Hidradenitis Suppurativa Study of Izokibep

September 29, 2025 updated by: ACELYRIN Inc.

A Randomized, Double-blind, Placebo-controlled, Multicenter, Phase 3 Study to Evaluate the Efficacy and Safety of Izokibep in Subjects With Moderate to Severe Hidradenitis Suppurativa

Izokibep is a small protein molecule that acts as a selective, potent inhibitor of interleukin 17A, to which it binds with high affinity. This study investigates izokibep in participants with active Hidradenitis Suppurativa (HS), including tumor necrosis factor-alpha inhibitor (TNFi) naïve participants, and those who had an inadequate response or intolerance to TNFi, or for whom TNFi is contraindicated.

Study Overview

Status

Terminated

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

258

Phase

  • Phase 3

Contacts and Locations

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

Study Locations

  • Canada
    • Alberta
      • Edmonton, Alberta, Canada, T6G1C3
        • Clinical Research Site
      • Edmonton, Alberta, Canada, T6H4J8
        • Clinical Research Site
    • Manitoba
      • Winnipeg, Manitoba, Canada, R3M3Z4
        • Clinical Research Site
    • Ontario
      • North Bay, Ontario, Canada, P1B 3Z7
        • Clinical Research Site
      • Peterborough, Ontario, Canada, K9J5K2
        • Clinical Research Site
      • Toronto, Ontario, Canada, M2N3A6
        • Clinical Research Site
      • Toronto, Ontario, Canada, M4W2N4
        • Clinical Research Site
      • Toronto, Ontario, Canada, M5A3R6
        • Clinical Research Site
      • Waterloo, Ontario, Canada, N2J1C4
        • Clinical Research Site
    • Saskatchewan
      • Saskatoon, Saskatchewan, Canada, S7K2C1
        • Clinical Research Site
  • France
      • Toulon, France, 83000
        • Clinical Research Site
    • Bourgogne-Franche-Comté
      • Dijon, Bourgogne-Franche-Comté, France, 21000
        • Clinical Research Site
    • Occitanie
      • Montpellier, Occitanie, France, 34090
        • Clinical Research Site
    • Pays de la Loire Region
      • Nantes, Pays de la Loire Region, France, 44000
        • Clinical Research Site
  • Germany
    • Hesse
      • Darmstadt, Hesse, Germany, 64283
        • Clinical Research Site
    • Lower Saxony
      • Bad Bentheim, Lower Saxony, Germany, 48455
        • Clinical Research Site
    • Rhineland-Palatinate
      • Mainz, Rhineland-Palatinate, Germany, 55128
        • Clinical Research Site
    • Saxony
      • Leipzig, Saxony, Germany, 04103
        • Clinical Research Site
    • Schleswig-Holstein
      • Kiel, Schleswig-Holstein, Germany, 24148
        • Clinical Research Site
  • Hungary
      • Budapest, Hungary, 1036
        • Clinical Research Site
    • Hajdú-Bihar
      • Debrecen, Hajdú-Bihar, Hungary, 4032
        • Clinical Research Site
    • Zala County
      • Zalaegerszeg, Zala County, Hungary, 8900
        • Clinical Research Site
  • Japan
      • Nishinomiya, Japan, 663-8186
        • Clinical Research Site
    • Fukoka Prefecture
      • Fukuoka, Fukoka Prefecture, Japan, 814-0180
        • Clinical Research Site
    • Fukuoka
      • Kitakyushu, Fukuoka, Japan, 807-8555
        • Clinical Research Site
    • Hokkaido Prefecture
      • Obihiro, Hokkaido Prefecture, Japan, 080-0013
        • Clinical Research Site
      • Sapporo, Hokkaido Prefecture, Japan, 060-0063
        • Clinical Research Site
    • Kanagawa
      • Kawasaki, Kanagawa, Japan, 216-8511
        • Clinical Research Site
      • Yokohama, Kanagawa, Japan, 236-0004
        • Clinical Research Site
    • Kyoto
      • Kyoto, Kyoto, Japan, 602-8566
        • Clinical Research Site
    • Osaka
      • Osaka, Osaka, Japan, 589-8511
        • Clinical Research Site
    • Tokyo
      • Shinjuku-Ku, Tokyo, Japan, 160-0023
        • Clinical Research Site
      • tabashi City, Tokyo, Japan, 173-8610
        • Clinical Research Site
  • Poland
    • Lesser Poland Voivodeship
      • Krakow, Lesser Poland Voivodeship, Poland, 30-001
        • Clinical Research Site
      • Krakow, Lesser Poland Voivodeship, Poland, 90-436
        • Clinical Research Site
    • Lower Silesian Voivodeship
      • Wroclaw, Lower Silesian Voivodeship, Poland, 50-566
        • Clinical Research Site
      • Wroclaw, Lower Silesian Voivodeship, Poland, 51-318
        • Clinical Research Site
    • Lublin Voivodeship
      • Lublin, Lublin Voivodeship, Poland, 20-573
        • Clinical Research Site
    • Silesian Voivodeship
      • Katowice, Silesian Voivodeship, Poland, 40-611
        • Clinical Research Site
      • Ożarowice, Silesian Voivodeship, Poland, 42-624
        • Clinical Research Site
      • Sosnowiec, Silesian Voivodeship, Poland, 41-218
        • Clinical Research Site
    • Łódź Voivodeship
      • Lodz, Łódź Voivodeship, Poland, 90-265
        • Clinical Research Site
  • Spain
      • Madrid, Spain, 28031
        • Clinical Research Site
    • Andalusia
      • Seville, Andalusia, Spain, 41009
        • Clinical Research Site
    • Balearic Islands
      • Palma de Mallorca, Balearic Islands, Spain, 07120
        • Clinical Research Site
    • Catalonia
      • Badalona, Catalonia, Spain, 08916
        • Clinical Research Site
      • Barcelona, Catalonia, Spain, 08041
        • Clinical Research Site
    • Valencia
      • Manises, Valencia, Spain, 46940
        • Clinical Research Site
  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35233
        • Clinical Research Site
    • Arizona
      • Scottsdale, Arizona, United States, 85255
        • Clinical Research Site
      • Scottsdale, Arizona, United States, 85260
        • Clinical Research Site
    • Arkansas
      • Fayetteville, Arkansas, United States, 72703
        • Clinical Research Site
    • California
      • Encino, California, United States, 91436
        • Clinical Research Site
      • Fountain Valley, California, United States, 92708
        • Clinical Research Site
      • Fremont, California, United States, 94538
        • Clinical Research Site
      • Los Angeles, California, United States, 90045
        • Clinical Research Site
      • Santa Monica, California, United States, 90404
        • Clinical Research Site
    • Florida
      • Boca Raton, Florida, United States, 33486
        • Clinical Research Site
      • Brandon, Florida, United States, 33511
        • Clinical Research Site
      • Coral Gables, Florida, United States, 33134
        • Clinical Research Site
      • Hollywood, Florida, United States, 33021
        • Clinical Research Site
      • Tampa, Florida, United States, 33607
        • Clinical Research Site
      • Tampa, Florida, United States, 33613
        • Clinical Research Site
    • Georgia
      • Atlanta, Georgia, United States, 30315
        • Clinical Research Site
      • Sandy Springs, Georgia, United States, 30328
        • Clinical Research Site
      • Savannah, Georgia, United States, 31419
        • Clinical Research Site
    • Illinois
      • Springfield, Illinois, United States, 62702
        • Clinical Research Site
    • Indiana
      • Indianapolis, Indiana, United States, 46250
        • Clinical Research Site
      • Plainfield, Indiana, United States, 46168
        • Clinical Research Site
    • Kansas
      • Topeka, Kansas, United States, 66614
        • Clinical Research Site
    • Kentucky
      • Murray, Kentucky, United States, 42071
        • Clinical Research Site
    • Louisiana
      • Baton Rouge, Louisiana, United States, 70808
        • Clinical Research Site
      • Baton Rouge, Louisiana, United States, 70809
        • Clinical Research Site
      • New Orleans, Louisiana, United States, 70115
        • Clinical Research Site
    • Maryland
      • Largo, Maryland, United States, 20774
        • Clinical Research Site
    • Massachusetts
      • Boston, Massachusetts, United States, 02215
        • Clinical Research Site
    • Michigan
      • Canton, Michigan, United States, 48187
        • Clinical Research Site
      • Troy, Michigan, United States, 48084
        • Clinical Research Site
    • New Hampshire
      • Lebanon, New Hampshire, United States, 03766
        • Clinical Research Site
    • New York
      • New York, New York, United States, 10128
        • Clinical Research Site
    • North Carolina
      • Charlotte, North Carolina, United States, 28277
        • Clinical Research Site
    • Ohio
      • Boardman, Ohio, United States, 44512
        • Clinical Research Site
      • Mason, Ohio, United States, 45040
        • Clinical Research Site
      • Springfield, Ohio, United States, 45505
        • Clinical Research Site
    • Oregon
      • Portland, Oregon, United States, 97223
        • Clinical Research Site
    • Pennsylvania
      • Hershey, Pennsylvania, United States, 17033
        • Clinical Research Site
      • Pittsburgh, Pennsylvania, United States, 15213
        • Clinical Research Site
      • Sugarloaf, Pennsylvania, United States, 18249
        • Clinical Research Site
    • Tennessee
      • Thompson's Station, Tennessee, United States, 37179
        • Clinical Research Site
    • Texas
      • Arlington, Texas, United States, 76011
        • Clinical Research Site
      • Frisco, Texas, United States, 75034
        • Clinical Research Site
      • Pflugerville, Texas, United States, 78660
        • Clinical Research Site
      • San Antonio, Texas, United States, 78218
        • Clinical Research Site
      • The Woodlands, Texas, United States, 77380
        • Clinical Research Site
      • Webster, Texas, United States, 77598
        • Clinical Research Site
    • Utah
      • Springville, Utah, United States, 84663
        • Clinical Research Site
      • West Jordan, Utah, United States, 84088
        • Clinical Research Site
    • Virginia
      • Charlottesville, Virginia, United States, 22908
        • Clinical 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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

General

  • Participant has provided signed informed consent including consenting to comply with the requirements and restrictions listed in the informed consent form (ICF) and in protocol
  • 18 years of age or older
  • No known history of active tuberculosis unless adequately treated according to World Health Organization/Center for Disease Control and Prevention therapeutic guidance and determined to be fully recovered by a tuberculosis specialist

Type of Participant and Disease Characteristics

  • Diagnosis of HS for ≥ 6 months prior to first dose of study drug
  • Hidradenitis suppurativa lesions present in ≥ 2 distinct anatomic areas, one of which is Hurley Stage II or Hurley Stage III
  • A total AN count of ≥ 5 at screening and Day 1 prior to enrollment/randomization
  • Participant must have had an inadequate response to oral antibiotics OR exhibited recurrence after discontinuation to, OR demonstrated intolerance to, OR have a contraindication to oral antibiotics for treatment of their HS
  • Must agree to use daily or a minimum of 3 days a week over-the-counter topical antiseptics
  • Participant must be willing to complete a daily skin pain diary

Exclusion Criteria:

Medical Conditions

  • Draining fistula count of > 20
  • Outpatient surgery ≤ 8 weeks prior or inpatient surgery ≤ 12 weeks prior to enrollment/randomization
  • Other active skin disease or condition that could interfere with study assessments
  • History of active inflammatory bowel disease (IBD) OR symptoms within the last year that may be suggestive of IBD
  • Chronic pain not associated with HS
  • Uncontrolled, clinically significant system disease
  • History of demyelinating disease or neurological symptoms suggestive of demyelinating disease
  • Malignancy within 5 years
  • The participant is at risk of self-harm or harm to others
  • Active infection or history of certain infections
  • Tuberculosis or fungal infection seen on available chest x-ray taken within 3 months prior to first dose of study drug or at screening (Exception: documented evidence of completed treatment and clinically resolved)
  • Known history of human immunodeficiency virus (HIV)

Other protocol defined Inclusion/Exclusion criteria may apply

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: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Group 1
Participants will receive placebo as a subcutaneous (SC) injection every week (QW) from Day 1 to Week 15. Participants will then receive izokibep as a SC injection QW from Week 16 to Week 51.
Drug: Placebo
Solution for injection
Drug: Izokibep
Solution for injection
Experimental: Group 2
Participants will receive izokibep QW from Day 1 to Week 51.
Drug: Izokibep
Solution for injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percentage of Participants Achieving Hidradenitis Suppurativa Clinical Response 75 (HiSCR75) at Week 12
Time Frame: Week 12

The percentage of participants achieving HiSCR75 was defined as meeting all 3 criteria below:

  • ([abscess and inflammatory nodule (AN) count at baseline - AN count at current visit] / AN count at baseline) × 100% ≥ 75%
  • Abscess count at baseline ≥ abscess count at the current visit
  • Draining fistula count at baseline ≥ draining fistula count at the current visit.

HiSCR75 was evaluated using nonresponse imputation (NRI) and multiple imputation (MI) methods.
Week 12

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percentage of Participants Achieving HiSCR90 at Week 12
Time Frame: Week 12

The percentage of participants achieving HiSCR90 was defined as meeting all 3 criteria below:

  • ([AN count at baseline - AN count at current visit] / AN count at baseline) × 100% ≥ 90%
  • Abscess count at baseline ≥ abscess count at the current visit
  • Draining fistula count at baseline ≥ draining fistula count at the current visit.

HiSCR90 was evaluated using nonresponse imputation (NRI) and multiple imputation (MI) methods.
Week 12
Percentage of Participants Achieving HiSCR100 at Week 12
Time Frame: Week 12

The percentage of participants achieving HiSCR100 was defined as meeting all 3 criteria below:

  • ([AN count at baseline - AN count at current visit] / AN count at baseline) × 100% = 100%
  • Abscess count at baseline ≥ abscess count at the current visit
  • Draining fistula count at baseline ≥ draining fistula count at the current visit.

HiSCR100 was evaluated using nonresponse imputation (NRI) and multiple imputation (MI) methods.
Week 12
Percentage of Participants Achieving HiSCR50 at Week 12
Time Frame: Week 12

The percentage of participants achieving HiSCR50 was defined as meeting all 3 criteria below:

  • [(AN count at baseline - AN count at current visit) / AN count at baseline] × 100% ≥ 50%
  • Abscess count at baseline ≥ abscess count at the current visit
  • Draining fistula count at baseline ≥ draining fistula count at the current visit.

HiSCR50 was evaluated using nonresponse imputation (NRI) and multiple imputation (MI) methods.
Week 12
Percentage of Participants Who Experienced One or More (≥ 1) Disease Flare at Week 12
Time Frame: Up to Week 12

HS flares were defined as ≥ 25% increase in AN count with a minimum increase of 2 AN relative to baseline, i.e. participants must meet all the following criteria:

  • (AN count at current visit- AN count at baseline) / AN count at baseline ×100% ≥ 25%
  • AN count at current visit- AN count at baseline ≥ 2.

Participants who received antibiotic therapy that could affect HS were imputed as non-response (NRI). Other participants with missing data were imputed with multiple imputation.
Up to Week 12
Change From Baseline in Dermatology Life Quality Index (DLQI)
Time Frame: Baseline and Week 12
DLQI included 10 items arranged in 6 categories: symptoms and feelings, daily activity, leisure, work or study, interpersonal relationships, and treatment. The total score could range from 0 (no impact to life quality) to 30 (maximum impact).
Baseline and Week 12
Percentage of Participants With Baseline Hurley Stage II Who Achieved AN Count of 0, 1, or 2 at Week 12
Time Frame: Week 12

Calculated as observed values of 0, 1, or 2 for AN count (abscess count + inflammatory nodule count).

AN count of 0, 1, or 2 was evaluated using nonresponse imputation (NRI) and multiple imputation (MI) methods.
Week 12
Percentage of Participants With Baseline NRS ≥ 4 Achieving at Least 3-point Reduction at Week 12 in Numeric Rating Scale (NRS) Patient Global Assessment of Skin Pain at Its Worst
Time Frame: Week 12

NRS in Patient Global Assessment of Skin Pain ranged from 0 (no skin pain) to 10 (skin pain bad as you can imagine). The skin pain score at each visit was calculated using average of daily scores among the 7 days up to and including the day of visit, with a minimum of 4 days (consecutive or non-consecutive) with scores required.

Reduction in NRS was evaluated using nonresponse imputation (NRI) and multiple imputation (MI) methods.
Week 12
Number of Participants With Treatment-emergent Adverse Events (TEAEs), Serious AEs (SAEs) and Adverse Event of Special Interest (AESIs) in Period 1
Time Frame: Up to Week 16

An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study drug, whether or not considered related to the study drug.

An SAE is defined as any untoward medical occurrence that, at any dose, meets one or more of the criteria listed: results in death, is life threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, or is an important medical event.

The following events of special interest were monitored in this study: candida infection; inflammatory bowel disease (IBD); suicidal ideation; malignancies; major adverse cardiovascular and cerebrovascular events; tuberculosis; infections; cytopenias and systemic hypersensitivity reactions.

Clinically significant changes in vital signs and laboratory tests recorded after treatment administration were documented as TEAEs.
Up to Week 16
Number of Participants With TEAEs, SAEs and AESIs in Period 2
Time Frame: From Week 16 to follow-up, Week 59

An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study drug, whether or not considered related to the study drug.

An SAE is defined as any untoward medical occurrence that, at any dose, meets one or more of the criteria listed: results in death, is life threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, or is an important medical event.

The following events of special interest were monitored in this study: candida infection; IBD; suicidal ideation; malignancies; major adverse cardiovascular and cerebrovascular events; tuberculosis; infections; cytopenias and systemic hypersensitivity reactions.

Clinically significant changes in vital signs and laboratory tests recorded after treatment administration were documented as TEAEs.
From Week 16 to follow-up, Week 59

Collaborators and Investigators

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

Sponsor

ACELYRIN Inc.

Investigators

  • Study Director: Shephard Mpofu, ACELYRIN Inc.

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 (Actual)

June 22, 2023

Primary Completion (Actual)

July 24, 2024

Study Completion (Actual)

January 27, 2025

Study Registration Dates

First Submitted

June 7, 2023

First Submitted That Met QC Criteria

June 7, 2023

First Posted (Actual)

June 15, 2023

Study Record Updates

Last Update Posted (Estimated)

October 15, 2025

Last Update Submitted That Met QC Criteria

September 29, 2025

Last Verified

December 1, 2024

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 22107
  • 2022-503160-33-00 (Other Identifier: EU Clinical Trial Number)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

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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