Proof of Concept Study Evaluating the Efficacy and Safety of ATH-063 Treatment in Patients With Relapsed/Refractory Moderately to Severely Active Ulcerative Colitis (UC)

NCT07513181 | Not Yet Recruiting Phase 2 DMC FDA Drug

• 2 other identifiers: ATH-002-0002024-520183-33-00
• Study Type: interventional
• Target: 120
• Locations: 1 country
• Sites: 2

Brief Summary

The primary objective of this trial is to evaluate the clinical efficacy of ATH-063 in participants with biologic/advanced therapy relapsed/refractory moderately to severely active UC.

Conditions

Autoimmune Diseases; Ulcerative Colitis; Inflammatory Bowel Diseases

Keywords

Colitis; Ulcerative; IBD; Biologic refractory

Outcome Measures

Primary Outcomes (1)

• Clinical Remission at Week 12

  Clinical remission is defined as a ulcerative colitis disease severity score (UCDSS) of 0 to 2, including the following components: a stool frequency subscore (SFS) of 0 (on a scale from 0 to 3, with higher scores indicating higher frequency) or an SFS of 1 with a decrease of at least 1 point from baseline; a rectal bleeding subscore (RBS) of 0; and a centrally read endoscopic mucosal appearance (EMA) subscore of 0 or 1. The UCDSS (0 to 9 points) is the sum of the following 3 components: RBS (0 to 3), SFS (0 to 3), and EMA subscore (0 to 3), with higher scores indicating more severe disease.

  At Week 12

Secondary Outcomes (5)

• Number of Participants With Treatment-emergent Adverse Events (TEAEs), Serious TEAEs, and TEAEs Leading to Trial Discontinuation

  Up to Week 36

• Clinical Response at Week 12

  At Week 12

• Change From Baseline in UCDSS at Week 12

  At Week 12

• Proportion of Participants Who Achieve FDA-defined Clinical remission at Week 12

  At Week 12

• Clinical Response at Week 24 Among Participants Who Received Placebo During the First 12 Weeks and ATH-063 in a 12-week Follow-up

  From Week 12 to Week 24

Study Arms (2)

ATH-063 150 mg

EXPERIMENTAL

Participants will be randomized to receive ATH-063 150 mg orally QD for 12 weeks, with posttreatment follow-up at Weeks 16 and 24.

Drug: ATH-063

Placebo

PLACEBO COMPARATOR

Participants will be randomized to receive matching placebo orally QD for 12 weeks, with posttreatment follow-up at Weeks 16 and 24.

Other: Placebo

Interventions

ATH-063 DRUG

Three 50 mg capsules, total dose 150 mg.

ATH-063 150 mg

Placebo OTHER

Identical capsule to the drug without the active ingredient.

Placebo

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Able to understand and willing to provide informed consent and able to comply with the trial procedures and restrictions.
• Male or female (assigned at birth, inclusive of all gender identities) participants 18 to 75 years of age, inclusive, at the time of informed consent.
• Male or female participants must be postmenopausal/surgically sterile, sexually abstinent, or using 2 forms of protocol-specified contraception, including 1 physical barrier method (condom or diaphragm) plus 1 highly effective method (ie, hormonal contraception., intrauterine device, intrauterine hormone-releasing system, bilateral occlusion, vasectomy, or complete sexual abstinence). Women of childbearing potential (WOCBP) must also be nonpregnant and not breastfeeding.
• Has a diagnosis of UC confirmed by endoscopic and histologic evidence at least 4 months before screening. If confirmation is not available in source documentation, the screening endoscopy and histology reports for this trial may serve as evidence.
• Has moderately to severely active UC, defined as a UCDSS of 5 to 9, with an EMA subscore of 2 to 3 (obtained during the central review of the screening video endoscopy).
• Has active UC that extends \>15 cm beyond the anal verge, as identified at the screening colonoscopy.
• Has documentation of moderately to severely active UC that is refractory (inadequate response - signs and symptoms of persistently active disease despite induction treatment at the approved induction dosing indicated in the product label; or loss of response - recurrence of signs and symptoms of active disease during maintenance dosing following prior clinical benefit \[discontinuation despite clinical benefit does not qualify as having failed biologic therapy\]) to 1 to 2 prior approved biologic/advanced UC therapies (ie, biologic therapies, such as antitumor necrosis factor \[TNF\], anti-integrin, and anti-interleukin \[IL\]-12/23 therapies; or advanced therapies, such as sphingosine 1-phosphate \[S1P\] receptor modulators and Janus kinase \[JAK\] inhibitors \[eg, tofacitinib\]; one of which must have been an anti-TNF therapy; the other, if applicable, may have had the same or a different mechanism of action) when given at doses approved for the treatment of UC.
• Has documentation of an inadequate response, loss of response, or intolerance to conventional standard-of-care therapy with corticosteroids (ie, prednisone and budesonide), 5-ASAs (ie, mesalamine, sulfasalazine), or other immunomodulators (ie, thiopurines, methotrexate, cyclosporine, and tacrolimus).
• Any prior therapy, including any investigational drug, not permitted as concomitant standard-of-care therapy must have been discontinued for at least 4 weeks or 5 half-lives prior to screening, whichever is longer, or the participant must have no active drug detected at the start of screening, as determined by therapeutic drug monitoring.
• Has screening laboratory test results within the following parameters:
• Hemoglobin ≥8 g/dL
• White blood cell (WBC) ≥3×103/μL
• Neutrophil count ≥1.5×103/μL
• Platelet count ≥100,000/μL
• Serum creatinine ≤1.5 mg/dL and/or creatinine clearance \>80 mL/min

You may not qualify if:

• Clinically significant abnormal medical history, or abnormal findings on physical examination, vital signs, ECG, or laboratory tests at screening, that the investigator judges as likely to interfere with the objectives of the trial or the safety of the participant.
• Surgery (eg, stomach bypass) or medical condition that might significantly affect absorption of oral medicines (as judged by the investigator).
• Hospitalization for exacerbation of UC requiring intravenous (IV) corticosteroids (ie, UC flare) within 12 weeks prior to screening.
• Current evidence of fulminant colitis, toxic megacolon, or recent history (within 6 months prior to screening) of toxic megacolon, or bowel perforation.
• Investigator judgment that the participant is likely to require a colectomy within 12 weeks of the start of trial medication administration.
• Has UC that is limited to the rectum or right colon.
• Presence or history of an enteric fistula consistent with Crohn's disease (CD).
• History of ischemic colitis.
• History of indeterminate colitis or microscopic colitis.
• History of radiation colitis.
• History of CD.
• History of colonic stricture.
• History or evidence of any extensive colonic resection or subtotal or total colectomy (with or without presence of a stoma or ileoanal pouch) that would prevent adequate evaluation of trial intervention on clinical disease activity, as per the investigator's judgment.
• Current colonic adenomas, dysplasia, or past confirmed colonic dysplasia that has not been eradicated (participants who have had UC \>8 years should have had a colonoscopy to screen for dysplasia within 1 year prior to the screening visit, or this can be performed as part of the screening colonoscopy). A participant with prior history of adenomatous polyps will be eligible if the polyps have been completely removed (documented), and the participant is free of polyps and does not have evidence of dysplasia on histologic evaluation at screening.
• Any current malignancy judged by the investigator not to be in full remission (except for basal cell and in situ squamous cell carcinomas of the skin that have been fully excised and resolved). Prior malignancy must have been in remission for \>2 years prior to screening.

Sponsors & Collaborators

• Athos Therapeutics Inc: lead

Study Sites (2)

Miami Clinical Research

Miami, Florida, 33155, United States

Location

Gastroenterology Consultants, P.C.

Roswell, Georgia, 30076, United States

Location

MeSH Terms

Conditions

Colitis, Ulcerative; Inflammatory Bowel Diseases; Autoimmune Diseases; Colitis; Ulcer

Condition Hierarchy (Ancestors)

Gastroenteritis; Gastrointestinal Diseases; Digestive System Diseases; Colonic Diseases; Intestinal Diseases; Immune System Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• David T. Rubin, MD

  University of Chicago Biological Sciences Division

  STUDY DIRECTOR

Central Study Contacts

Allan Pantuck, MD

CONTACT

contact via email; apantuck@athostx.com

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: Following completion of the 12-week double-blind period, participants who wish to continue into the open-label extension will be unblinded.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 1, 2026
• First Posted: April 6, 2026
• Study Start: June 1, 2026
• Primary Completion (Estimated): December 14, 2028
• Study Completion (Estimated): December 14, 2028
• Last Updated: June 8, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

US (2)