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NCT Number: NCT07747467

A Study to Investigate the Safety and Tolerability of Multiple Study Interventions in Participants With Moderate to Severe Ulcerative Colitis

This study will look at how safe and tolerable different treatments are for adults who have moderate to severe ulcerative colitis (UC). The platform design uses one single master protocol that explains how the overall study is organized, whereas each treatment, as sub-study will be tested to see how well the study drug works and how it affects participants.

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Key information

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of UC for greater than or equal (>=) 3 months before screening. Appropriate documentation of endoscopy and biopsy results consistent with the diagnosis of UC, in the assessment of the investigator, must be available.
  • Active UC with a modified Mayo score (mMS) of 5 to 9 points and endoscopy sub score of 2 to 3 within 14 days before baseline biopsy collection.
  • Active disease beyond the rectum (greater than [>]15 centimeter [cm] of active disease from the anal verge at the screening colonoscopy).
  • Documentation of a surveillance colonoscopy (performed according to local standard) within 12 months before screening (may be performed during screening) for participants with pancolitis of >8 years duration or left-sided colitis of >12 years duration, or primary sclerosing cholangitis
  • Demonstrated an inadequate response to, loss of response to, or intolerance to conventional therapy (e.g., oral 5- aminosalicyclic acid [5-ASA] compounds, corticosteroids, thiopurines).
  • May have been receiving a conventional therapy if the prescribed dose has been stable for the required time period before the screening endoscopy

Exclusion criteria

  • Participants with current diagnosis of Crohn's disease (CD) or Inflammatory bowel disease-unclassified (IBD-U) or a history of radiation colitis, microscopic colitis or ischemic colitis.
  • Have currently known complications of UC such as fulminant colitis, or toxic megacolon, stoma, or stricture/stenosis within the small bowel or colon.
  • Have prior history of dysplasia of the gastrointestinal tract or found to have dysplasia, other than completely removed low-grade dysplastic lesions, in any biopsy performed during the screening endoscopy.
  • Have a history of malignant neoplasm within the last 5 years.
  • Have history of lymphoproliferative disorder, including lymphoma, or signs and symptoms suggestive of possible lymphoproliferative disease
  • Have any active, chronic, or recurrent infections based on the investigator's assessment.
  • Have history of opportunistic infections within 1 year of screening (
  • Have history or presence of significant medical illness including but not limited to cardiovascular, respiratory, gastrointestinal (excluding UC), hepatic, renal, endocrine, hematologic, neurological, and psychiatric disorders capable of significantly altering the absorption, metabolism, or elimination of drugs; constituting a risk when taking the study intervention or interfering with the interpretation of the data.
  • Have evidence of active or latent Tuberculosis (TB) as documented by medical history, examination, and TB testing at Screening.
  • Have significant allergies to humanized monoclonal antibodies.
  • Have clinically significant multiple or severe drug allergies, intolerance to topical corticosteroids, or severe post-treatment hypersensitivity reactions .
  • Have had previous colectomy (total or subtotal), or any other manifestation that might require surgery while enrolled in the trial.
  • Have ostomy or ileoanal pouch.
  • Have received any of the following for treatments of UC:
  • Immunomodulatory medications, including cyclosporine, tacrolimus, mycophenolate mofetil, thalidomide, within 4 weeks before screening endoscopy.
  • Topical (rectal) treatment of 5-ASA or corticosteroid enemas/suppositories within 2 weeks of screening endoscopy.
  • Have received approved or investigational advanced therapy (ATs) (i.e., biologics or small molecules including biosimilars).
  • Interferon therapy within 8 weeks before screening endoscopy.
  • Agents that deplete B- or T-cells (e.g., rituximab) within 12 months of baseline. Participants remain excluded if there is evidence of persistent targeted lymphocyte depletion at the time of screening endoscopy.
  • Had Clostridium difficile infection within 30 days of screening endoscopy or have a positive test result at screening, or other intestinal pathogen within 30 days before screening endoscopy.
  • Participant must not have signs of an ongoing infection related to an intestinal pathogen.
  • In the investigator's opinion, any clinically significant abnormalities of laboratory results from chemistry, hematology or urinalysis tests obtained at the screening visit that cannot be attributed to the underlying moderate-to-severe UC.
  • Pregnant or breastfeeding women, or women planning to become pregnant or breastfeed during the study.
  • History of a significant allergic reaction (anaphylaxis, urticaria) or significant sensitivity to study intervention or any constituents of the study interventions (including excipients).
  • Positive for hepatitis B or C, HIV (Human Immunodeficiency Virus), as assessed by method available at each site.

Treatment and study plan

Aletekitug (GSK1070806)

Biological

Aletekitug will be administered.

Other names: GSK1070806

Primary outcomes

  1. Number of Participants with Adverse Events (AEs)

    Time frame: Up to 34 weeks

    Adverse events will be collected.

  2. Number of Participants with Serious AEs (SAEs)

    Time frame: Up to 34 weeks

    Serious AEs will be collected.

  3. Number of Participants who Discontinue Study Intervention due to AEs

    Time frame: Up to 34 weeks

    Participants who discontinue study intervention due to AEs will be reported.

  4. Number of Participants with Clinically Significant Changes in Laboratory Readings

    Time frame: Up to 34 weeks

    Hematology, clinical chemistry, and urinalysis will be collected.

  5. Number of Participants with Clinically Significant Changes in Vital Signs

    Time frame: Up to 34 weeks

    Blood pressure, temperature and pulse rate readings will be collected.

  6. Number of Participants with Clinically Significant Changes in 12-lead Electrocardiogram (ECG) Readings

    Time frame: Up to 34 weeks

    ECG readings will be collected.

Study contacts

Contact information is provided by the study sponsor or research team.

EU GSK Clinical Trials Call Center

CONTACT

[email protected]

+44 (0) 20 89904466

US GSK Clinical Trials Call Center

CONTACT

[email protected]

877-379-3718

Sponsors and collaborators

Lead sponsor

GlaxoSmithKline

Industry

Registry information

Official study title

A Phase 1b, Non-Randomized, Open-Label, Repeat-Dose, Single Center Study Utilizing a Master Protocol to Investigate the Safety and Tolerability of Multiple Study Interventions in Advanced Therapy Naïve Participants With Moderate to Severe Ulcerative Colitis

Acronym: PEGASUS

Important dates

Study start
2026
Primary completion
2028
Study completion
2028
First posted
Aug 5, 2026
Registry last updated
Aug 5, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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