Janssen posts Phase 3 ustekinumab results in pediatric ulcerative colitis

Janssen Research & Development, LLC posted results of its Phase 3 study of ustekinumab in pediatric participants with moderately to severely active ulcerative colitis in the trial registry on October 20, 2026. The study, known as UNIFI Jr, enrolled 112 participants. According to the record, 25 percent of them were in clinical remission at induction Week 8, one of nine primary outcomes the record lists.

Induction Week 8 results

All 112 participants received a single intravenous dose of ustekinumab at induction Week 0, with the dose set by body weight. The record gives 250 milligrams per square meter for participants under 40 kilograms, 260 mg for 40 to 55 kilograms, 390 mg for more than 55 to 85 kilograms and 520 mg above 85 kilograms.

The record defines clinical remission through Mayo subscores: a stool frequency subscore of 0 or 1, a rectal bleeding subscore of 0, and an endoscopy subscore of 0 or 1 with no friability present on the endoscopy, where the stool frequency subscore has not increased from induction baseline. The record reports 25 percent in clinical remission at induction Week 8, with a 95% confidence interval of 17.9 to 33.8.

The record lists four related measures as secondary outcomes at induction Week 8, each as a percentage of the 112 participants:

clinical response: 67.0 (95% confidence interval 57.8 to 75.0)
symptomatic remission: 48.2 (39.2 to 57.4)
endoscopic improvement: 30.4 (22.6 to 39.4)
histologic-endoscopic mucosal improvement: 19.6 (13.3 to 28.0)

Maintenance period

According to the record, 109 of the 112 participants completed the induction period. The record lists three who did not: one for an adverse event, one for lack of efficacy and one for starting a prohibited medication.

The 109 were randomized into the maintenance period: 55 to subcutaneous ustekinumab every 12 weeks and 54 to every 8 weeks. Maintenance was double-blind, with matching placebo given at other visits to hide the schedule. The record lists 46 participants completing maintenance in the every 12 weeks arm and 49 in the every 8 weeks arm.

The maintenance measures cover participants who were in clinical response at induction Week 8 and received at least one maintenance dose: 40 in the every 12 weeks arm and 39 in the every 8 weeks arm. The record lists these as secondary outcomes at Maintenance Week 44:

clinical remission: 32.5 percent in the every 12 weeks arm (95% confidence interval 20.1 to 48.0) and 48.7 percent in the every 8 weeks arm (33.9 to 63.8)
symptomatic remission: 57.5 percent (42.2 to 71.5) and 74.4 percent (58.9 to 85.4)
endoscopic improvement: 32.5 percent (20.1 to 48.0) and 48.7 percent (33.9 to 63.8)
histologic-endoscopic mucosal improvement: 27.5 percent (16.1 to 42.8) and 46.2 percent (31.6 to 61.4)

The posted results show each arm separately and list no statistical comparison between the two arms.

Safety measures

The record lists the safety measures among its nine primary outcomes. The counts below are participants, as posted, for the induction period and the two maintenance arms in that order:

treatment-emergent adverse events: 59 of 112, 52 of 55 and 48 of 54
treatment emergent serious adverse events: 6, 2 and 5
adverse events leading to discontinuation of study intervention: 2, 3 and 2
adverse events of special interest: 0, 1 and 0
reactions temporally associated with intravenous infusion, or subcutaneous injection-site reactions: 3, 0 and 1

The record also posts counts of participants with abnormal hematology and chemistry results by grade.

Participants

The record describes a randomized, parallel, double-masked Phase 3 study. Its official title calls for open-label intravenous induction treatment followed by randomized double-blind subcutaneous maintenance. The study started in 2021, and the record lists primary completion and completion in 2025.

Participants were 2 to 17 years old. Of the 112, 30 were 2 to under 12 years and 82 were 12 to under 18 years, with a mean age of 13.2 years. The record lists 61 female and 51 male participants. By region, 59 enrolled in Poland, 13 in Belgium, 11 in Hungary, 10 in Japan, 8 in Germany, 4 in the United Kingdom, 4 in the United States and 3 in Israel.

Participants needed a diagnosis of ulcerative colitis before screening and a baseline Mayo score of 6 through 12, with a screening Mayo endoscopy subscore of 2 or higher.

The record also reports serum ustekinumab concentrations, a primary outcome. The mean was 115.269 micrograms per milliliter 1 hour after the infusion at Week I-0 (105 participants, standard deviation 30.4642) and 5.018 at Week I-8 (84 participants, standard deviation 3.6498).

The record answers yes on sharing individual participant data. Requests for access to the study data can be submitted through the Yale Open Data Access (YODA) Project, according to the record.