The goal of this clinical trial is to learn if this study drug, ENERGI-F705 Tablets, is safe and works to treat participants who have Parkinson's disease and are currently on standard-of-care antiparkinsonian medications. The main question it aims to answer is:
Does ENERGI-F705 Tablets work to treat Parkinson's disease when used with standard-of-care treatment?
Investigators will compare the three treatment groups, high-dose ENERGI-F705 Tablets (120 milligrams twice daily), low-dose ENERGI-F705 Tablets (60 milligrams twice daily), and placebo tablets (a look-alike substance that contains no drug), to see if ENERGI-F705 Tablets work to treat Parkinson's disease.
Participants will:
* Take the study drugs twice a day for 72 weeks in the treatment group * Take routine use of standard-of-care antiparkinsonian medications throughout the study * Visit the outpatient department at scheduled visits, ranging from Day 1 to approximately every 1 to 4 weeks thereafter, for checkups and tests
With either gender aged ≥ 40 to ≤ 75 years old at Visit 1 (Screening Visit)
Has been diagnosed with idiopathic Parkinson's disease (defined by the Movement Disorder Society (MDS) Clinical Diagnostic Criteria for Parkinson's disease) for ≥ 2 years prior to or at Visit 2 (Day 1)
Has a modified Hoehn and Yahr stage of 2 to 3 while assessed in the medication-off state at Visit 1 (Screening Visit)
With MDS-UPDRS Part III (motor examination) score of 15 to 60 while assessed in the medication-off state at Visit 1 (Screening Visit)
Has been diagnosed with atypical Parkinson's disease or secondary parkinsonism
Deep brain stimulation
Pallidotomy
Thalamotomy