Atacicept Demonstrating Dose RESponSe

Study Overview
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Brief Summary
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Systemic lupus erythematosis (SLE) is an autoimmune disease, meaning that the body's immune system attacks its own organs and tissues. Within the immune system, B-cells and plasma cells make proteins called antibodies, which in autoimmune disease can bind to one's own tissues and are thus referred to as autoantibodies. Atacicept blocks 2 factors in the body, called BLyS and APRIL, which are important for the maintenance of B-cells and plasma cells, and thus the production of antibodies. This study will assess whether treatment with atacicept can reduce SLE disease activity. Atacicept is still an experimental drug, meaning that it is not available outside of a clinical trial, and that its potential benefits and risks have not been fully determined. A total of 175 subjects are planned to be randomized (35 subjects per treatment arm) in a 1:1:1:1:1 ratio to receive either atacicept 5 mg, atacicept 25 mg, atacicept 75 mg, atacicept 115 mg or matching placebo, given subcutaneously once weekly for 24 weeks. The primary objective of the trial is to evaluate the efficacy of atacicept compared to placebo in reducing SLE disease activity in subjects treated with standard of care (SoC) therapy and to investigate the dose-response relationship. The secondary objectives of the trial are: To evaluate the effect of atacicept in reducing corticosteroid usage To evaluate the safety and tolerability profile of atacicept in subjects with SLE To confirm the PK and PD profiles of atacicept in SLE subjects To evaluate the changes in the Medical Outcomes Study Short Form General Health Survey [SF-36].

Official Title
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A Phase II, Multi-Center, Randomized, Double-Blind, Placebo-Controlled, Multidose, 24-Week Dose-Response Study to Evaluate the Efficacy and Safety of Atacicept in Subjects With Systemic Lupus Erythematosus (SLE)

Conditions
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Systemic Lupus Erythematosus

Intervention / Treatment
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* Drug: Placebo
* Drug: Atacicept
* Drug: Atacicept
* Drug: Atacicept
* Drug: Atacicept


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female of ≥18 years of age Written informed consent Diagnosis of SLE satisfying at least 4 out of the 11 ACR criteria during the course of their illness Disease duration of at least 6 months SLEDAI-2K score ≥ 6 at screening Positive test results for antinuclear antibody (ANA) (HEp-2 ANA ≥1:80) and/or anti-double-stranded deoxyribonucleic acid (dsDNA) (≥30 IU/mL) at screening Negative serum pregnancy test and highly effective method of contraception for woman of childbearing potential. Exclusion Criteria: Increase in dosing of corticosteroids within 2 weeks prior to screening Introduction of MMF within 3 months prior to TD1 or increase in dosing within 1 month before screening Change in dosing of immunosuppressants or corticosteroids during the screening period Serum IgG < 6g/L Estimated Glomerular Filtration Rate (GFR) <50 mL/min/1.73m² Urinary protein:creatinine ratio >2 mg/mg History of demyelinating disease Breastfeeding or pregnancy Legal or limited legal capacity Additional exclusion criteria also apply

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Arm 1<br> | Drug: Placebo<br>* Matching placebo administered by subcutaneous injection, once weekly<br>|
| Experimental: Arm 2<br> | Drug: Atacicept<br>* Atacicept 5 mg administered by subcutaneous injection, once weekly<br>|
| Experimental: Arm 3<br> | Drug: Atacicept<br>* Atacicept 25 mg administered by subcutaneous injection, once weekly<br>|
| Experimental: Arm 4<br> | Drug: Atacicept<br>* Atacicept 75 mg administered by subcutaneous injection, once weekly<br>|
| Experimental: Arm 5<br> | Drug: Atacicept<br>* Atacicept 115 mg administered by subcutaneous injection, once weekly<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline (trial day 1) in SLEDAI-2K Responder Index-50 (SRI-50) at week 24 of therapy | The SRI-50 is a modification of the SLEDAI-2K, and allows detection of partial improvements (at least 50%) in SLE signs and symptoms assessed by SLEDAI-2K (Systemic Lupus Erythamtosus Disease Activity Index- 2000). | 24 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline to Week 24 in corticosteroid dose |  | 24 weeks | 
| Change from baseline in serum Complement C3 levels at week 24 in subjects with low C3 at baseline |  | 24 weeks | 
| Change from baseline in serum Complement C4 levels at week 24 in subjects with low C4 at baseline |  | 24 weeks | 
| Change from baseline in anti-dsDNA antibodies (in subjects with anti dsDNA ≥30 IU/mL at baseline) and in ANA levels (in subjects with HEp-2 ANA ≥1:80 at baseline) at week 24 |  | 24 weeks | 
| Change from baseline in levels of total Ig and Ig classes (IgG, IgA, and IgM) at week 24 |  | 24 weekls | 
| The nature (preferred terms) and incidence of AEs | Frequency tables summarizing the observed number of AEs by System Organ Class (SOC) and preferred term will be presented per regimen | 24 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Rheumatology, Double-Blind, Placebo-Controlled, Multidose, Dose-Response, Phase II, Systemic Lupus Erythematosus, SLE, Atacicept