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ATI-450

Phase 2

Hidradenitis Suppurativa | Small molecule | Dermatology |Aclaris Therapeutics, Inc.|Last Updated: Jan 7, 2026

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindCONTROLLEDDMC
Total Trials1
Total Enrollment95

FDA Designations

No designations recorded

Clinical trial landscape

ATI-450 · 3 trials · 2 indications

Phase 2 3
NCT05279417ATI-450 Plus Methotrexate (MTX) Versus Placebo Plus MTX in Participants With Moderate to Severe Active Rheumatoid Arthritis (RA)Rheumatoid Arthritis
COMPLETED251 Analytics
NCT05216224ATI-450 vs Placebo in Participants With Moderate to Severe Hidradenitis Suppurativa (HS)Hidradenitis Suppurativa
COMPLETED95 Analytics
NCT04247815Study of ATI-450 Plus Methotrexate (MTX) vs MTX Alone in Patients With Moderate to Severe RARheumatoid Arthritis
COMPLETED25 Analytics
PHASE2COMPLETED
ATI-450 Plus Methotrexate (MTX) Versus Placebo Plus MTX in Participants With Moderate to Severe Active Rheumatoid Arthritis (RA)
Rheumatoid ArthritisUnlock trial analytics
PHASE2COMPLETED
ATI-450 vs Placebo in Participants With Moderate to Severe Hidradenitis Suppurativa (HS)
Hidradenitis SuppurativaUnlock trial analytics
PHASE2COMPLETED
Study of ATI-450 Plus Methotrexate (MTX) vs MTX Alone in Patients With Moderate to Severe RA
Rheumatoid ArthritisUnlock trial analytics

Study Endpoints

Primary Endpoints

Proportion of patients achieving ACR20 at Week 12
Baseline to Week 12
Change From Baseline in Abscess and Inflammatory Nodule (AN) Count at Week 12
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.

The Primary Outcome Measure is the Determination of the Safety and Tolerability of ATI-450 Plus Methotrexate in Patients With Moderate to Severe Rheumatoid Arthritis: Adverse Events (AEs)
Baseline through Day 114

Safety and tolerability reported as Adverse Events (AEs). AEs will be coded with the Medical Dictionary for Regulatory Activities (MedDRA) version 23.0. AEs will be presented by system organ class and preferred term in frequency tables.

Secondary Endpoints

Proportion of patients achieving ACR50/70 at Week 12
Baseline to Week 12
Proportion of patients achieving ACR20/50/70 over time
Up to 12 Weeks
Mean change from baseline in DAS28-CRP over time
Up to 12 Weeks
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
ATI-450 20 mg BID plus MethotrexateEXPERIMENTALATI-450 20 mg oral tablet twice daily (BID) with a stable weekly dose of methotrexate for 12 weeks
ATI-450 50 mg BID plus MethotrexateEXPERIMENTALATI-450 50 mg oral tablet BID with a stable weekly dose of methotrexate for 12 weeks
Placebo plus MethotrexatePLACEBO_COMPARATORPlacebo oral tablet BID with a stable weekly dose of methotrexate for 12 weeks
ATI-450EXPERIMENTALATI-450 50 milligrams (mg) oral tablet twice daily (BID)
PlaceboEXPERIMENTALPlacebo oral tablet BID
ATI-450 plus MethotrexateEXPERIMENTALATI-450 50mg oral tablet BID with a stable weekly dose of Methotrexate

Interventions

NameTypeDescription
ATI-450 50 mg oral tablet BIDDRUGOral, small molecule MK2 inhibitor
Placebo oral tabletDRUGPlacebo tablet manufactured to match ATI-450 in appearance
MethotrexateDRUG15 mg to 25 mg weekly
ATI-450 20 mg oral tablet BIDDRUGOral, small molecule MK2 inhibitor
ATI-450DRUGOral, small molecule MK2 inhibitor
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Eligibility Criteria

Age Range18 Years to 75 Years
SexALL
Healthy VolunteersNo
Study Sites50

Inclusion Criteria: * Able to comprehend and be willing to sign the Institutional Review Board (IRB)/Independent Ethics Committee (IEC) approved participant ICF prior to administration of any study-related procedures. * Diagnosis of adult-onset RA as defined by the 2010 American College of Rheumato...

Countries:United StatesBulgariaCzechiaPoland
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Frequently asked questions about ATI-450

What is ATI-450 used for?

ATI-450 is an investigational small molecule being studied for the treatment of hidradenitis suppurativa and rheumatoid arthritis. It is currently in Phase 2 clinical development and has not been approved by the FDA.

Who makes ATI-450?

ATI-450 is being developed by Aclaris Therapeutics, Inc., a biopharmaceutical company traded on the NASDAQ under the ticker symbol ACRS.

What phase is ATI-450 in?

ATI-450 is in Phase 2 clinical development. It is an investigational drug and has not been approved by the FDA. Clinical trials have been completed for both hidradenitis suppurativa and rheumatoid arthritis.

What clinical trials is ATI-450 in?

ATI-450 has been studied in three completed Phase 2 trials: NCT04247815 and NCT05279417 for rheumatoid arthritis, and NCT05216224 for hidradenitis suppurativa. These trials were randomized, double-blind, and controlled, with a total enrollment of 276 participants.

Is ATI-450 the same as any other drug?

No alternative names for ATI-450 have been reported. It is referred to solely as ATI-450 in clinical trial records and by its developer, Aclaris Therapeutics.