Trial Review

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Trial registered on ANZCTR


Registration number
Help: Registration number
ACTRN12626001126303
Ethics application status
Help: Ethics application status
Approved
Date submitted
Help: Date submitted
30/06/2026
Date registered
Help: Date registered
10/09/2026
Date last updated
Help: Date last updated
10/09/2026
Date data sharing statement initially provided
Help: Data sharing statement date
10/09/2026
Type of registration
Help: Type of registration
Prospectively registered

Titles & IDs
Public title
A study evaluating the safety and effectiveness of SIR9900 compared with placebo in adults with VEXAS syndrome
Scientific title
A Randomized, Double-Blind, Placebo-Controlled Study to Investigate the Efficacy and Safety of SIR9900 in Patients with VEXAS Syndrome (SIVEX)
Additional trial identifiers [1] 317744 0
n/A
Universal Trial Number (UTN)
Trial acronym
Related trial records

Health condition
Health condition(s) studied:
VEXAS syndrome 342643 0
Condition category
Condition code
Inflammatory and Immune System 338785 338785 0 0
Autoimmune diseases
Human Genetics and Inherited Disorders 339424 339424 0 0
Other human genetics and inherited disorders
Blood 339521 339521 0 0
Other blood disorders

Intervention/exposure
Study type
Interventional
Description of the intervention or exposure
Participants will be randomised to receive SIR9900 20 mg, SIR9900 30 mg, or matching placebo orally once daily, together with permitted background treatment. Double-blind treatment will continue for up to 24 weeks, after which eligible participants may enter an open-label treatment period through Week 48. Treatment adherence is assessed at scheduled study visits using study treatment records. For this study, standard care consists of protocol-permitted background glucocorticoid treatment managed by the Investigator according to the participant’s clinical needs and the study protocol.
Intervention code [1] 334583 0
Treatment: Drugs
Description of the comparator or control
Control Arm (Arm 3) – Placebo: Participants will receive three matching placebo tablets orally once daily during the double-blind treatment period, together with permitted background treatment. The placebo contains no active study drug and therefore does not have a dose in milligrams. The placebo regimen is matched to the study treatment regimen to maintain blinding across both active intervention arms.
Control group
Placebo

Outcomes
Primary outcome [1] 345983 0
Proportion of participants achieving Overall Clinical Response (clinical response or better)
Timepoint [1] 345983 0
Assessed at scheduled study visits from commencement of the study intervention through the end of Week 24 post-intervention commencement, with the primary analysis conducted at the end of Week 24.
Secondary outcome [1] 464032 0
Incidence of treatment-emergent adverse events.
Timepoint [1] 464032 0
Assessed continuously from the first administration of study treatment through 28 days after the last administration, up to Week 52 post-intervention commencement.

Eligibility
Key inclusion criteria
Adults aged 18 years or older.
Genetically confirmed VEXAS syndrome.
Active disease meeting the protocol-defined eligibility criteria.
Stable background treatment, if applicable.
Able and willing to provide written informed consent and comply with study procedures.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Healthy volunteers
No
Key exclusion criteria
Prohibited concomitant medications include hypomethylating agents; non-glucocorticoid anti-inflammatory and haematological support therapies; antiplatelet therapy other than permitted low-dose aspirin; other investigational therapies; CYP1A2 substrates with a narrow therapeutic window; strong CYP3A inhibitors or inducers; strong CYP2C8 inhibitors; and non-prescription or herbal products with clinically relevant interaction potential.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Central randomisation using an interactive web response system (IWRS). Allocation was concealed until participant randomisation.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computer-generated random allocation sequence.
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Other design features
Phase
Phase 2
Type of endpoint/s
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
21/09/2026
Actual
Date of last participant enrolment
Anticipated
31/05/2027
Actual
Date of last data collection
Anticipated
29/05/2028
Actual
Sample size
Target
110
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
ACT,NSW,NT,QLD,SA,TAS,WA,VIC
Recruitment outside Australia
Country [1] 28268 0
China
State/province [1] 28268 0
Country [2] 28269 0
New Zealand
State/province [2] 28269 0

Funding & Sponsors
Funding source category [1] 321623 0
Commercial sector/Industry
Name [1] 321623 0
Sironax USA, Inc.
Country [1] 321623 0
United States of America
Primary sponsor type
Commercial sector/Industry
Name
Sironax USA, Inc.
Address
Country
United States of America
Secondary sponsor category [1] 325200 0
None
Name [1] 325200 0
Address [1] 325200 0
Country [1] 325200 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 320148 0
Royal Melbourne Institute of Technology Human Research Ethics Committee
Ethics committee address [1] 320148 0
Ethics committee country [1] 320148 0
Australia
Date submitted for ethics approval [1] 320148 0
29/05/2026
Approval date [1] 320148 0
17/06/2026
Ethics approval number [1] 320148 0

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

Contacts
Principal investigator
Name 149602 0
Prof Michael Leahy
Address 149602 0
Royal Perth Hospital, 197 Wellington Street, Perth, Western Australia 6000
Country 149602 0
Australia
Phone 149602 0
+61438384482
Fax 149602 0
Email 149602 0
[email protected]
Contact person for public queries
Name 149603 0
Valon Latifi
Address 149603 0
Sironax Aus Pty Ltd, Level 40, 2–26 Park Street, Sydney, NSW 2000
Country 149603 0
Australia
Phone 149603 0
+61401208760
Fax 149603 0
Email 149603 0
[email protected]
Contact person for scientific queries
Name 149604 0
Valon Latifi
Address 149604 0
Sironax Aus Pty Ltd, Level 40, 2–26 Park Street, Sydney NSW 2000, Australia.
Country 149604 0
Australia
Phone 149604 0
+61401208760
Fax 149604 0
Email 149604 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.