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Trial registered on ANZCTR


Registration number
Help: Registration number
ACTRN12626001278325
Ethics application status
Help: Ethics application status
Approved
Date submitted
Help: Date submitted
16/09/2026
Date registered
Help: Date registered
26/10/2026
Date last updated
Help: Date last updated
26/10/2026
Date data sharing statement initially provided
Help: Data sharing statement date
26/10/2026
Type of registration
Help: Type of registration
Prospectively registered

Titles & IDs
Public title
The PROTECT-PD Study: Evaluating Probucol's preliminary efficacy on disease progression in Parkinson's disease - Cohort 2
Scientific title
The PROTECT-PD Study: Evaluating Probucol's preliminary efficacy on disease progression in Parkinson's disease - A randomised, double-blind, placebo-controlled, multicentre trial
Additional trial identifiers [1] 318455 0
Nil
Universal Trial Number (UTN)
Trial acronym
PRO-PD2025
Related trial records
PROTECT-PD consists of two cohorts within the study. Cohort 1 recruits individuals who have received a Parkinson’s disease diagnosis within the past three years - cohort 1 is registered under ACTRN12626000740392. Individuals diagnosed more than three years ago may be eligible for Cohort 2, with further details available under this registration.

Health condition
Health condition(s) studied:
Parkinson's Disease 343628 0
Condition category
Condition code
Neurological 339735 339735 0 0
Parkinson's disease

Intervention/exposure
Study type
Interventional
Description of the intervention or exposure
PROTECT-PD Cohort 2 is an Open-label, single-arm study evaluating the safety, tolerability, and feasibility of Probucol in individuals with more advanced Parkinson's Disease (PD), in whom disease-modifying intervention remains an unmet clinical need.

Treatment:
Chemical name: 4,4’-[Propan-2,2-diylbis(sulfandiyl)]bis[2,6-bis(1,1- dimethylethyl) phenol]
The proposed dose of Probucol for this protocol adopts contemporary usage published in contemporary clinical trials at 500mg twice a day. Probucol will be supplied in a commercially available form known as Lorelco and taken as tablets orally.

Study medication will commence (day 1, week 1) with a titration escalation design.

Subjects will be dosed as:
Weeks 1: 1 x 250 mg Lorelco™ taken orally once daily in the morning, with food.
Week 2: 1 x 250 mg Lorelco™ taken orally once daily in the morning, with food. 1 x 250 mg Lorelco™ taken in the evening, with food (total dose: 500 mg/day)
Week 3 – 78: 2 x 250 mg Lorelco™ taken in the morning, with food. 2 x 250 mg Lorelco™ taken in the evening, with food (total dose: 1000 mg/day). Unused medication is to be returned at every visit to monitor drug compliance.
Intervention code [1] 335363 0
Treatment: Drugs
Description of the comparator or control
Participants serve as their own historical controls relative to a baseline observation period and to published natural-history datasets. The baseline measurement is taken immediately prior to commencing on the study medication.
Control group
Uncontrolled

Outcomes
Primary outcome [1] 346905 0
To evaluate the safety of Probucol in individuals with advanced PD. This outcome will be assessed as a composite primary outcome.
Timepoint [1] 346905 0
Throughout the trial entirety and 4 weeks post cessation of treatment.
Primary outcome [2] 346906 0
To evaluate the treatment tolerability of Probucol in individuals with advanced PD. Dose modifications, interruptions, and discontinuations due to adverse events will all be assessed as a composite primary outcome.
Timepoint [2] 346906 0
Throughout the trial entirety
Primary outcome [3] 346907 0
To evaluate the feasibility outcomes of Probucol in individuals with advanced PD. This outcome will be assessed as a composite primary outcome.
Timepoint [3] 346907 0
Retention - assessed post-initiation of treatment and up until week 78; Recruitment rate - assessed monthly from recruitment commencement to recruitment closure; Protocol adherence - assessed at every participant visit from treatment commencement to week 78 post-treatment commencement; Assessment completion rate - assessed per participant visit from treatment commencement to week 78 post-treatment commencement
Secondary outcome [1] 468105 0
To explore the effect of Probucol on motor function of PD in individuals with advanced disease. All measures will be assessed together as a composite secondary outcome.
Timepoint [1] 468105 0
Baseline, week 12, 26, 52, 78
Secondary outcome [2] 468106 0
To explore the effect of Probucol on non-motor symptoms of PD in individuals with advanced disease. All measures will be assessed together as a composite secondary outcome.
Timepoint [2] 468106 0
Baseline, week 12, 26, 52, 78
Secondary outcome [3] 468107 0
To explore the effect of Probucol on quality of life of PD in individuals with advanced disease. All measures will be assessed together as a composite secondary outcome.
Timepoint [3] 468107 0
Baseline, week 12, 26, 52, 78
Secondary outcome [4] 468108 0
To explore the effect of Probucol on biological markers of PD in individuals with advanced disease. This outcome will be assessed as a composite outcome.
Timepoint [4] 468108 0
Baseline, week 12, 26, 52, 78

Eligibility
Key inclusion criteria
- Must have given written informed consent before any study-related activities are carried out and must be able to understand the full nature and purpose of the trial, including possible risks and adverse effects
- Parkinson’s disease confirmed by UK Parkinson’s Disease Society Brain Bank Criteria
- Disease duration greater than or equal to 3 years from documented motor onset.
- Modified Hoehn & Yahr stage 2.5–4 in the ON state (ambulatory; not wheelchair dependent).
- On stable, optimised PD medication regimen for greater than or equal to 3 months prior to baseline, expected to remain stable for the first 6 months of follow-up.
- Must be able to safely swallow the investigational product, with or without standard adaptive swallowing strategies
- MoCA greater than or equal to 21 (excludes Parkinson’s dementia)
- Reliable study partner available (e.g. family member or close friend who spends a lot of time with you each week) and willing to attend key visits, assist with diaries and patient-reported outcomes.
- Be willing and able to comply with all study assessments and adhere to the protocol
schedule and restrictions.
Minimum age
40 Years
Maximum age
No limit
Sex
Both males and females
Healthy volunteers
No
Key exclusion criteria
1. Clinical or imaging features suggesting atypical or secondary parkinsonism (PSP, MSA, CBS, DLB, vascular or drug-induced parkinsonism, or greater than or equal to 1 MDS absolute exclusion criterion).
2. Modified Hoehn & Yahr stage 5 (wheelchair-dependent or bedbound); unable to perform timed motor assessments.
3. Patients on a stable regimen of device-aided or infusion therapy may remain eligible, at the investigator’s discretion. Stable DBS (greater than or equal to 12 months, with no anticipated parameter changes) is permitted, at the investigator’s discretion.
4. History of significant drug induced QT interval prolongation.
5. Evidence of abnormal cardiac function as defined by any of the following:
a) Myocardial infarction within 6 months of Week 1, Day 1
b) Symptomatic congestive heart failure (New York Heart Association > Class II)
c) Unstable angina
d) Unstable atrial fibrillation including paroxysmal atrial fibrillation. Medicated, stable atrial fibrillation will be assessed on a case-by-case basis
e) Frequent multifocal ventricular arrhythmia
6. Gastrointestinal conditions that, in the opinion of the Investigator, could affect the absorption of study drug.
7. Use of the below medications, supplements, or consumption of foods within 7 days of first administration of Lorelco™, and for the duration of the study. These include (but are not limited to):
a. Medications:
i. *Strong QT prolongation inducers should be assessed on a case-by-case basis
at the discretion of the investigator
b. With significant central anticholinergic effects,
c. Any investigational treatment for PD
d. Foods: Grapefruit or Seville orange (or grapefruit- or Seville orange-containing
products, including juices)
8. Stroke with residual deficit affecting motor assessment, demyelinating disease, TBI sequelae, or normal-pressure hydrocephalus.
9. Current diagnosis of cancer (within 3 years) and/or undergoing chemotherapy, with exception to non-melanoma skin cancers such as basal or squamous cell carcimona in situ,
10. Significant head injury within 5 years
11. Electrolyte imbalance (e.g. on high steroids, pituitary tumours and Addison disease)
12. Hypokalaemia, hypomagnesaemia and hypocalcaemia
13. Major surgery is planned during the conduct of the trial, or a clinical event has occurred in the six months preceding study inclusion that may compromise ability to participate for the duration of the study,
14. History of stroke with residual cognitive or motor deficits
15. Current diagnosis with a psychiatric disorder such as major depression, bipolar disorder or schizophrenia where the condition is affecting daily functioning
16. Other excluded medications will be those that are specifically contraindicated with Probucol, based on historic clinical indications for the treatment of cardiovascular disease.
17. Self-reported active human immunodeficiency virus (HIV-1 or HIV-2), hepatitis B (HBsAg) or hepatitis C virus (HCV).
18. Any inflammatory or chronic pain condition that necessitates regular use of opiates/opioids,
19. Major surgery within 28 days of the pre-baseline visit, or minor surgical procedures within 7 days of pre-baseline.
20. For women of childbearing potential, a hCG pregnancy test > 5 U/L at screening, or on Day 1, prior to dose administration.
21. Pregnant or breast-feeding (or planning to breastfeed) while on study through 15 days after the last dose of study drug.
22. Hypersensitivity or other clinically significant reaction to the study drug or its inactive ingredients.
23. Known substance abuse or medical, psychological, or social conditions that, in the opinion of the Investigator, may interfere with the patient’s participation in the clinical study or evaluation of the clinical study results.

Study design
Purpose of the study
Treatment
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Single group
Other design features
Phase
Phase 2
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
4/01/2027
Actual
Date of last participant enrolment
Anticipated
8/01/2029
Actual
Date of last data collection
Anticipated
22/07/2030
Actual
Sample size
Target
80
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
WA
Recruitment hospital [1] 30224 0
Perron Institute for Neurological and Translational Science - Nedlands
Recruitment postcode(s) [1] 46618 0
6009 - Nedlands

Funding & Sponsors
Funding source category [1] 323036 0
Other
Name [1] 323036 0
Perron Institute for Neurological and Translational Science
Country [1] 323036 0
Australia
Primary sponsor type
University
Name
Curtin University
Address
Country
Australia
Secondary sponsor category [1] 325979 0
None
Name [1] 325979 0
Address [1] 325979 0
Country [1] 325979 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 321441 0
Bellberry Human Research Ethics Committee I
Ethics committee address [1] 321441 0
Ethics committee country [1] 321441 0
Australia
Date submitted for ethics approval [1] 321441 0
02/07/2026
Approval date [1] 321441 0
12/08/2026
Ethics approval number [1] 321441 0

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 153738 0
Dr Wai Yan Yau
Address 153738 0
Perron Institute for Neurological and Translational Science. 8 Verdun Street, Perth, WA 6009
Country 153738 0
Australia
Phone 153738 0
+61 402811690
Fax 153738 0
Email 153738 0
[email protected]
Contact person for public queries
Name 153739 0
Dr Virginie Lam
Address 153739 0
Curtin University, Building 305, Kent street, Bentley 6102
Country 153739 0
Australia
Phone 153739 0
+61 468 532 458
Fax 153739 0
Email 153739 0
[email protected]
Contact person for scientific queries
Name 153740 0
Prof. John Mamo
Address 153740 0
Curtin University, Building 305, Kent street, Bentley 6102
Country 153740 0
Australia
Phone 153740 0
+61 08 9266 7232
Fax 153740 0
Email 153740 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
No


What supporting documents are/will be available?

No Supporting Document Provided


Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.