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CompletedNCT03371251Updated Mar 14, 2022Results posted

Study of BOS161721 in Systemic Lupus Erythematosus (SLE) Patients on a Background of Limited Standard of Care

A Phase 1/2 interventional study of BOS161721 and Placebo in Systemic Lupus Erythematosus, sponsored by Boston Pharmaceuticals. Completed at 68 sites in 12 countries. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2022-03-14.

Sponsored by Boston Pharmaceuticals · Phase 1/2, Interventional, and Treatment

Phase
Phase 1/2
Study type
Interventional
Enrollment
143
Allocation
Randomized
Ages
18 Years to 70 Years
Sex
All
01

Study summary

This study will be conducted to assess the safety, tolerability, and immunogenicity of repeat doses of BOS161721 (20 milligrams [mg], 60 mg, and 120 mg) administered subcutaneously in adult participants with moderately to severely active Systemic Lupus Erythematosus (SLE) on limited background standard of care treatment, in order to estimate the optimal dose.

BOS161721 at the chosen dose will be compared to placebo for response on the SLE Responder Index 4, with sustained reduction of oral corticosteroids, in the same participant population.

02

Conditions studied

  • Systemic Lupus Erythematosus

Keywords

  • Adults
  • BOS161721
  • standard of care
  • moderately to severely active Systemic Lupus Erythematosus
03

In context

Lupus Erythematosus, Systemic

1,222 studies on the registry are indexed under Lupus Erythematosus, Systemic; 399 are open to participants now.

This study's enrollment of 143 is above the median of 50 across 881 interventional studies indexed under Lupus Erythematosus, Systemic.

Browse Lupus Erythematosus, Systemic studies →

Lead sponsor

Boston Pharmaceuticals is the lead sponsor of 10 studies on the registry; none are open to participants now.

Of its 8 completed or terminated interventional studies of FDA-regulated products, 2 (25%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 70 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Men and women, ages 18 to 70 years, inclusive
  • Participants must be mentally capable of giving consent and there must be evidence of a personally signed and dated informed consent document indicating that the participant has been informed of all pertinent aspects of the study
  • Participants must have Systemic Lupus Erythematosus (SLE) as defined by meeting 4 of the Systemic Lupus International Collaborating Clinics classification criteria for SLE (with at least 1 clinical and 1 immunologic criterion OR Lupus nephritis as the sole clinical criterion in the presence of anti-nuclear antibodies (ANA) or anti-double stranded deoxyribonucleic acid (dsDNA) antibodies), either sequentially or simultaneously

  • At screening, participants must have at least 1 of the following:

    1. Elevated ANA ≥ 1:80 via immunofluorescent assay at the central laboratory
    2. Positive anti-dsDNA or anti-Smith (anti-Sm) above the normal level as determined by the central laboratory

  • At screening, the total Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score must be ≥ 8, including points from at least 1 of the following clinical components:

    a. Arthritis, rash, myositis, mucosal ulcers, pleurisy, pericarditis, and vasculitis Note: Points from lupus headache and organic brain syndrome will also be excluded from qualifying total and clinical SLEDAI-2K scores at screening and Day 0.

  • A clinical SLEDAI-2K score of ≥ 6 at screening at Day 0. Clinical SLEDAI-2K score is defined as follows:

    1. Contains points from arthritis, rash, myositis, mucosal ulcers, pleurisy, pericarditis, or vasculitis
    2. Excludes parameters which require central laboratory results: hematuria, pyuria, urinary casts, proteinuria, positive anti-dsDNA, decreased complement, thrombocytopenia, and leukopenia Note: Points from lupus headache and organic brain syndrome will also be excluded from qualifying total and clinical SLEDAI-2K scores at screening and Day 0.

  • Participants must have at least 1 qualifying A or 2Bs from the following manifestations of SLE, as defined by the British Isles Lupus Assessment Group (BILAG) criteria as modified for use in this study, which must be confirmed by the central data reviewer:

    1. BILAG A or B score in the mucocutaneous body system. If a BILAG B score is due to BILAG number 6, mild skin eruption, the CLASI activity score including erythema and scale/hypertrophy must be ≥ 3 excluding points from mucosal ulcers and alopecia.
    2. BILAG A or B score in the musculoskeletal body system due to active polyarthritis Note: Hips, shoulders, back, neck, and temporomandibular joints do not count towards the total number of joints with active synovitis.

If only one "B" and no "A" score is present in the mucocutaneous body system or in the musculoskeletal body system due to arthritis, then at least 1 "B" must be present in at least 1 other body system for a total of 2 "B" BILAG body system scores.

- Participants must be currently receiving at least 1 of the following:

  1. Administration for a minimum of 12 weeks, and a stable dose for at least 56 days (8 weeks prior to Day 0) of the following permitted steroid sparing agents: azathioprine (AZA), mycophenolate mofetil or mycophenolic acid, chloroquine, hydroxychloroquine, or methotrexate
  2. If AZA, myocophenolate mofetil, mycophenolic acid, hydroxychloroquine, or MTX were discontinued prior to screening, the washout period must be ≥ 12 weeks.
  3. Corticosteroids (CSs) (prednisone or prednisone-equivalent) at a stable dose of up to 30 mg/day for at least 6 weeks prior to Day 0

i. For participants whose only SLE treatment is CSs, the stable CS dose must be ≥ 10 mg/day for at least 6 weeks prior to Day 0 and no more than 30 mg/day at the time of randomization.

ii. Topical steroids may be used, but the dose must be stable for at least 6 weeks prior to Day 0. PRN topical steroids are not permitted.

  • Women of childbearing potential (WOCBP):

    1. Must have a negative serum pregnancy test at screening. Urine pregnancy test must be negative prior to first dose
    2. Must not be breastfeeding
    3. Must agree to follow instructions for method(s) of contraception for the duration of treatment with study drug plus 52 weeks
  • Men who are sexually active with WOCBP must agree to follow instructions for method(s) of contraception for the duration of treatment with study drug plus 52 weeks
  • Participants must demonstrate willingness and ability to comply with the scheduled study visits, treatment plans, laboratory tests, and other procedures

Exclusion criteria

Exclusion Criteria:

Participants presenting with any of the following will not be included in this study:

  • Drug-induced SLE, rather than "idiopathic" SLE
  • Other systemic autoimmune disease (eg, erosive arthritis, rheumatoid arthritis [RA], multiple sclerosis [MS], systemic sclerosis, or vasculitis not related to SLE). RA-Lupus overlap (Rupus), and secondary Sjogren syndrome are allowed.
  • Any major surgery within 6 weeks of study drug administration (Day 0) or any elective surgery planned during the course of the study

  • Any history or risk for tuberculosis (TB), specifically those with:

    1. Current clinical, radiographic, or laboratory evidence of active TB
    2. History of active TB
    3. Latent TB defined as positive QuantiFERON-TB Gold In Tube or other diagnostic test in the absence of clinical manifestations. Latent TB is not excluded if the participant has documented completion of adequate course of prophylactic treatment with regimen recommended by local health authority guideline, or the participant has started treatment with isoniazid, or other regimen recommended by local health authority guidelines for at least 1 month before Day 0 and continues to receive the prophylactic treatment during study until the treatment course is completed
  • Active or unstable lupus neuropsychiatric manifestations, including but not limited to any condition defined by BILAG A criteria, with the exception of mononeuritis multiplex and polyneuropathy, which are allowed
  • Severe proliferative lupus nephritis (World Health Organization Class III, IV), which requires or may require induction treatment with cytotoxic agents or high dose CSs
  • Concomitant illness that, in the opinion of the investigator or the Sponsor or their designee, is likely to require additional systemic glucocorticosteroid therapy during the study, (eg, asthma), is exclusionary. However, treatment for asthma with inhalational CSs therapy is allowed.
  • Use or planned use of concomitant medication outside of standard of baseline treatment for SLE from Day -1 or for any time during the study
  • Active and clinically significant infection (bacterial, fungal, viral, or other) within 60 days prior to first dose of study drug. Clinically significant is defined as requiring systemic parenteral antibiotics or hospitalization
  • A history of opportunistic infection, or a history of recurrent or severe disseminated herpes zoster or disseminated herpes simplex within the last 3 years
  • Chronic viral hepatitis B (HBV) and hepatitis C (HCV), unless participant received curative treatment for HCV and has a documented negative viral load, known human immunodeficiency virus (HIV), or acquired immunodeficiency syndrome (AIDS)-related illness
  • Cryptosporidium in the stool sample at screening
  • White blood cells \< 1,200/millimeters cubed (mm\^3) (1.2 × 10\^9/Liter [L]) at screening
  • Absolute neutrophil count \< 500/mm\^3 at screening
  • CD4+ count \< 150/microliter (µL) at screening
  • Platelets \< 50,000/mm\^3 (50 × 10\^9/L) or \< 35,000/mm\^3 (35 × 10\^9/L) if related to SLE, at screening
  • Hemoglobin \< 8 grams per deciliter (g/dL) or \< 7 g/dL at screening if related to SLE
  • Proteinuria > 3.0 g/day (3000 milligrams per day [mg/day]) at screening or equivalent level of proteinuria as assessed by protein/creatinine ratio (3 mg/mg or 339 milligrams per millimole [mg/mmol])
  • Serum creatinine > 2.0 mg/dL at screening or creatinine clearance \< 40 milliliters per minute (mL/minute) based on Cockcroft-Gault calculation
  • Serum alanine aminotransferase and/or serum aspartate aminotransferase > 2 × the upper limit of normal (ULN) at screening, unless explicitly related to lupus based on the investigator's judgment
  • Creatinine kinase > 3.0 × ULN at screening unless related to lupus myositis
  • Total bilirubin > 1.5 × ULN at screening (unless related to Gilbert's syndrome)
  • Any other laboratory test results that, in the opinion of the Investigator or the Sponsor or Sponsor's designee, might place a participant at unacceptable risk for participating in this study
  • History of allergic or anaphylactic reaction to any therapeutic or diagnostic monoclonal antibodies (mAb) (eg, IgG protein) or molecules made of components of mAbs
  • History substance and/or alcohol abuse, or dependence within the past 1 year, at the investigator's judgment
  • History of cancer within the last 5 years (except for cutaneous basal cell or squamous cell cancer, or cervical cancer in situ resolved by excision)
  • Any other severe acute or chronic medical or psychiatric condition, including recent (within the past year) medical conditions (eg, cardiovascular conditions, respiratory illnesses) that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator, Sponsor, or Sponsor's designee, would make the participant inappropriate for entry into this study
  • Investigational site staff members directly involved in the conduct of the trial and their family members, site staff members otherwise supervised by the investigator, or participants who are employees of the sponsor or directly involved in the conduct of the trial
  • Currently participating in, or who have participated in other interventional (drug or device) clinical study within 30 days or 5 half-lives of baseline, whichever is longer
  • Recent (within the past 12 months) or active suicidal ideation or behavior based on participant responding "yes" to question 3, 4, or 5 on the Columbia Suicide severity Rating Scale
  • Current or pending incarceration
  • Current or pending compulsory detainment for treatment of either a psychiatric or physical (eg, infectious disease) illness
  • Currently taking a total daily dose of > 30 mg morphine or morphine equivalent
  • Body mass index (BMI) ≥ 40.0
05

Study design

Phase
Phase 1 / Phase 2
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
143 participants (actual)

Study arms

  • Experimental
    Phase 1b: BOS161721 20, 60, 120 mg

    Participants will be randomized to receive a 20 milligram (mg), 60 mg, or 120 mg subcutaneous (SC) dose of BOS161721. Participants may receive a total of 7 SC monthly doses of BOS161721 on Days 0, 30, 60, 90, 120, 150, and 180, followed by safety follow-up visits on at Days 210, 240, and 270.

    Drug: BOS161721

  • Placebo comparator
    Phase 1b: Placebo 20, 60, 120 mg

    Participants will be randomized to receive a 20 mg, 60 mg, or 120 mg SC dose of placebo. Participants may receive a total of 7 SC monthly doses of placebo on Days 0, 30, 60, 90, 120, 150, and 180, followed by safety follow-up visits on at Days 210, 240, and 270.

    Drug: Placebo

  • Experimental
    Phase 2: BOS161721

    Participants will be randomized to receive a 120 mg SC dose of BOS161721 (as determined from Phase 1b of the study). Participants may receive a total of 7 SC monthly doses of BOS161721 on Days 0, 30, 60, 90, 120, 150, and 180, followed by safety follow-up visits on at Days 210, 240, and 270.

    Drug: BOS161721

  • Placebo comparator
    Phase 2: Placebo

    Participants will be randomized to receive a 120 mg SC dose of placebo (as determined from Phase 1b of the study). Participants may receive a total of 7 SC monthly doses of placebo on Days 0, 30, 60, 90, 120, 150, and 180, followed by safety follow-up visits on at Days 210, 240, and 270.

    Drug: Placebo

Interventions

  • DrugBOS161721

    SC administration

  • DrugPlacebo

    SC administration

06

What researchers measure

Primary outcomes

  1. Phase 1b: Number of Participants With Adverse Events (AEs)

    The safety, tolerability, and immunogenicity of repeat doses of BOS161721 (20, 60, and 120 mg) administered SC were assessed in adult participants with moderate to severe SLE on limited background standard of care treatment, in order to estimate the optimal dose.

    Time frame: Up to Day 270

  2. Phase 2: Number of Participants With an SLE Responder Index 4 (SRI-4) Response at Day 210

    The SRI-4 is a composite index of SLE disease improvement that consists of scores derived from the SLE Disease Activity Index 2000 (SLEDAI-2K), the British Isles Lupus Assessment Group (BILAG) 2004 Index and the Physician's Global Assessment (PGA). Response based on the SRI-4 is defined by: 1) ≥ 4-point reduction in the SLEDAI-2K total score; 2) no new severe disease activity (BILAG A organ score) or more than 1 new moderate organ score (BILAG B) compared with baseline; and 3) no deterioration from baseline in the PGA by ≥ 30 millimeters. The SLEDAI-2K total score falls between 0 and 105, with higher scores representing increased disease activity.The SRI-4 response in participants with moderate to severe SLE is associated with broad improvements in clinical and participant-reported outcomes.

    Time frame: Day 210

Secondary outcomes

  1. Phase 1b: Maximum Observed Concentration (Cmax)

    The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

    Time frame: Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180

  2. Phase 1b: First Time to Maximum Concentration (Tmax)

    The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

    Time frame: Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180

  3. Phase 1b: The Area Under the Plasma Concentration Versus Time Curve, From Time 0 to the Last Quantifiable Concentration (AUClast)

    The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

    Time frame: Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180

  4. Phase 1b: Terminal Elimination Half-life (t1/2)

    The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

    Time frame: Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180

  5. Phase 1b: Apparent Plasma Clearance After Extravascular Administration (CL/F)

    The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

    Time frame: Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180

  6. Phase 1b: Apparent Volume of Distribution After Extravascular Administration (Vz/F)

    The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

    Time frame: Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180

  7. Phase 1b: Mean Change From Baseline in Phosphorylated Signal Transducer and Activator of Transcription 3 (pSTAT3)

    The optimal dose of BOS161721 was selected based on safety, tolerability, PK and pharmacodynamic (PD) data in participants with moderate to severe SLE.

    Time frame: Baseline (Day 0); Days 30, 44, 60, and 90 (pre-dose [trough] samples only)

  8. Phase 1b: Mean Change From Baseline in Complement 3 (C3) and Complement (C4) Levels

    The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

    Time frame: Baseline (Day 0); Day 210

  9. Phase 1b: Mean Change From Baseline in Leukocyte Immunophenotype

    The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

    Time frame: Baseline (Day 0); Day 180

  10. Phase 1b: Mean Change From Baseline in Anti-double-stranded DNA (dsDNA) Autoantibodies at Each Visit

    The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE..

    Time frame: Baseline (Day 0); Days 30, 60, 90, 120, 150, 180, 210, 240, and 270

  11. Phase 1b: Mean Change From Baseline in Anti-Sjögren's Syndrome A and B (SSA, SSB)

    The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in subjects with moderate to severe SLE.

    Time frame: Baseline (Day 0); Day 180

  12. Phase 1b: Mean Change From Baseline in Anti-Smith Antibody (Sm)

    The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in subjects with moderate to severe SLE.

    Time frame: Baseline (Day 0); Day 180

  13. Phase 1b: Mean Change From Baseline in Antiphospholipid (APL) Autoantibodies (Beta 2 Glycoprotein, Cardiolipin IgG)

    The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

    Time frame: Baseline (Day 0); Day 180

  14. Phase 1b: Mean Change From Baseline in Abrogation of IL-21 Gene Signature

    The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

    Time frame: Baseline (Day 0); Days 15, 90, 180, and 270

  15. Phase 2: Number of Participants With an SRI-4, SRI-5, and SRI-6 Response at Each Visit

    The SRI-4 is a composite index of SLE disease improvement that consists of scores derived from the SLE Disease Activity Index 2000 (SLEDAI-2K) and the British Isles Lupus Assessment Group (BILAG) 2004 Index. Response based on the SRI-4 is defined by: 1) ≥ 4-point reduction in the SLEDAI-2K global score; 2) no new severe disease activity (BILAG A organ score) or more than 1 new moderate organ score (BILAG B); and 3) no deterioration from baseline in the Physician's Global Assessment (PGA) by ≥ 30 millimeters. The SRI-4 response in participants with moderate to severe SLE is associated with broad improvements in clinical and participant-reported outcomes. SRI-5 and SRI-6 are composite indices of SLE disease improvement that consist of scores derived from the SLEDAI-2K and the BILAG 2004 Index. The SRI-5 and SRI-6 are computed with a minimal five-point or six-point improvement in SLEDAI-2K being required, respectively.

    Time frame: Days 30, 60, 90, 120, 150, 180, 210, 240, and 270

  16. Phase 2: Number of Participants With a Sustained Reduction From Baseline of Oral Corticosteroid (CS) (≤ 7.5 mg/Day and < Day 0 Dose) Between Day 150 and Day 210

    Effect of BOS161721 compared with placebo for response on clinical indicators of SLE activity was assessed in adult participants with moderate to severe SLE on limited background standard of care treatment.

    Time frame: Day 150 to Day 210

  17. Phase 2: Number of Participants With New or Recurrent BILAG Flares (≥ 1 Qualifying BILAG A or > 1 Qualifying BILAG B) Through Day 210

    The BILAG-2004 index is an organ-specific 97-question assessment based on the principle of the doctor's intent to treat. Only clinical features attributable to SLE disease activity were recorded and based on the participant's condition in the last 4 weeks compared with the previous 4 weeks. It was scored as not present (0), improved (1), the same (2), worse (3), or new (4). Disease activity was graded separately for 9 body systems to 5 different grades (A to E) as follows: A is very active disease, B is moderate activity, C is mild stable disease, D is inactive now but previously active, and E indicates the organ was never involved. A shift from BILAG-2004 Grade A or B to a lower grade indicates a clinically relevant change in disease activity as the BILAG-2004 grades mirror the decision points for treatment interventions.

    Time frame: Days 30, 60, 90, 120, 150, 180, 210

  18. Phase 2: Number of Participants With Physician's Global Assessment (PGA) Worsening

    The PGA is used to assess Investigator's general impression on the patient's overall status of SLE disease activity via visual analogue scale (100 mm) with 0 being "very good, asymptomatic and no limitation of normal activities" with 100 mm being "most severe possible disease ever seen in all SLE patients". PGA worsening is defined as an increase of ≥ 30 mm from baseline.

    Time frame: Days 30, 60, 90, 120, 150, 180, and 210

  19. Phase 2: Number of Participants With a BILAG-based Composite Lupus Assessment (BICLA) Response at Day 210

    The BICLA is a responder index developed to measure response to therapy, and it includes scores from the BILAG, SLEDAI-2K, and Physician's Global Assessment (PGA). BICLA response is defined as: 1) at least 1 gradation of improvement in baseline BILAG 2004 scores in all body systems with moderate disease activity at entry (eg, all B \[moderate disease\] scores falling to C \[mild\], or D \[no activity\]); 2) no new BILAG A or more than 1 new BILAG B scores; 3) no worsening of total SLEDAI-2K score from baseline; 4) ≤ 10% deterioration in PGA score; and 5) no treatment failure. The PGA is measured on a 0 to 100 mm scale with score 0 to be No Disease Activity and score 100 to be the most Severe Disease Activity.

    Time frame: Day 210

  20. Phase 2: Number of Participants With a Cutaneous Lupus Erythematosus Area and Severity Index (CLASI) Response at Day 210

    The CLASI is a comprehensive tool for assessment of disease activity (CLASI-A) in cutaneous lupus, shown to be valid, reliable, and sensitive to changes in disease activity. Response is defined as at least 50% improvement from baseline in "A" scores. This assessment was applied to all participants as all were required to have cutaneous disease activity. The total score represents the sum of the individual scores and ranges from 0 to 70. Higher scores are awarded for more severe manifestations.

    Time frame: Day 210

  21. Phase 2: Number of Participants With Medication Failures

    Effect of BOS161721 compared with placebo for response on clinical indicators of SLE activity was assessed in adult participants with moderate to severe SLE on limited background standard of care treatment.

    Time frame: Days 30, 60, 90, 120, 150, 180, and 210

  22. Phase 2: Mean Change From Baseline in CLASI at Day 210

    The CLASI is a comprehensive tool for the assessment of disease activity (CLASI-A) and damage (CLASI-B) in cutaneous lupus, shown to be valid, reliable, and sensitive to changes in disease activity. Response is defined as 50% improvement from baseline in "A" or "B" scores. This assessment was applied to all participants as all were required to have cutaneous disease activity. The total score represents the sum of the individual scores and ranges from 0 to 70 (CLASI-A) and 0 to 58 (CLASI-B). Higher scores are awarded for more severe manifestations. Change from baseline was calculated as the post-baseline value minus the baseline value.

    Time frame: Baseline, Day 210

  23. Phase 2: Mean Change From Baseline in PGA

    The PGA is used to assess Investigator's general impression on the patient's overall status of SLE disease activity via visual analogue scale (100 mm) with 0 being "very good, asymptomatic and no limitation of normal activities" with 100 mm being "most severe possible disease ever seen in all SLE patients".

    Time frame: Baseline, Day 210

  24. Phase 2: Mean Change From Baseline in the Total Number of Swollen Joints, Tender Joints, and Active Joints (Swelling and Tenderness in the Same Joint) in the American College of Rheumatology-28 (ACR-28) Joint Count

    The ACR-28 joint count evaluated the number of tender and swollen joints in the shoulder, elbow, wrist, hand, and knee joints. Joints of the feet were excluded. Change from baseline was calculated as the post-baseline value minus the baseline value.

    Time frame: Baseline, Day 210

  25. Phase 2: Mean Change From Baseline in SLEDAI-2K at Day 210

    The SLEDAI-2K is a validated instrument that measures disease activity in SLE participants at the time of the visit and in the previous 30 days. It is a global index and includes 24 clinical and laboratory variables that are weighted by the type of manifestation, but not by severity. The total score falls between 0 and 105, with higher scores representing increased disease activity. A SLEDAI -2K of 6 or more generally represents moderately to severely active disease. Change from baseline was calculated as the post-baseline value minus the baseline value.

    Time frame: Baseline, Day 210

  26. Phase 2: Mean Change From Baseline in Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index

    The SLICC/ACR damage index is a validated instrument to assess damage, defined as irreversible impairment, continuously persistent for 6 months (ascertained by clinical assessment), occurring since the onset of lupus, and it is based on a weighted scoring system. This index records damage occurring in participants with SLE regardless of cause, with demonstrated content, face, criterion, and discriminant validity. A score of 0=no damage. Total maximum score is 47 and increasing score indicates increasing disease severity.

    Time frame: Baseline; Day 180

  27. Phase 2: Time to Medication Failure

    Participants who received prohibited medications or undergo unallowable corticosteroid (CS) usage were considered "medication failures".

    Time frame: Up to Day 270

  28. Mean Percent Change in CS Administration From the Baseline Day 0 Dose Through Day 210 in Participants Receiving ≥ 7.5 mg/Day Prednisone Equivalent at Day 0

    The percent reduction in CS administration from Day 0 through Day 210 was determined based on the average daily CS usage.

    Time frame: Baseline; Day 210

  29. Phase 2: Duration of Longest SRI-4 Response

    The SRI-4 is a composite index of SLE disease improvement that consists of scores derived from SLEDAI-2K, BILAG 2004 Index and PGA. Response based on the SRI-4 is defined by: 1) ≥ 4-point reduction in the SLEDAI-2K total score; 2) no new severe disease activity (BILAG A organ score) or more than 1 new moderate organ score (BILAG B) compare with baseline; and 3) no deterioration from baseline in the PGA by ≥ 30 millimeters. The total SLEDAI-2K score falls between 0 and 105, with higher scores representing increased disease activity. The PGA is used to assess Investigator's general impression on the patient's overall status of SLE disease activity via visual analogue scale (100 mm) with 0 being "very good, asymptomatic and no limitation of normal activities" with 100 mm being "most severe possible disease ever seen in all SLE patients". The SRI-4 response in participants with moderate to severe SLE is associated with broad improvements in clinical and participant-reported outcomes.

    Time frame: Up to Day 270

  30. Phase 2: Time to First BILAG Flare (≥ 1 New or Recurrent BILAG A or > 1 New or Recurrent BILAG B) Relative to Baseline Through Day 210

    The BILAG-2004 index is an organ-specific 97-question assessment based on the principle of the doctor's intent to treat. Only clinical features attributable to SLE disease activity were recorded and based on the participant's condition in the last 4 weeks compared with the previous 4 weeks. It was scored as not present (0), improved (1), the same (2), worse (3), or new (4). Disease activity was graded separately for 9 body systems to 5 different grades (A to E) as follows: A is very active disease, B is moderate activity, C is mild stable disease, D is inactive now but previously active, and E indicates the organ was never involved. A shift from BILAG-2004 Grade A or B to a lower grade indicates a clinically relevant change in disease activity as the BILAG-2004 grades mirror the decision points for treatment interventions.

    Time frame: Baseline; Day 210

  31. Phase 2: Number of Participants With AEs

    The safety and tolerability of repeat doses of BOS161721 (120 mg) administered SC were assessed in adult participants with moderate to severe SLE on limited background standard of care treatment.

    Time frame: Up to Day 270

07

Results

Posted Mar 14, 2022

Participant flow

The study was conducted in in the United States, Georgia, Bulgaria, Hungary, Poland, Argentina, Columbia, Mexico, Romania, Ukraine, Philippines and Peru. The first participant was screened on 10 January 2018 and last participant last visit occurred on 26, November 2020.

Participant flow — Overall Study
MilestonePhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mgPhase 2: PlaceboPhase 2: BOS161721 120 mg
Started75993776
Completed55893071
Not completed201075
Withdrew: Withdrawal by subject101022
Withdrew: Phase 1b: pregnancy, phase 2: fear of covid-19 or local restrictions100023
Withdrew: Adverse event000010
Withdrew: Decision by sponsor000020

Outcome measures

PrimaryPhase 1b: Number of Participants With Adverse Events (AEs)

The safety, tolerability, and immunogenicity of repeat doses of BOS161721 (20, 60, and 120 mg) administered SC were assessed in adult participants with moderate to severe SLE on limited background standard of care treatment, in order to estimate the optimal dose.

Time frame:
Up to Day 270
Reported as:
Count of participants · Participants
Phase 1b: Number of Participants With Adverse Events (AEs)
ParticipantsPhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
Any Treatment-Emergent Adverse Events (TEAE)4278
Related TEAE1010
Serious TEAE1020
Related Serious TEAE0000
Any Common Terminology Criteria for Adverse Events (CTCAE) Grade 2 or Higher TEAE4267
Any Related CTCAE Grade 2 or Higher TEAE1000
Any CTCAE Grade 3 TEAE1120
Any Related CTCAE Grade 3 or Higher TEAE0000
Any CTCAE Grade 4 TEAE0000
TEAE Leading to Discontinuation of Study Treatment0000
Related TEAE Leading to Discontinuation of Study Treatment0000
TEAE of Special Interest0000
Related TEAE of Special Interest0000
Dose-Limiting Toxicity0000
Related Dose-Limiting Toxicity0000
TEAE Resulting in Death0000
Related TEAE Resulting in Death0000
Injection Site Reaction0000
PrimaryPhase 2: Number of Participants With an SLE Responder Index 4 (SRI-4) Response at Day 210

The SRI-4 is a composite index of SLE disease improvement that consists of scores derived from the SLE Disease Activity Index 2000 (SLEDAI-2K), the British Isles Lupus Assessment Group (BILAG) 2004 Index and the Physician's Global Assessment (PGA). Response based on the SRI-4 is defined by: 1) ≥ 4-point reduction in the SLEDAI-2K total score; 2) no new severe disease activity (BILAG A organ score) or more than 1 new moderate organ score (BILAG B) compared with baseline; and 3) no deterioration from baseline in the PGA by ≥ 30 millimeters. The SLEDAI-2K total score falls between 0 and 105, with higher scores representing increased disease activity.The SRI-4 response in participants with moderate to severe SLE is associated with broad improvements in clinical and participant-reported outcomes.

Time frame:
Day 210
Reported as:
Count of participants · Participants
Phase 2: Number of Participants With an SLE Responder Index 4 (SRI-4) Response at Day 210
ParticipantsPhase 2: PlaceboPhase 2: BOS161721 120 mg
SRI-4 Response1940
≥ 4-Point Reduction from Baseline in SLEDAI-2K Global Score1940
No New BILAG A or More than One BILAG B Organ Score Compared with Baseline2768
No Deterioration from Baseline in PGA by >=30mm2768
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.8434 · Observed difference vs. placebo: 2.0 · 90% CI -14.5 to 18.5
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.8434 · Observed difference vs. placebo: 2.0 · 90% CI -14.5 to 18.5
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.0141 · Observed difference vs. placebo: 17.7 · 90% CI 4.5 to 30.9
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.0141 · Observed difference vs. placebo: 17.7 · 90% CI 4.5 to 30.9
SecondaryPhase 1b: Maximum Observed Concentration (Cmax)

The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

Time frame:
Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180
Reported as:
Geometric mean · ng/mL
Phase 1b: Maximum Observed Concentration (Cmax)
ng/mLPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
Dose 11160 ± 42.04610 ± 54.85500 ± 52.3
Dose 21240 ± 23.95670 ± 35.77580 ± 45.1
Dose 72580 ± 19.17820 ± 14420300 ± 37.1
SecondaryPhase 1b: First Time to Maximum Concentration (Tmax)

The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

Time frame:
Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180
Reported as:
Median · Day
Phase 1b: First Time to Maximum Concentration (Tmax)
DayPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
Dose 17.01 (6.99 to 12.00)7.00 (5.93 to 15.00)8.04 (6.95 to 17.04)
Dose 21.04 (1.00 to 29.02)1.00 (0.99 to 34.97)1.00 (1.00 to 33.03)
Dose 76.18 (5.03 to 20.04)3.55 (0.91 to 12.00)8.96 (1.00 to 28.06)
SecondaryPhase 1b: The Area Under the Plasma Concentration Versus Time Curve, From Time 0 to the Last Quantifiable Concentration (AUClast)

The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

Time frame:
Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180
Reported as:
Geometric mean · day*ng/mL
Phase 1b: The Area Under the Plasma Concentration Versus Time Curve, From Time 0 to the Last Quantifiable Concentration (AUClast)
day*ng/mLPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
Dose 125100 ± 40.489400 ± 51.7124000 ± 40.5
Dose 233600 ± 18.2147000 ± 29.7229000 ± 47.9
Dose 7155000 ± 17.9460000 ± 1731400000 ± 38.7
SecondaryPhase 1b: Terminal Elimination Half-life (t1/2)

The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

Time frame:
Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180
Reported as:
Geometric mean · Day
Phase 1b: Terminal Elimination Half-life (t1/2)
DayPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
Phase 1b: Terminal Elimination Half-life (t1/2)75.2 ± 19.966.3 ± 35.464.3 ± NA
SecondaryPhase 1b: Apparent Plasma Clearance After Extravascular Administration (CL/F)

The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

Time frame:
Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180
Reported as:
Geometric mean · Liter/day
Phase 1b: Apparent Plasma Clearance After Extravascular Administration (CL/F)
Liter/dayPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
Phase 1b: Apparent Plasma Clearance After Extravascular Administration (CL/F)0.289 ± 18.30.311 ± 1790.218 ± 38.8
SecondaryPhase 1b: Apparent Volume of Distribution After Extravascular Administration (Vz/F)

The PK of BOS161721 was characterized and the optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

Time frame:
Pre-dose: Days 0, 30, 60, 90, 120, 150, and 180. Post-dose: Days 0, 7, 15, 30, 180, 187, 195, 210, 240, and 270. Post-dose samples were collected at 4, 8, and 24 hours after study drug administration on Days 0, 30, and 180
Reported as:
Geometric mean · Liter
Phase 1b: Apparent Volume of Distribution After Extravascular Administration (Vz/F)
LiterPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
Phase 1b: Apparent Volume of Distribution After Extravascular Administration (Vz/F)31.4 ± 33.218.5 ± 39.623.0 ± NA
SecondaryPhase 1b: Mean Change From Baseline in Phosphorylated Signal Transducer and Activator of Transcription 3 (pSTAT3)

The optimal dose of BOS161721 was selected based on safety, tolerability, PK and pharmacodynamic (PD) data in participants with moderate to severe SLE.

Time frame:
Baseline (Day 0); Days 30, 44, 60, and 90 (pre-dose [trough] samples only)
Reported as:
Mean · Percentage
Phase 1b: Mean Change From Baseline in Phosphorylated Signal Transducer and Activator of Transcription 3 (pSTAT3)
PercentagePhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
% pSTAT3+ Lymphocytes - Stimulated, Day 3012.72 ± 25.172-41.80 ± 24.631-31.35 ± 20.281-25.73 ± 20.895
% pSTAT3+ Lymphocytes - Stimulated, Day 4418.45 ± 24.025-60.00 ± 19.672-32.99 ± 19.899-26.57 ± 20.856
% pSTAT3+ Lymphocytes - Stimulated, Day 60-1.48 ± 19.129-59.46 ± 20.310-32.68 ± 19.214-25.91 ± 20.850
% pSTAT3+ Lymphocytes - Stimulated, Day 90-15.94 ± 34.757-67.48 ± 15.630-33.03 ± 19.637-26.74 ± 20.962
SecondaryPhase 1b: Mean Change From Baseline in Complement 3 (C3) and Complement (C4) Levels

The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

Time frame:
Baseline (Day 0); Day 210
Reported as:
Mean · gram/Litre
Phase 1b: Mean Change From Baseline in Complement 3 (C3) and Complement (C4) Levels
gram/LitrePhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
C3, Day 2100.094 ± 0.2289-0.032 ± 0.08760.050 ± 0.3424-0.078 ± 0.2879
C4, Day 2100.024 ± 0.0391-0.038 ± 0.0370-0.007 ± 0.0783-0.024 ± 0.0410
SecondaryPhase 1b: Mean Change From Baseline in Leukocyte Immunophenotype

The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

Time frame:
Baseline (Day 0); Day 180
Reported as:
Mean · Change in percentage of cells
Phase 1b: Mean Change From Baseline in Leukocyte Immunophenotype
Change in percentage of cellsPhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
CD19+% of CD45+ Lymphocytes-2.07 ± 3.201-5.34 ± 4.663-0.39 ± 4.2010.27 ± 3.481
CD25+CD127-% of CD4+CD8--1.03 ± 1.388-0.22 ± 2.406-0.38 ± 1.495-1.08 ± 2.266
CD4+CD8-% of CD3+-1.01 ± 10.866-3.08 ± 5.2720.88 ± 7.434-5.04 ± 7.671
CD56+% OF CD45+ Lymphocytes-0.56 ± 2.093-5.76 ± 4.231-2.38 ± 2.4612.04 ± 7.984
CD8+CD4-% of CD3+-3.00 ± 7.792-1.38 ± 4.467-2.92 ± 5.010-0.24 ± 6.517
CXCR5+% of CD25+CD127-0.20 ± 4.6767.02 ± 3.37110.62 ± 11.9630.63 ± 5.915
CXCR5+% of CD4+CD8-0.81 ± 12.37315.18 ± 7.56413.14 ± 16.091-0.69 ± 7.208
ICOS+% of CD25+CD127-8.59 ± 10.6181.56 ± 3.84012.93 ± 11.9054.27 ± 17.059
ICOS+% of CD4+CD8-3.93 ± 6.9060.14 ± 5.2275.01 ± 5.0530.54 ± 15.534
IgD+C27-% of CD19+0.20 ± 7.1272.42 ± 5.882-1.07 ± 4.748-0.80 ± 6.031
IgD+CD27+% of CD19+1.29 ± 1.785-3.24 ± 6.080-1.24 ± 2.8231.00 ± 3.260
IgD+CD27-CD38++CD24++% of CD19+0.50 ± 1.2620.56 ± 1.688-0.42 ± 2.3510.16 ± 1.385
IgD-CD27+% of CD19+-0.21 ± 3.866-0.48 ± 3.8912.02 ± 3.7510.70 ± 3.740
IgD-CD27+CD38++CD138+% of CD19+0.03 ± 0.0490.04 ± 0.0890.08 ± 0.172-0.02 ± 0.130
IgD-CD27+CD38++CD138-% of CD19+-0.20 ± 0.432-0.20 ± 0.3540.59 ± 1.437-0.63 ± 1.081
IgD-CD27-% of CD19+-1.29 ± 2.9631.36 ± 2.3730.32 ± 2.059-0.83 ± 1.648
PD-1+% of CD25+CD127-0.31 ± 6.0933.30 ± 5.0397.41 ± 6.064-8.49 ± 13.258
PD-1+% of CD4+CD8--0.07 ± 6.3664.14 ± 4.1466.39 ± 5.882-9.01 ± 13.036
SecondaryPhase 1b: Mean Change From Baseline in Anti-double-stranded DNA (dsDNA) Autoantibodies at Each Visit

The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE..

Time frame:
Baseline (Day 0); Days 30, 60, 90, 120, 150, 180, 210, 240, and 270
Reported as:
Mean · International units per millilitre
Phase 1b: Mean Change From Baseline in Anti-double-stranded DNA (dsDNA) Autoantibodies at Each Visit
International units per millilitrePhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
Day 30-1.11 ± 3.5040.48 ± 0.4105.34 ± 9.053-11.51 ± 32.444
Day 60-1.81 ± 5.0480.40 ± 0.3768.06 ± 18.430-6.11 ± 15.612
Day 900.15 ± 0.4480.00 ± 0.18719.31 ± 48.594-13.44 ± 35.152
Day 120-0.02 ± 0.2700.41 ± 0.59812.30 ± 35.583-15.58 ± 47.248
Day 150-0.03 ± 0.1990.62 ± 0.70917.39 ± 50.086-11.18 ± 38.152
Day 180-2.13 ± 5.9050.52 ± 0.5848.00 ± 21.169-17.13 ± 49.897
Day 2100.05 ± 0.3590.07 ± 0.5406.76 ± 20.173-17.96 ± 50.274
Day 2400.07 ± 0.4280.34 ± 1.1176.81 ± 21.903-18.35 ± 47.898
Day 270-1.94 ± 4.9740.37 ± 0.7007.99 ± 24.116-9.71 ± 27.833
SecondaryPhase 1b: Mean Change From Baseline in Anti-Sjögren's Syndrome A and B (SSA, SSB)

The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in subjects with moderate to severe SLE.

Time frame:
Baseline (Day 0); Day 180
Reported as:
Mean · U/mL
Phase 1b: Mean Change From Baseline in Anti-Sjögren's Syndrome A and B (SSA, SSB)
U/mLPhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
La Antibody0.04 ± 0.1750.11 ± 0.1081.02 ± 2.6390.47 ± 1.668
Sjogrens SS-A52 Antibody-0.04 ± 0.1280.05 ± 0.1120.19 ± 0.567-2.25 ± 4.861
Sjogrens SS-A60 Antibody0.00 ± 0.0000.00 ± 0.000-2.62 ± 7.867-4.36 ± 8.684
SecondaryPhase 1b: Mean Change From Baseline in Anti-Smith Antibody (Sm)

The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in subjects with moderate to severe SLE.

Time frame:
Baseline (Day 0); Day 180
Reported as:
Mean · U/mL
Phase 1b: Mean Change From Baseline in Anti-Smith Antibody (Sm)
U/mLPhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
Phase 1b: Mean Change From Baseline in Anti-Smith Antibody (Sm)-1.87 ± 4.8270.74 ± 0.391-3.21 ± 9.4193.61 ± 19.504
SecondaryPhase 1b: Mean Change From Baseline in Antiphospholipid (APL) Autoantibodies (Beta 2 Glycoprotein, Cardiolipin IgG)

The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

Time frame:
Baseline (Day 0); Day 180
Reported as:
Mean · U/mL
Phase 1b: Mean Change From Baseline in Antiphospholipid (APL) Autoantibodies (Beta 2 Glycoprotein, Cardiolipin IgG)
U/mLPhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mg
Anti-Cardiolipin IgG Antibody-0.03 ± 0.4123.55 ± 5.5590.07 ± 0.585-0.42 ± 0.180
Beta-2 Glycoprotein 1 IgG Antibody-0.11 ± 0.358-7.48 ± 23.684-0.14 ± 0.8820.02 ± 0.787
SecondaryPhase 1b: Mean Change From Baseline in Abrogation of IL-21 Gene Signature

The optimal dose of BOS161721 was selected based on safety, tolerability, PK and PD data in participants with moderate to severe SLE.

Time frame:
Baseline (Day 0); Days 15, 90, 180, and 270

No measurements were reported for this outcome.

SecondaryPhase 2: Number of Participants With an SRI-4, SRI-5, and SRI-6 Response at Each Visit

The SRI-4 is a composite index of SLE disease improvement that consists of scores derived from the SLE Disease Activity Index 2000 (SLEDAI-2K) and the British Isles Lupus Assessment Group (BILAG) 2004 Index. Response based on the SRI-4 is defined by: 1) ≥ 4-point reduction in the SLEDAI-2K global score; 2) no new severe disease activity (BILAG A organ score) or more than 1 new moderate organ score (BILAG B); and 3) no deterioration from baseline in the Physician's Global Assessment (PGA) by ≥ 30 millimeters. The SRI-4 response in participants with moderate to severe SLE is associated with broad improvements in clinical and participant-reported outcomes. SRI-5 and SRI-6 are composite indices of SLE disease improvement that consist of scores derived from the SLEDAI-2K and the BILAG 2004 Index. The SRI-5 and SRI-6 are computed with a minimal five-point or six-point improvement in SLEDAI-2K being required, respectively.

Time frame:
Days 30, 60, 90, 120, 150, 180, 210, 240, and 270
Reported as:
Count of participants · Participants
Phase 2: Number of Participants With an SRI-4, SRI-5, and SRI-6 Response at Each Visit
ParticipantsPhase 2: PlaceboPhase 2: BOS161721 120 mg
SRI-4, Day 3050
SRI-4, Day 601115
SRI-4, Day 901524
SRI-4, Day 1201729
SRI-4, Day 1501935
SRI-4, Day 1802037
SRI-4, Day 2101940
SRI-5, Day 3020
SRI-5, Day 60110
SRI-5, Day 90315
SRI-5, Day 120815
SRI-5, Day 1501522
SRI-5, Day 1801429
SRI-5, Day 2101729
SRI-6, Day 3010
SRI-6, Day 60110
SRI-6, Day 90315
SRI-6, Day 120814
SRI-6, Day 1501522
SRI-6, Day 1801428
SRI-6, Day 2101729
SecondaryPhase 2: Number of Participants With a Sustained Reduction From Baseline of Oral Corticosteroid (CS) (≤ 7.5 mg/Day and < Day 0 Dose) Between Day 150 and Day 210

Effect of BOS161721 compared with placebo for response on clinical indicators of SLE activity was assessed in adult participants with moderate to severe SLE on limited background standard of care treatment.

Time frame:
Day 150 to Day 210
Reported as:
Count of participants · Participants
Phase 2: Number of Participants With a Sustained Reduction From Baseline of Oral Corticosteroid (CS) (≤ 7.5 mg/Day and < Day 0 Dose) Between Day 150 and Day 210
ParticipantsPhase 2: PlaceboPhase 2: BOS161721 120 mg
Phase 2: Number of Participants With a Sustained Reduction From Baseline of Oral Corticosteroid (CS) (≤ 7.5 mg/Day and < Day 0 Dose) Between Day 150 and Day 210717
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.7985 · Observed difference vs. placebo: -2.6 · 90% CI -19.8 to 14.5
SecondaryPhase 2: Number of Participants With New or Recurrent BILAG Flares (≥ 1 Qualifying BILAG A or > 1 Qualifying BILAG B) Through Day 210

The BILAG-2004 index is an organ-specific 97-question assessment based on the principle of the doctor's intent to treat. Only clinical features attributable to SLE disease activity were recorded and based on the participant's condition in the last 4 weeks compared with the previous 4 weeks. It was scored as not present (0), improved (1), the same (2), worse (3), or new (4). Disease activity was graded separately for 9 body systems to 5 different grades (A to E) as follows: A is very active disease, B is moderate activity, C is mild stable disease, D is inactive now but previously active, and E indicates the organ was never involved. A shift from BILAG-2004 Grade A or B to a lower grade indicates a clinically relevant change in disease activity as the BILAG-2004 grades mirror the decision points for treatment interventions.

Time frame:
Days 30, 60, 90, 120, 150, 180, 210
Reported as:
Count of participants · Participants
Phase 2: Number of Participants With New or Recurrent BILAG Flares (≥ 1 Qualifying BILAG A or > 1 Qualifying BILAG B) Through Day 210
ParticipantsPhase 2: PlaceboPhase 2: BOS161721 120 mg
Overall67
Day 3012
Day 6000
Day 9020
Day 12010
Day 15001
Day 18013
Day 21001
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.3498 · Observed difference vs. placebo: -6.9 · 90% CI -22.9 to 9.8
SecondaryPhase 2: Number of Participants With Physician's Global Assessment (PGA) Worsening

The PGA is used to assess Investigator's general impression on the patient's overall status of SLE disease activity via visual analogue scale (100 mm) with 0 being "very good, asymptomatic and no limitation of normal activities" with 100 mm being "most severe possible disease ever seen in all SLE patients". PGA worsening is defined as an increase of ≥ 30 mm from baseline.

Time frame:
Days 30, 60, 90, 120, 150, 180, and 210
Reported as:
Count of participants · Participants
Phase 2: Number of Participants With Physician's Global Assessment (PGA) Worsening
ParticipantsPhase 2: PlaceboPhase 2: BOS161721 120 mg
Overall1310
Day 210107
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.0072 · Observed difference vs. placebo: -21.8 · 90% CI -36.2 to -7.4
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.0141 · Observed difference vs. placebo: -17.7 · 90% CI -30.9 to -4.5
SecondaryPhase 2: Number of Participants With a BILAG-based Composite Lupus Assessment (BICLA) Response at Day 210

The BICLA is a responder index developed to measure response to therapy, and it includes scores from the BILAG, SLEDAI-2K, and Physician's Global Assessment (PGA). BICLA response is defined as: 1) at least 1 gradation of improvement in baseline BILAG 2004 scores in all body systems with moderate disease activity at entry (eg, all B \[moderate disease\] scores falling to C \[mild\], or D \[no activity\]); 2) no new BILAG A or more than 1 new BILAG B scores; 3) no worsening of total SLEDAI-2K score from baseline; 4) ≤ 10% deterioration in PGA score; and 5) no treatment failure. The PGA is measured on a 0 to 100 mm scale with score 0 to be No Disease Activity and score 100 to be the most Severe Disease Activity.

Time frame:
Day 210
Reported as:
Count of participants · Participants
Phase 2: Number of Participants With a BILAG-based Composite Lupus Assessment (BICLA) Response at Day 210
ParticipantsPhase 2: PlaceboPhase 2: BOS161721 120 mg
Phase 2: Number of Participants With a BILAG-based Composite Lupus Assessment (BICLA) Response at Day 2101228
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.6107 · Observed difference vs. placebo: 4.9 · 90% CI -10.7 to 20.5
SecondaryPhase 2: Number of Participants With a Cutaneous Lupus Erythematosus Area and Severity Index (CLASI) Response at Day 210

The CLASI is a comprehensive tool for assessment of disease activity (CLASI-A) in cutaneous lupus, shown to be valid, reliable, and sensitive to changes in disease activity. Response is defined as at least 50% improvement from baseline in "A" scores. This assessment was applied to all participants as all were required to have cutaneous disease activity. The total score represents the sum of the individual scores and ranges from 0 to 70. Higher scores are awarded for more severe manifestations.

Time frame:
Day 210
Reported as:
Count of participants · Participants
Phase 2: Number of Participants With a Cutaneous Lupus Erythematosus Area and Severity Index (CLASI) Response at Day 210
ParticipantsPhase 2: PlaceboPhase 2: BOS161721 120 mg
Phase 2: Number of Participants With a Cutaneous Lupus Erythematosus Area and Severity Index (CLASI) Response at Day 2101644
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.1237 · Observed difference vs. placebo: 15.4 · 90% CI -0.9 to 31.8
SecondaryPhase 2: Number of Participants With Medication Failures

Effect of BOS161721 compared with placebo for response on clinical indicators of SLE activity was assessed in adult participants with moderate to severe SLE on limited background standard of care treatment.

Time frame:
Days 30, 60, 90, 120, 150, 180, and 210
Reported as:
Count of participants · Participants
Phase 2: Number of Participants With Medication Failures
ParticipantsPhase 2: PlaceboPhase 2: BOS161721 120 mg
Overall98
Day 21075
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.0581 · Observed difference vs. placebo: -13.7 · 90% CI -26.7 to -0.7
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Pearson's chi-square test · p = 0.0471 · Observed difference vs. placebo: -14.3 · 90% CI -31.2 to 3.2
SecondaryPhase 2: Mean Change From Baseline in CLASI at Day 210

The CLASI is a comprehensive tool for the assessment of disease activity (CLASI-A) and damage (CLASI-B) in cutaneous lupus, shown to be valid, reliable, and sensitive to changes in disease activity. Response is defined as 50% improvement from baseline in "A" or "B" scores. This assessment was applied to all participants as all were required to have cutaneous disease activity. The total score represents the sum of the individual scores and ranges from 0 to 70 (CLASI-A) and 0 to 58 (CLASI-B). Higher scores are awarded for more severe manifestations. Change from baseline was calculated as the post-baseline value minus the baseline value.

Time frame:
Baseline, Day 210
Reported as:
Mean · score on a scale
Phase 2: Mean Change From Baseline in CLASI at Day 210
score on a scalePhase 2: PlaceboPhase 2: BOS161721 120 mg
CLASI-A (Total Activity)-4.8 ± 4.08-5.2 ± 4.62
CLASI-B (Total Damage)-0.6 ± 2.61-0.2 ± 0.90
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · ANCOVA · p = 0.6596 · Treatment difference (bos161721-placebo): -0.3 · 90% CI -1.63 to 0.94This is based on LS Means
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · ANCOVA · p = 0.4105 · Treatment difference (bos161721-placebo): 0.3 · 90% CI -0.27 to 0.81This is based on LS Means
SecondaryPhase 2: Mean Change From Baseline in PGA

The PGA is used to assess Investigator's general impression on the patient's overall status of SLE disease activity via visual analogue scale (100 mm) with 0 being "very good, asymptomatic and no limitation of normal activities" with 100 mm being "most severe possible disease ever seen in all SLE patients".

Time frame:
Baseline, Day 210
Reported as:
Mean · score on a scale
Phase 2: Mean Change From Baseline in PGA
score on a scalePhase 2: PlaceboPhase 2: BOS161721 120 mg
Phase 2: Mean Change From Baseline in PGA-29.2 ± 20.69-28.7 ± 20.35
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · ANCOVA · p = 0.8546 · Treatment difference (bos161721-placebo): 0.8 · 90% CI -6.07 to 7.58This is based on LS Means
SecondaryPhase 2: Mean Change From Baseline in the Total Number of Swollen Joints, Tender Joints, and Active Joints (Swelling and Tenderness in the Same Joint) in the American College of Rheumatology-28 (ACR-28) Joint Count

The ACR-28 joint count evaluated the number of tender and swollen joints in the shoulder, elbow, wrist, hand, and knee joints. Joints of the feet were excluded. Change from baseline was calculated as the post-baseline value minus the baseline value.

Time frame:
Baseline, Day 210
Reported as:
Mean · Number of swollen/tender/active joints
Phase 2: Mean Change From Baseline in the Total Number of Swollen Joints, Tender Joints, and Active Joints (Swelling and Tenderness in the Same Joint) in the American College of Rheumatology-28 (ACR-28) Joint Count
Number of swollen/tender/active jointsPhase 2: PlaceboPhase 2: BOS161721 120 mg
Sum of Swelling-6.8 ± 5.17-5.9 ± 5.05
Sum of Tenderness-8.3 ± 7.00-7.2 ± 5.57
Sum of Active Joints-6.5 ± 5.54-5.6 ± 4.65
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · ANCOVA · p = 0.4455 · Treatment difference (bos161721-placebo): 0.5 · 90% CI -0.63 to 1.71This is based on LS Means
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · ANCOVA · p = 0.3367 · Treatment difference (bos161721-placebo): 0.9 · 90% CI -0.65 to 2.47This is based on LS Means
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · ANCOVA · p = 0.2550 · Treatment difference (bos161721-placebo): 0.8 · 90% CI -0.34 to 1.86This is based on LS Means
SecondaryPhase 2: Mean Change From Baseline in SLEDAI-2K at Day 210

The SLEDAI-2K is a validated instrument that measures disease activity in SLE participants at the time of the visit and in the previous 30 days. It is a global index and includes 24 clinical and laboratory variables that are weighted by the type of manifestation, but not by severity. The total score falls between 0 and 105, with higher scores representing increased disease activity. A SLEDAI -2K of 6 or more generally represents moderately to severely active disease. Change from baseline was calculated as the post-baseline value minus the baseline value.

Time frame:
Baseline, Day 210
Reported as:
Mean · score on a scale
Phase 2: Mean Change From Baseline in SLEDAI-2K at Day 210
score on a scalePhase 2: PlaceboPhase 2: BOS161721 120 mg
Phase 2: Mean Change From Baseline in SLEDAI-2K at Day 210-4.7 ± 3.71-3.9 ± 3.31
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · ANCOVA · p = 0.2498 · Treatment difference (bos161721-placebo): 0.8 · 90% CI -0.34 to 1.93This is based on LS Means
SecondaryPhase 2: Mean Change From Baseline in Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index

The SLICC/ACR damage index is a validated instrument to assess damage, defined as irreversible impairment, continuously persistent for 6 months (ascertained by clinical assessment), occurring since the onset of lupus, and it is based on a weighted scoring system. This index records damage occurring in participants with SLE regardless of cause, with demonstrated content, face, criterion, and discriminant validity. A score of 0=no damage. Total maximum score is 47 and increasing score indicates increasing disease severity.

Time frame:
Baseline; Day 180
Reported as:
Mean · score on a scale
Phase 2: Mean Change From Baseline in Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index
score on a scalePhase 2: PlaceboPhase 2: BOS161721 120 mg
Phase 2: Mean Change From Baseline in Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index0 ± 00.1 ± 0.24
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · ANCOVA · p = 0.2558 · Treatment difference (bos161721-placebo): 0.0 · 90% CI -0.02 to 0.12This is based on LS Means
SecondaryPhase 2: Time to Medication Failure

Participants who received prohibited medications or undergo unallowable corticosteroid (CS) usage were considered "medication failures".

Time frame:
Up to Day 270
Reported as:
Median · Days
Phase 2: Time to Medication Failure
DaysPhase 2: PlaceboPhase 2: BOS161721 120 mg
Phase 2: Time to Medication FailureNA (NA to NA)NA (NA to NA)
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Log Rank · p = 0.0479 · Hazard ratio (hr): 0.39 · 90% CI 0.18 to 0.88Hazard rate of BOS161721 120 mg / Hazard rate of placebo
SecondaryMean Percent Change in CS Administration From the Baseline Day 0 Dose Through Day 210 in Participants Receiving ≥ 7.5 mg/Day Prednisone Equivalent at Day 0

The percent reduction in CS administration from Day 0 through Day 210 was determined based on the average daily CS usage.

Time frame:
Baseline; Day 210
Reported as:
Mean · Percent Reduction in Dose (mg/day)
Mean Percent Change in CS Administration From the Baseline Day 0 Dose Through Day 210 in Participants Receiving ≥ 7.5 mg/Day Prednisone Equivalent at Day 0
Percent Reduction in Dose (mg/day)Phase 2: PlaceboPhase 2: BOS161721 120 mg
Mean Percent Change in CS Administration From the Baseline Day 0 Dose Through Day 210 in Participants Receiving ≥ 7.5 mg/Day Prednisone Equivalent at Day 0-36.61 ± 22.389-21.49 ± 26.950
SecondaryPhase 2: Duration of Longest SRI-4 Response

The SRI-4 is a composite index of SLE disease improvement that consists of scores derived from SLEDAI-2K, BILAG 2004 Index and PGA. Response based on the SRI-4 is defined by: 1) ≥ 4-point reduction in the SLEDAI-2K total score; 2) no new severe disease activity (BILAG A organ score) or more than 1 new moderate organ score (BILAG B) compare with baseline; and 3) no deterioration from baseline in the PGA by ≥ 30 millimeters. The total SLEDAI-2K score falls between 0 and 105, with higher scores representing increased disease activity. The PGA is used to assess Investigator's general impression on the patient's overall status of SLE disease activity via visual analogue scale (100 mm) with 0 being "very good, asymptomatic and no limitation of normal activities" with 100 mm being "most severe possible disease ever seen in all SLE patients". The SRI-4 response in participants with moderate to severe SLE is associated with broad improvements in clinical and participant-reported outcomes.

Time frame:
Up to Day 270
Reported as:
Mean · Days
Phase 2: Duration of Longest SRI-4 Response
DaysPhase 2: PlaceboPhase 2: BOS161721 120 mg
Phase 2: Duration of Longest SRI-4 Response119.8 ± 68.26124.2 ± 68.48
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · ANOVA · p = 0.7898 · Treatment difference (bos161721-placebo): 4.4 · 90% CI -22.92 to 31.70This is based on LS Means
SecondaryPhase 2: Time to First BILAG Flare (≥ 1 New or Recurrent BILAG A or > 1 New or Recurrent BILAG B) Relative to Baseline Through Day 210

The BILAG-2004 index is an organ-specific 97-question assessment based on the principle of the doctor's intent to treat. Only clinical features attributable to SLE disease activity were recorded and based on the participant's condition in the last 4 weeks compared with the previous 4 weeks. It was scored as not present (0), improved (1), the same (2), worse (3), or new (4). Disease activity was graded separately for 9 body systems to 5 different grades (A to E) as follows: A is very active disease, B is moderate activity, C is mild stable disease, D is inactive now but previously active, and E indicates the organ was never involved. A shift from BILAG-2004 Grade A or B to a lower grade indicates a clinically relevant change in disease activity as the BILAG-2004 grades mirror the decision points for treatment interventions.

Time frame:
Baseline; Day 210
Reported as:
Median · Days
Phase 2: Time to First BILAG Flare (≥ 1 New or Recurrent BILAG A or > 1 New or Recurrent BILAG B) Relative to Baseline Through Day 210
DaysPhase 2: PlaceboPhase 2: BOS161721 120 mg
Phase 2: Time to First BILAG Flare (≥ 1 New or Recurrent BILAG A or > 1 New or Recurrent BILAG B) Relative to Baseline Through Day 210NA (NA to NA)NA (NA to NA)
Statistical analysis
  • Phase 2: Placebo vs Phase 2: BOS161721 120 mg · Log-Rank Test (2-Sided) · p = 0.0083 · Hazard ratio (hr): 0.33 · 90% CI 0.16 to 0.68Hazard rate of BOS161721 120mg / Hazard rate of placebo
SecondaryPhase 2: Number of Participants With AEs

The safety and tolerability of repeat doses of BOS161721 (120 mg) administered SC were assessed in adult participants with moderate to severe SLE on limited background standard of care treatment.

Time frame:
Up to Day 270
Reported as:
Count of participants · Participants
Phase 2: Number of Participants With AEs
ParticipantsPhase 2: PlaceboPhase 2: BOS161721 120 mg
Any TEAE2344
Related TEAE48
Serious TEAE32
Related Serious TEAE00
Any CTCAE Grade 2 or Higher TEAE1625
Any Related CTCAE Grade 2 or Higher TEAE03
Any CTCAE Grade 3 TEAE36
Any Related CTCAE Grade 3 or Higher TEAE00
Any CTCAE Grade 4 TEAE00
Any Related CTCAE Grade 4 TEAE00
TEAE Leading to Discontinuation of Study Treatment10
Related TEAE Leading to Discontinuation of Study Treatment00
TEAE of Special Interest01
Related TEAE of Special Interest00
Dose-Limiting Toxicity00
Related Dose-Limiting Toxicity00
TEAE Resulting in Death00
Related TEAE Resulting in Death00
Injection Site Reaction11

Adverse events

Collected over Up to Day 270. Non-serious events are listed at a 5% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Phase 1b: Placebo0/7 (0%)1/7 (14.3%)4/7 (57.1%)
Phase 1b: Cohort 1: BOS161721 20 mg0/5 (0%)0/5 (0%)2/5 (40%)
Phase 1b: Cohort 2: BOS161721 60 mg0/9 (0%)2/9 (22.2%)7/9 (77.8%)
Phase 1b: Cohort 3: BOS161721 120 mg0/9 (0%)0/9 (0%)8/9 (88.9%)
Phase 2: Placebo0/37 (0%)3/37 (8.1%)22/37 (59.5%)
Phase 2: BOS161721 120 mg0/76 (0%)2/76 (2.6%)44/76 (57.9%)
Most frequent serious events
Showing 10 of 11
Most frequent serious events
EventPhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mgPhase 2: PlaceboPhase 2: BOS161721 120 mg
ExomphalosCongenital, familial and genetic disorders1/70/50/90/90/370/76
Chronic Obstructive Pulmonary DiseaseRespiratory, thoracic and mediastinal disorders0/70/51/90/90/370/76
Basal Cell CarcinomaNeoplasms benign, malignant and unspecified (incl cysts and polyps)0/70/51/90/90/370/76
Squamous Cell Carcinoma of SkinNeoplasms benign, malignant and unspecified (incl cysts and polyps)0/70/51/90/90/370/76
Acute Respiratory FailureRespiratory, thoracic and mediastinal disorders0/70/50/90/91/370/76
AsthmaRespiratory, thoracic and mediastinal disorders0/70/50/90/91/370/76
Lupus PneumonitisRespiratory, thoracic and mediastinal disorders0/70/50/90/91/370/76
AnaemiaBlood and lymphatic system disorders0/70/50/90/91/370/76
Biliary ColicHepatobiliary disorders0/70/50/90/91/370/76
Intraductal Proliferative Breast LesionNeoplasms benign, malignant and unspecified (incl cysts and polyps)0/70/50/90/90/371/76
Most frequent other events
Showing 10 of 60
Most frequent other events
EventPhase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mgPhase 2: PlaceboPhase 2: BOS161721 120 mg
NauseaGastrointestinal disorders1/70/51/92/91/374/76
Non-Cardiac Chest PainGeneral disorders0/70/50/92/91/370/76
Upper Respiratory Tract InfectionInfections and infestations1/70/50/92/91/370/76
Urinary Tract InfectionInfections and infestations0/71/50/90/94/374/76
PharyngitisInfections and infestations0/71/50/90/92/374/76
Otitis Media AcuteInfections and infestations0/71/50/90/90/370/76
Weight IncreasedInvestigations0/71/50/90/91/370/76
Sjogren's SyndromeMusculoskeletal and connective tissue disorders0/71/50/90/91/370/76
HeadacheNervous system disorders0/71/50/90/92/374/76
Confusional StatePsychiatric disorders0/71/50/90/90/370/76

Baseline characteristics

Age, Continuous
Age, Continuous(years)Phase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mgPhase 2: PlaceboPhase 2: BOS161721 120 mgTotal
Placebo48.1 ± 17.67———45.7 ± 12.52—46.1 ± 13.25
BOS161721—50.0 ± 8.5149.3 ± 11.3147.3 ± 10.43—44.5 ± 12.5245.5 ± 12.07
Sex: Female, Male
Sex: Female, Male(Participants)Phase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mgPhase 2: PlaceboPhase 2: BOS161721 120 mgTotal
Female75883669133
Male00111710
Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)Phase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mgPhase 2: PlaceboPhase 2: BOS161721 120 mgTotal
Hispanic or Latino1120173253
Not Hispanic or Latino6479204490
Unknown or Not Reported0000000
Race (NIH/OMB)
Race (NIH/OMB)(Participants)Phase 1b: PlaceboPhase 1b: Cohort 1: BOS161721 20 mgPhase 1b: Cohort 2: BOS161721 60 mgPhase 1b: Cohort 3: BOS161721 120 mgPhase 2: PlaceboPhase 2: BOS161721 120 mgTotal
American Indian or Alaska Native0000000
Asian0000000
Native Hawaiian or Other Pacific Islander0000000
Black or African American20036718
White5596204590
More than one race0000112435
Unknown or Not Reported0000000
08

Study locations

68 sites
  • Pinnacle Research Group
    Anniston, Alabama 36207, United States
  • TriWest Research Associates
    El Cajon, California 92020-4124, United States
  • Valerius Medical Group and Research Center
    Los Alamitos, California 90720-5403, United States
  • Westlake Medical Research
    Thousand Oaks, California 91360-3994, United States
  • Clinical Research of West Florida
    Clearwater, Florida 33765-2616, United States
  • Omega Research Consultants
    DeBary, Florida 32713-2260, United States
  • Centre for Rheumatology Immunology and Arthritis
    Fort Lauderdale, Florida 33309-1715, United States
  • Millennium Research
    Ormond Beach, Florida 32174, United States
  • The Arthritis Center
    Palm Harbor, Florida 34684, United States
  • Clinical Research of West Florida
    Tampa, Florida 33603, United States
  • Clinic of Robert Hozman/Clinical Investigation Specialists, Inc.
    Skokie, Illinois 60076-1238, United States
  • Indiana University School of Medicine
    Indianapolis, Indiana 46202, United States
  • Aa Mrc Llc
    Grand Blanc, Michigan 48439, United States
  • June DO PC
    Lansing, Michigan 48910-8595, United States
  • Joint and Muscle Research Institute
    Charlotte, North Carolina 28204-3130, United States
  • Ramesh C. Gupta M.D.
    Memphis, Tennessee 38119-5214, United States
  • Accurate Clinical Research Inc
    Houston, Texas 77089, United States
  • Hospital Militar Central - Servicio de Reumatología
    Buenos Aires, C1426BOR, Argentina
  • Framingham Centro Medico
    La Plata, B1902COS, Argentina
  • Centro Medico Privado de Reumatologia
    San Miguel de Tucumán, T4000AXL, Argentina
  • Centro de Investigaciones Reumatologicas
    San Miguel de Tucumán, T4000BRD, Argentina
  • Diagnostic Consultative Center Sveti Georgi EOOD
    Plovdiv, 4000, Bulgaria
  • University Multiprofile Hospital for Active Treatment Plovdiv
    Plovdiv, 4001, Bulgaria
  • Medical Center - 1 - Sevlievo EOOD
    Sevlievo, 5400, Bulgaria
  • Centro Integral de Reumatologia del Caribe CIRCARIBE S.A.S
    Barranquilla, 080002, Colombia
  • Preventive Care S.A.S.
    Bogotá, 110311, Colombia
  • Medicity S.A.S.
    Bucaramanga, 680003, Colombia
  • Servimed S.A.S.
    Bucaramanga, 680003, Colombia
  • Clinica de Artritis Temprana
    Cali, 760043, Colombia
  • Hospital Pablo Tobon Uribe
    Medellín, 050034, Colombia
  • V. Tsitlanadze Scientifically-Practical Rheumatology Center Ltd
    Tbilisi, 0102, Georgia
  • Research Institute of Clinical Medicine Ltd
    Tbilisi, 0112, Georgia
  • LTD New Hospitals
    Tbilisi, 0114, Georgia
  • Mtskheta Street Clinic Ltd
    Tbilisi, 0179, Georgia
  • First Medical Center
    Tbilisi, 0180, Georgia
  • Multiprofile Clinic Consilium Medulla Ltd
    Tbilisi, 0186, Georgia
  • Qualiclinic Kft.
    Budapest, 1036, Hungary
  • DE Klinikai Központ
    Debrecen, 4032, Hungary
  • Békés Megyei Központi Kórház Pándy Kálmán Tagkórház
    Gyula, 5700, Hungary
  • Centro Integral en Reumatología S.A. de C.V. (CIRSA)
    Guadalajara, 44160, Mexico
  • Hospital Civil de Guadalajara Fray Antonio Alcalde
    Guadalajara, 44280, Mexico
  • CLIDITER S.A. de C.V. (Centro de Investigación y Tratamiento de las Enfermedades Reumaticas)
    Mexico City, 06700, Mexico
  • Hogar Clinica San Juan De Dios
    Cayma, 04000, Peru
  • Centro de Investigación Clínica Trujillo E.I.R.L.
    La Libertad, 13001, Peru
  • Hospital Nacional Cayetano Heredia
    Lima, 15102, Peru
  • Clinica San Juan Bautista
    Lima, 15431, Peru
  • Instituto de Ginecología y Reproducción
    Santiago de Surco, 15023, Peru
  • Angeles University Foundation Medical Center
    Angeles City, 2009, Philippines
  • Southern Philippines Medical Center
    Davao City, 8000, Philippines
  • Mary Mediatrix Medical Center
    Lipa City, 4217, Philippines
  • Philippine General Hospital
    Manila, 1000, Philippines
  • University of Santo Tomas Hospital
    Manila, 1015, Philippines
  • Centrum Kliniczno - Badawcze J. Brzezicki, B. Gronkiewicz Brzezicka Spółka Lekarska
    Elblag, 82-300, Poland
  • Centrum Medyczne Plejady
    Krakow, 30-363, Poland
  • Centrum Nowoczesnych Terapii Dobry Lekarz sp. z o.o
    Krakow, 31-011, Poland
  • Centrum Medyczne AMED oddział w Łodzi
    Lodz, 91-363, Poland
  • NZOZ Lecznica MAK-MED
    Nadarzyn, 05-830, Poland
  • Prywatna Praktyka Lekarska Prof. UM dr hab. med Pawel Hrycaj
    Poznan, 61-397, Poland
  • SANUS Szpital Specjalistyczny sp. z o.o
    Stalowa Wola, 37-450, Poland
  • Reumatika-Centrum Reumatologii
    Warsaw, 02-691, Poland
  • Centrul Medical de Diagnostic si Tratament Ambulatoriu Neomed SRL
    Brasov, 500283, Romania
  • Spitalul Clinic Judetean De Urgenta Cluj Napoca
    Cluj-Napoca, 400006, Romania
  • Spitalul Clinic de Recuperare Iasi #2
    Iași, 700661, Romania
  • National Scientific Center at Institute of Cardiology named after acad. M.D. Strazhesko
    Kyiv, 03680, Ukraine
  • Kyiv Regional Clinical Hospital
    Kyiv, 04107, Ukraine
  • Odesa Regional Clinical Hospital
    Odesa, 65025, Ukraine
  • Communal Non-Profit Enterprise "Ternopil University Clinic" of Ternopil Regional Council
    Ternopil, 46002, Ukraine
  • Vinnytsia Regional Clinical Hospital
    Vinnytsia, 21018, Ukraine
09

References and documents

Publications

  • Ahmad SB, Jefferson JA. Targeting B Cells and Plasma Cells in Glomerular Disease. J Am Soc Nephrol. 2025 Jun 4;36(9):1844-1857. doi: 10.1681/ASN.0000000772. PubMed 40465397 ↗

Study documents

  • Study protocol · Apr 30, 2020
  • Statistical analysis plan · Apr 23, 2021

Documents are hosted by the registry — open the source record to download them.

10

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Ran from Jan 2018 to primary completion in Nov 2020, 34 months.

Results were first posted in Mar 2022, 1 year 3 months after primary completion.

Of 38 phase 1/2 interventional studies under Lupus Erythematosus, Systemic, half reached primary completion within 42 months of starting (the median), counting those still running; a quarter within 21 and three quarters within 60. This study's 34 months is below that.

How these figures are worked out, and which studies are left out of them.

Registered
Dec 8, 2017
First posted
Dec 13, 2017
StartActual
Jan 10, 2018
Primary completionActual
Nov 26, 2020
CompletionActual
Nov 26, 2020
Results first posted
Mar 14, 2022
Last update
Mar 14, 2022
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Mar 14, 2022, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT03371251
Lead sponsor
Boston Pharmaceuticals
Responsible party
Sponsor
First posted
Dec 13, 2017
Start date
Jan 10, 2018
Primary completion
Nov 26, 2020
Completion
Nov 26, 2020
Results posted
Mar 14, 2022
Last update
Mar 14, 2022

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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