Hidradenitis SuppurativaPhase 2NCT05216224
ATI-450 vs Placebo in Participants With Moderate to Severe Hidradenitis Suppurativa (HS)
A Phase 2 study testing ATI-450 in people with Hidradenitis Suppurativa, run by Aclaris Therapeutics, Inc. at 20 sites in United States.
Trial summary
This is a Phase 2a study to investigate the efficacy, safety, tolerability, pharmacokinetics, and pharmacodynamics of ATI-450 vs placebo in patients with moderate to severe Hidradenitis Suppurativa (HS). Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Hidradenitis Suppurativa
- What is being tested?
- ATI-450
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 95 participants
- Where
- 20 sitesUnited States
- Study dates
- 29 Dec 2021to 24 Jan 2023
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Able to comprehend and be willing to sign the Institutional Review Board (IRB)-approved participant informed consent form prior to administration of any study-related procedures.
- Participant must have stable HS.
- Total abscesses and/or nodule (AN) count of ≥5 at Baseline visit.
- HS lesions present in at least 2 distinct anatomical areas at Screening and Baseline.
Who cannot join
- Participant has a history of active skin disease other than HS that could interfere with the assessment of HS.
- Participant has an uncontrolled non-immunoinflammatory disease that may place the participant at increased risk during the study or impact the interpretation of results, e.g., previous malignancy, previous venous thromboembolism.
- Participant has experience with >2 biologics, >1 Janus kinase (JAK) inhibitor, or a combination of 1 biologic experience and 1 JAK inhibitor.
- Are currently receiving corticosteroids at doses greater than 10 mg per day of prednisone (or equivalent) or have been receiving an unstable dosing regimen of corticosteroids within 2 weeks of the Screening visit.
Trial locations and contacts
20 sites in 1 country.
20 sites in 1 country
United States20 sites
Aclaris Investigational Site
Anderson, South Carolina, 29621
Aclaris Investigational Site
Athens, Ohio, 45701
Aclaris Investigational Site
Birmingham, Alabama, 35244
Aclaris Investigational Site
Boca Raton, Florida, 33486
Aclaris Investigational Site
Charlotte, North Carolina, 28277
Aclaris Investigational Site
Encino, California, 91436
Aclaris Investigational Site
Fort Gratiot, Michigan, 48059
Aclaris Investigational Site
Fort Smith, Arkansas, 72916
Aclaris Investigational Site
Hershey, Pennsylvania, 17033
Aclaris Investigational Site
Hollywood, Florida, 33021
Aclaris Investigational Site
Houston, Texas, 77054
Aclaris Investigational Site
Marietta, Georgia, 30060
Aclaris Investigational Site
Mason, Ohio, 45040
Aclaris Investigational Site
Metairie, Louisiana, 70006
Aclaris Investigational Site
Nashville, Tennessee, 37215
Aclaris Investigational Site
San Francisco, California, 94115
Aclaris Investigational Site
Sandy Springs, Georgia, 30328
Aclaris Investigational Site
Sugar Land, Texas, 77478
Aclaris Investigational Site
Tampa, Florida, 33613
Aclaris Investigational Site
Thousand Oaks, California, 91436
About this study
Official title: A Phase 2a, Randomized, Double-blind, Placebo-controlled Study to Investigate the Efficacy, Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of ATI-450 vs Placebo in Patients With Moderate to Severe Hidradenitis Suppurativa (HS)
This is a Phase 2a study to investigate the efficacy, safety, tolerability, pharmacokinetics, and pharmacodynamics of ATI-450 vs placebo in patients with moderate to severe Hidradenitis Suppurativa (HS).
- Conditions
- Hidradenitis Suppurativa
- Being tested
- ATI-450, Placebo oral tablet
- Keywords
- Hidradenitis, Suppurativa, HS, Acne inversa
- Medical subject headings
- Hidradenitis Suppurativa, Hidradenitis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ATI-450Drug
Also called Zunsemetinib
Oral, small molecule MK2 inhibitor
Placebo oral tabletDrug
Also called Placebo
Placebo tablet manufactured to match ATI-450 in appearance
| Study group | Role | What they receive |
|---|---|---|
| ATI-450 | Experimental | ATI-450 50 milligrams (mg) oral tablet twice daily (BID) Receives: Drug: ATI-450 |
| Placebo | Experimental | Placebo oral tablet BID Receives: Drug: Placebo oral tablet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change From Baseline in Abscess and Inflammatory Nodule (AN) Count at Week 12
AN count was the sum of number of abscess and inflammatory nodules across anatomical regions.
The least square (LS) mean change from baseline in the count at Week 12 was estimated from the Mixed Model Repeated Measures (MMRM) model.
Measured: Baseline, Week 12
Secondary outcomes (7)
Percentage of Participants Achieving Hidradenitis Suppurativa Clinical Response (HiSCR50) at Week 12
HiSCR50 Achiever was defined as a participant having a ≥50% reduction from baseline in the total abscess and inflammatory nodule count, with no increase in the number of abscesses, and no increase in the number of draining fistula counts from baseline. A participant was considered an achiever only if all 3 criteria mentioned above were fulfilled.
Model-based estimates and 90% confidence intervals (CIs) were produced. Firth's penalized likelihood logistic regression model with fixed effects for treatment and baseline count of inflammatory abscesses and nodules was used.
Measured: Week 12
Change From Baseline in International Hidradenitis Suppurativa Severity Score System (IHS-4) at Week 12
The IHS-4 is a validated tool used to access the HS severity and is calculated based on the clinical signs of HS: inflammatory nodules, abscesses and draining tunnels (fistulas and sinuses). The IHS-4 score = (number of nodules multiplied by 1) + (number of abscesses multiplied by 2) + (number of draining tunnels [fistulas/sinuses] multiplied by 4).
Mild HS is a score of 3 or less, moderate HS is a score of 4-10, and severe HS is a score of 11 or higher. A decrease in score means less severity.
Measured: Baseline, Week 12
Percentage of Participants Achieving NRS30
NRS30 Achiever was defined as participants achieving at least a 30% reduction from baseline in Patient's Global Assessment of Skin Pain (PGA-SP) and at least 1 unit reduction from baseline in PGA-SP at Week 12 among participants with baseline PGA-SP ≥3.
Model-based estimates and 90% CIs were produced. Firth's penalized likelihood logistic regression model with fixed effects for treatment and baseline PGA-SP was used.
Measured: Week 12
Change From Baseline in Hidradenitis Suppurativa-Physician Global Assessment (HSPGA) at Week 12
In the HS-PGA scale, the Investigators rated the counts of nodules (inflammatory and non-inflammatory) abscesses and fistulas (both draining and nondraining) and assigned a participant to 1 of 6 categories ranging from clear (0) to very severe (5). A decrease in score means a better outcome.
Measured: Baseline, Week 12
Change From Baseline in Dermatology Life Quality Index (DLQI) at Week 12
The DLQI is a 10-item validated questionnaire used to assess the impact of HS disease symptoms and treatment on quality of life (QoL). It consists of questions including a single "yes/no" question and questions with possible responses of "not at all," "a little," "a lot," or "very much." These questions evaluate the impact of skin diseases on different aspects of a participant's QoL over the prior week, including symptoms and feelings, daily activities, leisure, work or school, personal relationships, and the side effects of treatment. Each question was scored using a 4-point scale ranging from 0 to 3 based on a participant's response: not at all/not relevant (0), a little (1), a lot (2) and very much (3). The total score of the DLQI ranged from 0 to 30 and was calculated by adding up the scores from each question. The higher the score, the greater the impact on a participant's QoL.
Measured: Baseline, Week 12
Number of Participants With Treatment-emergent Adverse Events (TEAEs)
TEAEs are defined as AEs with an onset date on or after the date of first administration of study drug and before the date of last administration of study drug + 30 days. A summary of non-serious AEs and serious AEs, regardless of causality is located in Reported AEs section.
Measured: Baseline through Day 115
ATI-450 and Metabolite (CDD-2164) Concentrations
Measured: 2 hours postdose on Days 1, 8, and 85
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Jan 2022
- Study start29 Dec 2021
- Primary completion23 Dec 2022
- Study completion24 Jan 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Hidradenitis SuppurativaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Randomized, double-blind, placebo-controlled study
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 95 participants (actual)
Sponsor and investigators
- Lead sponsor
- Aclaris Therapeutics, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Ajay Aggarwal, Study director, Aclaris Therapeutics, Inc.
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05216224
- Sponsor's protocol ID
- ATI-450-HS-201
- Status last verified
- Dec 2025
- First submitted
- 19 Jan 2022
- Last updated
- 7 Jan 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 7 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2a, Randomized, Double-blind, Placebo-controlled Study to Investigate the Efficacy, Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of ATI-450 vs Placebo in Patients With Moderate to Severe Hidradenitis Suppurativa (HS)
- ClinicalTrials.gov ID
- NCT05216224
- Acronym / sponsor ID
- ATI-450-HS-201
- Conditions
- Hidradenitis Suppurativa
- Keywords
- Hidradenitis, Suppurativa, HS, Acne inversa
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 95 participants (actual)
- Lead sponsor
- Aclaris Therapeutics, Inc.Industry (pharma, biotech, devices)
- Study start
- 29 Dec 2021 (actual)
- Primary completion
- 23 Dec 2022 (actual)
- Study completion
- 24 Jan 2023 (actual)
- First posted
- 31 Jan 2022 (actual)
- Results
- Posted 7 Jan 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a Phase 2a study to investigate the efficacy, safety, tolerability, pharmacokinetics, and pharmacodynamics of ATI-450 vs placebo in patients with moderate to severe Hidradenitis Suppurativa (HS).
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Randomized, double-blind, placebo-controlled study
| Arm | Type | Receives |
|---|---|---|
| ATI-450 | Experimental | Drug: ATI-450ATI-450 50 milligrams (mg) oral tablet twice daily (BID) |
| Placebo | Experimental | Drug: Placebo oral tabletPlacebo oral tablet BID |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Able to comprehend and be willing to sign the Institutional Review Board (IRB)-approved participant informed consent form prior to administration of any study-related procedures.
- Participant must have stable HS.
- Total abscesses and/or nodule (AN) count of ≥5 at Baseline visit.
- HS lesions present in at least 2 distinct anatomical areas at Screening and Baseline.
Key exclusion criteria (4 listed)
- Participant has a history of active skin disease other than HS that could interfere with the assessment of HS.
- Participant has an uncontrolled non-immunoinflammatory disease that may place the participant at increased risk during the study or impact the interpretation of results, e.g., previous malignancy, previous venous thromboembolism.
- Participant has experience with >2 biologics, >1 Janus kinase (JAK) inhibitor, or a combination of 1 biologic experience and 1 JAK inhibitor.
- Are currently receiving corticosteroids at doses greater than 10 mg per day of prednisone (or equivalent) or have been receiving an unstable dosing regimen of corticosteroids within 2 weeks of the Screening visit.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ATI-450Also: ZunsemetinibOral, small molecule MK2 inhibitor | Drug | ATI-450 |
| Placebo oral tabletAlso: PlaceboPlacebo tablet manufactured to match ATI-450 in appearance | Drug | Placebo |
Primary outcome
Change From Baseline in Abscess and Inflammatory Nodule (AN) Count at Week 12
Time frame: Baseline, Week 12
AN count was the sum of number of abscess and inflammatory nodules across anatomical regions. The least square (LS) mean change from baseline in the count at Week 12 was estimated from the Mixed Model Repeated Measures (MMRM) model.
7 secondary outcomes
Percentage of Participants Achieving Hidradenitis Suppurativa Clinical Response (HiSCR50) at Week 12
Time frame: Week 12
Change From Baseline in International Hidradenitis Suppurativa Severity Score System (IHS-4) at Week 12
Time frame: Baseline, Week 12
Percentage of Participants Achieving NRS30
Time frame: Week 12
Change From Baseline in Hidradenitis Suppurativa-Physician Global Assessment (HSPGA) at Week 12
Time frame: Baseline, Week 12
Change From Baseline in Dermatology Life Quality Index (DLQI) at Week 12
Time frame: Baseline, Week 12
Number of Participants With Treatment-emergent Adverse Events (TEAEs)
Time frame: Baseline through Day 115
ATI-450 and Metabolite (CDD-2164) Concentrations
Time frame: 2 hours postdose on Days 1, 8, and 85
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Jan 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Related trials for Hidradenitis Suppurativa
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Early Pathophysiology of Hidradenitis Suppurativa and Prediction of the Risk of Progression: a Prospective Cohort
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A Study of Zasocitinib in Adults With Hidradenitis Suppurativa
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Acceptability of MBSR for People With HS
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Rollover Study for Participants Previously Enrolled in Clinical Trials of Povorcitinib
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Ajay Aggarwal study director
Aclaris Therapeutics, Inc.
20 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing ATI-450 in people with Hidradenitis Suppurativa, run by Aclaris Therapeutics, Inc. at 20 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 20 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 7 Jan 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change From Baseline in Abscess and Inflammatory Nodule (AN) Count at Week 12 (time frame: Baseline, Week 12). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Jan 2026.