Safety and Efficacy of STL303 In Patients With Primary Immunoglobulin A (IgA) Nephropathy

May 24, 2026 updated by: Sitala Bio LTD

A Multicenter, Randomised, Double-Blinded, Placebo-Controlled Study to Evaluate the Safety and Efficacy of STL303 In Patients With Primary Immunoglobulin A (IgA) Nephropathy

This is a multicenter, randomized, double-blind, placebo controlled Phase IIb study to explore the efficacy and safety of STL303 capsules in IgAN patients. About 15 patients dignosed with primary IgAN will be enrolled and randomized to three cohorts and take different dosage of STL303 or placebo capsules orally according to protocol.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is a multicenter, randomized, double-blind, placebo-controlled study in approximately 15 patients with primary IgA nephropathy (IgAN).

Participants receiving background therapy will be randomized in a 1:1:1 ratio to receive STL303 capsules dose 1, dose 2, or placebo, administered orally once daily.

The study aims to evaluate the efficacy and safety of STL303 in patients with primary IgAN and to identify the optimal clinical dose.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
15

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Clinical Operations Manager
  • Phone Number: +61 421 585707
  • Email: studies@sitala.com

Study Locations

  • Australia
    • Queensland
      • Woolloongabba, Queensland, Australia, 4102
        • Research Site
    • Victoria
      • Clayton, Victoria, Australia, 3168
        • Research Site
      • Saint Albans, Victoria, Australia, 3021
        • Research Site

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Male and female patients aged 18 years and older, with primary IgAN confirmed by renal biopsy:
  2. eGFR (Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI] formula) greater than or equal to 30 mL/min/1.73 m2 at screening and after completion of run-in.
  3. UPCR greater than or equal to 0.75 g/g at screening and after completion of run-in.
  4. Vaccinated against Neisseria meningitidis and Streptococcus pneumoniae before the first dose.
  5. Have received stable treatment with RASis (ACEi or ARB) at the maximum recommended dose or MTD for at least 90 days prior to the first dose.
  6. If the patient has been treated with SGLT2i, diuretics, other antihypertensive treatments, ERA, and/or hydroxychloroquine for IgAN prior to the first dose, the drug should also be used stably for at least 90 days.

Exclusion Criteria:

  1. Secondary IgAN or unclear exclusion of secondary causes.
  2. Rapidly progressive IgAN (eGFR decline greater than or equal to 50% in 3 months, or less than 50% but at high risk).
  3. Other systemic diseases causing proteinuria/CKD or severe urinary obstruction.
  4. Known or suspected immunodeficiency or hereditary complement deficiency.
  5. Any organ transplant recipients except corneal.
  6. Poorly controlled blood pressure (SBP greater than 150 or DBP great than 90).
  7. Use of immunosuppressive drugs within 90 days or 5 half-lives.
  8. Prior oral budesonide (Nefecon/Tarpeyo/Kinpeygo) within 6 months.
  9. Prior complement inhibitors within 30 days, 5 half-lives, or residual effect period.
  10. Major systemic diseases preventing participation (e.g., NYHA IV, severe pulmonary disease).
  11. Significantly abnormal liver function (greater than 3× ULN enzymes or greater than 2× ULN bilirubin).
  12. QTcF greater than 500 ms.
  13. History of malignancy within 5 years (exceptions apply).
  14. History of meningococcal, pneumococcal, or Hib infection.
  15. Chronic/recurrent infections in past year (e.g., liver abscess, pyelonephritis).
  16. Active systemic infections within 2 weeks or fever greater than 38°C within 7 days.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Placebo Comparator: Placebo
Participants will receive placebo
Drug: Placebo capsule
Placebo arm participants will receive placebo capsules
Experimental: STL303 dose level 1
Participants will receive STL303 dose level 1
Drug: STL303
STL303 arm participants will receive a specific dose of STL303
Experimental: STL303 Dose Level 2
Participants will receive STL303 dose level 2
Drug: STL303
STL303 arm participants will receive a specific dose of STL303

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Treatment emergent adverse events (TEAEs), adverse events (AEs) and serious adverse events (SAEs)
Time Frame: Adverse events will be closely monitored, and participants will report to the clinic on Days 7, 14, 30, 45, 60, 90, 135 and at end of treatment on Day 180. On Day 210 an End of study safety follow up will also be conducted.
All participants will be observed for any AE during the clinical study, including abnormalities in clinical symptoms and vital signs, physical examination, laboratory tests, and 12-lead ECG. Incidence, severity, and relationship of TEAEs and serious adverse events (SAEs) to STL303. Possible adverse events include: palpitations, nausea, vomiting, dizziness, sore throat, upper respiratory infection, loss of appetite, high temperature, chest discomfort, weakness, rash, headache, lethargy (feeling tired and low on energy) and urinary tract infection.
Adverse events will be closely monitored, and participants will report to the clinic on Days 7, 14, 30, 45, 60, 90, 135 and at end of treatment on Day 180. On Day 210 an End of study safety follow up will also be conducted.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in blood creatinine level
Time Frame: Blood sampling pre-dose on Days 1 (baseline), 14, 30, 45, 60, 90 and 180
Peripheral blood sampling
Blood sampling pre-dose on Days 1 (baseline), 14, 30, 45, 60, 90 and 180
Change in eGFR slope
Time Frame: Blood sampling pre-dose on Days 1 (baseline), 14, 30, 45, 60, 90 and 180
Peripheral blood sampling
Blood sampling pre-dose on Days 1 (baseline), 14, 30, 45, 60, 90 and 180
Maximum Concentration at steady-state (Tmax, ss) of STL303
Time Frame: Pre-dose on Days 1, 7, 14, 60, 90, 135, and 180. On Day 30 pre-dose and at 1 hour (± 5 minutes), 2 hours (± 5 minutes), 4 hours (± 10 minutes), 6 hours (± 10 minutes), 8 hours (± 10 minutes), 12 hours (± 10 minutes), and 24 hours (± 1 hour) after dosing
Measure time to reach maximum concentration at steady-state (Tmax, ss) at steady state.
Pre-dose on Days 1, 7, 14, 60, 90, 135, and 180. On Day 30 pre-dose and at 1 hour (± 5 minutes), 2 hours (± 5 minutes), 4 hours (± 10 minutes), 6 hours (± 10 minutes), 8 hours (± 10 minutes), 12 hours (± 10 minutes), and 24 hours (± 1 hour) after dosing
Maximum plasma concentration at steady-state (Cmax, ss) of STL303
Time Frame: Pre-dose on Days 1, 7, 14, 60, 90, 135, and 180. On Day 30 pre-dose and at 1 hour (± 5 minutes), 2 hours (± 5 minutes), 4 hours (± 10 minutes), 6 hours (± 10 minutes), 8 hours (± 10 minutes), 12 hours (± 10 minutes), and 24 hours (± 1 hour) after dosing
Measure maximum plasma concentration at steady-state (Cmax, ss) at steady state.
Pre-dose on Days 1, 7, 14, 60, 90, 135, and 180. On Day 30 pre-dose and at 1 hour (± 5 minutes), 2 hours (± 5 minutes), 4 hours (± 10 minutes), 6 hours (± 10 minutes), 8 hours (± 10 minutes), 12 hours (± 10 minutes), and 24 hours (± 1 hour) after dosing
Trough plasma concentration at steady-state of STL303
Time Frame: Pre-dose on Days 1, 7, 14, 60, 90, 135, and 180. On Day 30 pre-dose and at 1 hour (± 5 minutes), 2 hours (± 5 minutes), 4 hours (± 10 minutes), 6 hours (± 10 minutes), 8 hours (± 10 minutes), 12 hours (± 10 minutes), and 24 hours (± 1 hour) after dosing
Measure trough plasma concentration at steady-state (Cmin, ss /Ctrough, ss),
Pre-dose on Days 1, 7, 14, 60, 90, 135, and 180. On Day 30 pre-dose and at 1 hour (± 5 minutes), 2 hours (± 5 minutes), 4 hours (± 10 minutes), 6 hours (± 10 minutes), 8 hours (± 10 minutes), 12 hours (± 10 minutes), and 24 hours (± 1 hour) after dosing
Area under plasma concentration-time curve for STL303
Time Frame: Pre-dose on Days 1, 7, 14, 60, 90, 135, and 180. On Day 30 pre-dose and at 1 hour (± 5 minutes), 2 hours (± 5 minutes), 4 hours (± 10 minutes), 6 hours (± 10 minutes), 8 hours (± 10 minutes), 12 hours (± 10 minutes), and 24 hours (± 1 hour) after dosing
Measure the area under the plasma concentration-time curve over one dosing interval at steady state (AUCtau)
Pre-dose on Days 1, 7, 14, 60, 90, 135, and 180. On Day 30 pre-dose and at 1 hour (± 5 minutes), 2 hours (± 5 minutes), 4 hours (± 10 minutes), 6 hours (± 10 minutes), 8 hours (± 10 minutes), 12 hours (± 10 minutes), and 24 hours (± 1 hour) after dosing
Alternative Pathway Activity (Wieslab Assay)
Time Frame: Pre-dose and post-dose on Day 1 and Day 14; pre-dose on Days 7, 60, 90, 135, and 180; intensive time points (pre-dose, 1, 2, 4, 6, 8, 12, and 24 hours post-dose) on Day 30
Change from baseline in complement alternative pathway (AP) functional activity as measured by the Wieslab assay in serum
Pre-dose and post-dose on Day 1 and Day 14; pre-dose on Days 7, 60, 90, 135, and 180; intensive time points (pre-dose, 1, 2, 4, 6, 8, 12, and 24 hours post-dose) on Day 30
Urinary Complement Biomarker C3a
Time Frame: Day 1, Day 7 (FMV only), Day 14 (FMV only), Day 30, Day 60, Day 90, Day 135 (FMV only), and Day 180 (all pre-dose)
Change from baseline in urinary levels of C3a, measured in first morning void (FMV) and 24-hour urine samples collected midstream first morning void (FMV) Urine sampling
Day 1, Day 7 (FMV only), Day 14 (FMV only), Day 30, Day 60, Day 90, Day 135 (FMV only), and Day 180 (all pre-dose)
Plasma Soluble Terminal Complement Complex (sC5b-9)
Time Frame: Day 1 through Day 180 (pre-dose at scheduled visits)
Change from baseline in plasma levels of soluble terminal complement complex (sC5b-9), a marker of terminal complement activation
Day 1 through Day 180 (pre-dose at scheduled visits)
Complement Factor B Cleavage Fragment (Bb)
Time Frame: Day 1 through Day 180 (pre-dose at scheduled visits)
Change from baseline in plasma levels of complement factor B cleavage fragment (Bb), a marker of alternative pathway activation
Day 1 through Day 180 (pre-dose at scheduled visits)
Change from baseline urine protein-to-creatinine ratio (UPCR)
Time Frame: 24-hour urine collection pre-dose on Days 1 (baseline), 30, 60, 90 and 180
Change in baseline 24-hour urine collection
24-hour urine collection pre-dose on Days 1 (baseline), 30, 60, 90 and 180
Change in UPCR
Time Frame: 24-hour urine collection pre-dose on Days 1 (baseline), 30, 60 and 90
Change in baseline 24-hour urine collection
24-hour urine collection pre-dose on Days 1 (baseline), 30, 60 and 90
Change in urine albumin-to-creatinine ratio (UACR)
Time Frame: 24-hour urine collection pre-dose on Days 1 (baseline), 30, 60, 90 and 180
Change in baseline 24-hour urine collection
24-hour urine collection pre-dose on Days 1 (baseline), 30, 60, 90 and 180
Change urine protein excretion (UPE),
Time Frame: 24-hour urine collection pre-dose Days 1 (baseline), 30, 60, 90 and 180
Change in baseline 24-hour urine collection
24-hour urine collection pre-dose Days 1 (baseline), 30, 60, 90 and 180

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sitala Bio LTD

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Eugenia Pedagogos, Western Health (Sunshine Hospital)

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 7, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 18, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 26, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 28, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 24, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • STL303-201

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared because participant consent and ethics approvals do not permit public data sharing. A clinical study report will be prepared at the end of the study and result will be shared with research sites and investigators will be able to discuss results with participants if needed.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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