Phase 2a Randomized, Double‑Blind, Placebo‑Controlled Study of Subcutaneous MK‑8690 in Adults with Moderately to Severely Active Ulcerative Colitis

The primary objective is to determine the efficacy of MK-8690 compared with placebo, measured by the proportion of participants achieving clinical remission according to the Modified Mayo Score at Week 12, a clinically meaningful endpoint reflecting disease control in ulcerative colitis. Secondary objectives include:

• assessment of the safety and tolerability of MK-8690;
• evaluation of the proportion of participants attaining a clinical response per Modified Mayo Score at Week 12;
• evaluation of endoscopic improvement at Week 12;
• assessment of clinical remission using the partial Modified Mayo Score at Week 12;
• evaluation of histologic‑endoscopic mucosal improvement at Week 12.

A total of 62 participants with a confirmed diagnosis of ulcerative colitis were enrolled. Both male and female subjects were included; the specific age range was not detailed in the available data. All participants had disease duration of at least three months, exhibited moderately to severely active disease, and weighed at least 40 kg. Enrollment required an inadequate or lost response to at least one protocol‑specified therapy, corticosteroid dependence, or intolerance to a protocol‑specified treatment, and participants were required to be on a stable regimen of any protocol‑specified medication during the study. The primary efficacy assessment was based on the proportion of subjects achieving clinical remission according to the Modified Mayo Score at Week 12.

The study is a Phase 2a randomized, double-blind, placebo-controlled trial evaluating the efficacy and safety of subcutaneous MK‑8690 versus matching placebo in adult participants with moderately to severely active ulcerative colitis; the primary endpoint is the proportion achieving clinical remission at Week 12 as defined by the Modified Mayo Score. After an initial screening visit to confirm eligibility (ulcerative colitis duration ≥3 months, weight ≥40 kg, and inadequate response or corticosteroid dependence on standard therapies), eligible individuals are randomized and receive study medication for a 12‑week treatment period with follow‑up visits at Weeks 4, 8, and 12 to assess clinical response, endoscopic findings, histology, and adverse events. An end‑of‑study visit at Week 12 completes the intervention phase, after which participants may enter a safety follow‑up. Total participant involvement spans approximately 14 weeks, including screening and a final safety check. Early termination may occur if a participant experiences a serious adverse event, withdraws consent, or fails to meet protocol‑defined safety or efficacy criteria.

The investigational product, MK-8690, is supplied as a concentrate for solution for injection intended for subcutaneous administration. Each dose is prepared at a concentration of 00 % (V/V) and is administered via subcutaneous injection according to the study‑specified dosing schedule.

The control arm receives a placebo matching MK‑8690 in appearance. The placebo contains no active substance, has no defined pharmaceutical form, and is administered by the same route and schedule as the active investigational product to maintain blinding.

All administrations are performed under study protocol conditions, with dosing times recorded in the trial database. Participant compliance is monitored through scheduled site visits and documentation of each injection, ensuring adherence to the prescribed regimen.

Efficacy will be evaluated by determining the proportion of participants who achieve clinical remission according to the Modified Mayo Score at Week 12. Participants will be assessed at baseline and at the Week 12 visit using the validated scoring system, and the percentage meeting remission criteria will be calculated for the MK‑8690 and placebo groups.

Secondary efficacy assessments include the proportion of participants achieving clinical response per the Modified Mayo Score, the proportion with endoscopic improvement, the proportion achieving remission based on the Partial Modified Mayo Score, and the proportion demonstrating Histologic‑Endoscopic Mucosal Improvement, all evaluated at Week 12. Endoscopic and histologic evaluations will be performed using standard colonoscopic techniques and biopsy analysis. All efficacy parameters will be analyzed using appropriate statistical methods to compare the MK‑8690 and placebo arms.