A Study to Evaluate the Efficacy, Safety, Tolerability and Pharmacokinetics of PTT-621 in Patients With Moderately to Severely Active Ulcerative Colitis

August 4, 2026 updated by: Pyrotech Therapeutics, Inc.

A Phase IIa, Multicenter, Single-Arm Study to Evaluate the Efficacy, Safety, Tolerability and Pharmacokinetic Characteristics of PTT-621 in Patients With Moderately to Severely Active Ulcerative

This Phase IIa, multicenter, single-arm trial evaluates the efficacy, safety, tolerability, and pharmacokinetics of PTT-621 tablets in adults (18-70 years) with moderate-to-severe active ulcerative colitis (UC) who have inadequate response/intolerance to standard therapies. Participants receive PTT-621 for 12 weeks. The primary endpoint is the proportion of participants achieving endoscopic improvement at Week 12. Secondary endpoints include safety, clinical remission, clinical response, symptom response, pharmacokinetics, and inflammatory biomarkers. The study is sponsored by Pyrotech Therapeutics, with ethical approval from Renji Hospital's IRB.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Phase 2

Contacts and Locations

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

Study Contact

Study Locations

  • China
    • Shanghai Municipality
      • Shanghai, Shanghai Municipality, China, 200127
        • Renji Hospital-Shanghai Jiao Tong University School of Medicine
        • Contact:

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:

  • 1. Male or female participants aged 18-70 years inclusive at screening. 2. Diagnosed with ulcerative colitis (UC) at least 60 days prior to the first dose of IP.

    3. Participants have active UC at screening, defined as a modified Mayo score of 5-9.

    4. Endoscopic evidence of UC extending ≥15 cm from the anal verge during the screening period.

    5. Participants have had inadequate/loss of response or intolerance to at least one of the following: 5-aminosalicylic acid, glucocorticoids, immunosuppressants, biologics, and/or small-molecule targeted therapies.

    6. Participants currently receiving the following UC therapies are eligible if they meet stability requirements: Oral glucocorticoids: with stable dosing for ≥2 weeks prior to screening endoscopy；Oral 5-ASA: Stable dose for at least 2 weeks prior to the endoscopic assessment during the screening period.

    7. Female participants of childbearing potential must have a negative serum/urine pregnancy test at screening.

    8. Willing to use at least one highly effective contraceptive method during sexual intercourse throughout the study and until 1 month after the last dose of IP.

    9. Willing to refrain from sperm/ova donation throughout the study and until 1 month after the last dose of IP.

    10. Able and willing to provide written informed consent and comply with all protocol-specified procedures and visit schedules.

Exclusion Criteria:

  • 1. A current diagnosis of Crohn's disease (CD), indeterminate colitis, infectious colitis, or any other colitis/enteritis that could interfere with efficacy evaluation； 2. Has UC complications (e.g., fulminant colitis, toxic megacolon, prior total or partial colectomy, or other conditions requiring surgery)； 3. Prior or current gastrointestinal dysplasia； 4. History of gastrointestinal malignancy, or any current evidence of gastrointestinal cancer.

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: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Participants receiving PTT-621 Dose A
Drug: PTT-621 Tablets
PTT-621 will be administered orally

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Percentage of participants achieving endoscopic improvement at Week 12
Time Frame: Week 12
Week 12

Secondary Outcome Measures

Outcome Measure
Time Frame
Percentage of participants with adverse events (AEs)
Time Frame: Baseline, Week 2, 4, 8, 12
Baseline, Week 2, 4, 8, 12
Percentage of participants achieving clinical remission、clinical response
Time Frame: Week 12
Week 12
Percentage of participants achieving symptom remission, symptom response
Time Frame: Weeks 2, 4, 8, 12
Weeks 2, 4, 8, 12
Pharmacokinetic (PK) characteristics: Plasma concentrations of PTT-621
Time Frame: Baseline, Weeks 2, 4, 8, 12
Baseline, Weeks 2, 4, 8, 12
Changes in fecal calprotectin from baseline
Time Frame: Weeks 2, 4, 8, 12
Weeks 2, 4, 8, 12
Changes in high-sensitivity C-reactive protein (hsCRP) from baseline
Time Frame: Week 2, 4, 8, 12
Week 2, 4, 8, 12

Collaborators and Investigators

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

Sponsor

Pyrotech Therapeutics, 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 (Estimated)

August 1, 2026

Primary Completion (Estimated)

December 1, 2027

Study Completion (Estimated)

June 1, 2028

Study Registration Dates

First Submitted

July 27, 2026

First Submitted That Met QC Criteria

July 30, 2026

First Posted (Actual)

August 5, 2026

Study Record Updates

Last Update Posted (Actual)

August 7, 2026

Last Update Submitted That Met QC Criteria

August 4, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PTT-621-201

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

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.

Subscribe