A Study to Evaluate Efficacy and Safety of MK-8690 in Participants With Moderately to Severely Active Ulcerative Colitis (MK-8690-002)

A Phase 2a Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of MK-8690 in Adult Participants With Moderately to Severely Active Ulcerative Colitis

The purpose of this protocol is to evaluate the efficacy of MK-8690 in participants with moderately to severely active ulcerative colitis. The primary hypothesis is that MK-8690 is superior to placebo with respect to the proportion of participants achieving clinical remission per Modified Mayo Score at Week 12.

Study Overview

• Status: Recruiting
• Conditions: Ulcerative Colitis; Colitis Ulcerative
• Intervention / Treatment: Drug: MK-8690; Other: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Toll Free Number; Phone Number: 1-888-577-8839; Email: Trialsites@msd.com

Study Locations

• United States
  • California
    • Anaheim, California, United States, 92805
      • Recruiting
      • Clinnova Research ( Site 1042)
      • Contact: Study Coordinator; Phone Number: 949-889-0249
  • Colorado
    • Colorado Springs, Colorado, United States, 80907
      • Recruiting
      • Peak Gastroenterology Associates ( Site 1052)
      • Contact: Study Coordinator; Phone Number: 719-636-1201
    • Englewood, Colorado, United States, 80113
      • Recruiting
      • South Denver Gastroenterology, PC ( Site 1068)
      • Contact: Study Coordinator; Phone Number: 303-406-4288
  • Florida
    • Inverness, Florida, United States, 34452
      • Recruiting
      • Nature Coast Clinical Research ( Site 1045)
      • Contact: Study Coordinator; Phone Number: 352-341-2100
    • Miami, Florida, United States, 33134
      • Recruiting
      • Research Associates of South Florida - Miami - Southwest 8th Street ( Site 1072)
      • Contact: Study Coordinator; Phone Number: 786-476-8790
  • Georgia
    • Macon, Georgia, United States, 31201
      • Recruiting
      • Gastroenterology Associates of Central Georgia ( Site 1060)
      • Contact: Study Coordinator; Phone Number: 478-464-2600
  • Louisiana
    • New Orleans, Louisiana, United States, 70112
      • Recruiting
      • Tulane University School of Medicine ( Site 1073)
      • Contact: Study Coordinator; Phone Number: 504-988-5110
  • Missouri
    • Liberty, Missouri, United States, 64068
      • Recruiting
      • BVL Research - Kansas ( Site 1054)
      • Contact: Study Coordinator; Phone Number: 816-222-4241

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

The main inclusion criteria include but are not limited to the following:

• Has had ulcerative colitis (UC) (from onset of symptoms) for at least 3 months before Randomization
• Has moderately to severely active UC
• Has a weight ≥40 kg
• Satisfies at least 1 of the criteria: Has had an inadequate response or loss of response to 1 or more protocol-specified treatments; protocol specified corticosteroid dependence; has been intolerant to 1 or more protocol-specified UC treatments
• Is on treatment with any protocol-specified drugs during the study and meets drug stabilization requirements, as applicable

The main exclusion criteria include but are not limited to the following:

• Has a diagnosis of Crohn's Disease (CD) or indeterminate colitis (inflammatory bowel disease (IBD)-undefined) or other types of colitis or enteritis that may confound efficacy assessment
• Has a current diagnosis of fulminant colitis and/or toxic megacolon
• Has UC limited to the rectum
• Has a current or impending need for colostomy or ileostomy
• Has had a total proctocolectomy or partial colectomy
• Has UC exacerbation requiring hospitalization within 2 weeks before Screening
• Has any active infection as specified in the protocol
• Is known to be infected with hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV)
• Has evidence of active tuberculosis (TB) or meets TB exclusionary parameters
• Has a history of cancer (except fully treated nonmelanoma skin cell cancers or cervical carcinoma in situ after complete surgical removal) and is disease free for <5 years before Randomization or has a history of colorectal cancer at any time
• Has prior or current evidence of definite colonic dysplasia except for low-grade dysplasia that has been completely removed
• Has had major surgery within 3 months before Screening or has a major surgery (ie, surgical procedure requiring general anesthesia) planned during the study
• Has received protocol-specified prohibited medications

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Period 1: MK-8690; Participants will receive MK-8690 via subcutaneous injection for 12 weeks.	Drug: MK-8690; Solution for subcutaneous injection; Other Names: PRA052
Placebo Comparator: Period 1: Placebo; Participants will receive placebo via subcutaneous injection for 12 weeks.	Other: Placebo; Solution for subcutaneous injection
Experimental: Period 2: MK-8690; Participants who do not respond to treatment in Period 1 (regardless of treatment assignment in Period 1) will receive MK-8690 via subcutaneous injection for 12 weeks.	Drug: MK-8690; Solution for subcutaneous injection; Other Names: PRA052
Experimental: Period 3: MK-8690; Participants who respond to treatment in either Period 1 or Period 2 will receive additional MK-8690 via subcutaneous injection for up to approximately 42 weeks.	Drug: MK-8690; Solution for subcutaneous injection; Other Names: PRA052

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants Achieving Clinical Remission Per Modified Mayo Score (MMS) at Week 12	The MMS is a composite score of UC disease activity on a scale of increasing severity from 0-9, calculated by summing three subscores: Endoscopic subscore (ES), scored on a scale of increasing severity from 0 (normal or inactive disease) to 3 (severe disease, such as spontaneous bleeding or ulceration); Stool frequency subscore (SFS), scored on a scale of increasing frequency from 0 (normal number of stools) to 3 (≥5 stools more than normal per day for the participant); and rectal bleeding subscore (RBS), scored on a scale of increasing severity from 0 (no blood seen) to 3 (blood alone passed). Clinical Remission is defined as an ES of 0 or 1 with no friability, RBS of 0, and SFS of 0 or 1 and not greater than the baseline SFS.	Week 12

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants With One or More Adverse Events (AEs)	An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The percentage of participants who experience an AE will be reported.	Up to approximately 12 months
Percentage of Participants Who Discontinued Study Intervention Due to an AE	An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The percentage of participants who discontinue study treatment due to an AE will be reported.	Up to approximately 12 months
Percentage of Participants Achieving Clinical Response Per MMS at Week 12	The MMS is a composite score of UC disease activity on a scale of increasing severity from 0-9, calculated by summing three subscores: ES, scored on a scale of increasing severity from 0 (normal or inactive disease) to 3 (severe disease, such as spontaneous bleeding or ulceration); SFS, scored on a scale of increasing frequency from 0 (normal number of stools) to 3 (≥5 stools more than normal per day for the participant); and RBS, scored on a scale of increasing severity from 0 (no blood seen) to 3 (blood alone passed). Clinical response is defined as an MMS reduction of 2 or more points and 30% or more from baseline, plus a reduction of 1 or more points in RBS or an absolute RBS of 0 or 1.	Week 12
Percentage of Participants With Endoscopic Improvement at Week 12	Endoscopic improvement is defined as ES of 0 or 1 with no friability. The ES measures UC severity based on endoscopy on a 0-3 scale of increasing severity.	Week 12
Percentage of Participants Achieving Clinical Remission Per Partial Modified Mayo Score (pMMS) at Week 12	pMMS is a composite score of UC disease activity on a scale of increasing severity from 0-6, calculated by summing two subscores: SFS, scored from 0 (normal number of stools) to 3 (≥5 stools more than normal per day for the participant) and RBS, scored from 0 (no blood seen) to 3 (blood alone passed). Clinical remission per pMMS is defined as an RBS of 0 and SFS of less than or equal to 1.	Week 12
Percentage of Participants Achieving Histologic-Endoscopic Mucosal Improvement (HEMI) at Week 12	HEMI is defined as a Geboes score of 3.1 or less and ES of 0 or 1 with no friability. The Geboes score is a histologic grading system for inflammation in UC with scores ranging from 0 to 5.4, with higher scores indicating more severe inflammation. ES measures UC severity based on endoscopy, scored from 0 (normal or inactive disease) to 3 (severe disease, such as spontaneous bleeding or ulceration).	Week 12

Collaborators and Investigators

• Sponsor: Merck Sharp & Dohme LLC
• Investigators: Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

Helpful Links

• Merck Clinical Trials Information

Study record dates

Study Major Dates

• Study Start (Actual): March 24, 2026
• Primary Completion (Estimated): October 28, 2027
• Study Completion (Estimated): December 21, 2028

Study Registration Dates

• First Submitted: March 4, 2026
• First Submitted That Met QC Criteria: March 4, 2026
• First Posted (Actual): March 11, 2026

Study Record Updates

• Last Update Posted (Actual): May 26, 2026
• Last Update Submitted That Met QC Criteria: May 21, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Intestinal Diseases; Digestive System Diseases; Gastrointestinal Diseases; Colonic Diseases; Gastroenteritis; Inflammatory Bowel Diseases; Colitis; Colitis, Ulcerative
• Other Study ID Numbers: 8690-002; MK-8690-002 (Other Identifier: MSD); U1111-1326-7763 (Registry Identifier: UTN); 2025-523479-49-00 (Registry Identifier: EU CT)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No