately life-threatening; 4 (Life-threatening): Urgent treatment is needed; 5 (Death): Death related to adverse events.

BDI-II scores are collected for safety assessment. BDI-II is a 21-item self-administered survey which is scored on a scale of 0-3 in a list of four statements arranged in increasing severity about a particular symptom of depression. Total score of 0-13 is considered minimal range, 14-19 is mild, 20-28 is moderate, and 29-63 is severe.