Icotrokinra in ulcerative colitis: what 76 week remission results mean

More than half of the icotrokinra recipients who entered the ANTHEM-UC extension were in clinical remission at week 76. The followup adds evidence about continued treatment in ulcerative colitis, but entry depended on an earlier response and there was no continuing randomized placebo comparison.[1]

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An oral peptide reaches a longer test

Icotrokinra blocks the receptor for interleukin 23, or IL-23, a signal involved in inflammation. Its appeal in ulcerative colitis is the prospect of targeting that pathway with an oral peptide. The Johnson & Johnson funded Phase 2b ANTHEM-UC study enrolled adults with moderately to severely active disease who had an inadequate response or intolerance to conventional or advanced treatment.[2][3][4]

The sponsor reported extension results at the American College of Gastroenterology meeting held October 9 to 14. They address a practical question: can early benefit persist? The initial trial randomized 252 participants. Eligibility for the longer followup depended on how participants were doing after that first treatment period.[1][2]

This is a different clinical question from the drug’s established psoriasis indication. The FDA’s March approval of Icotyde covered plaque psoriasis. Our earlier coverage of icotrokinra’s psoriasis results concerns skin disease, not these bowel inflammation endpoints.[5]

What the randomized trial established

At week 12, clinical response occurred in 40 of 63 participants assigned to 400 mg, 36 of 62 assigned to 200 mg and 35 of 64 assigned to 100 mg, compared with 17 of 63 assigned to placebo. These were the trial’s treatment groups, not comparisons between different studies. Each active group met the primary endpoint against placebo.[2][4]

Response meant a specified improvement in the modified Mayo score, which combines stool frequency, rectal bleeding and an endoscopic assessment of the bowel. Remission required a more demanding combination: no rectal bleeding, a low stool frequency score without worsening from baseline, and little or no visible inflammation under the trial’s endoscopic definition.[3]

At week 12, remission occurred in 30% of the 400 mg group (63 participants) versus 11% of the placebo group (63 participants). The 200 mg remission comparison (62 participants) reached P=0.054, so the prespecified sequence of secondary statistical tests stopped there. Positive primary response results therefore do not make every secondary result statistically confirmed.[2]

The extension changed who was being counted

Participants responding at week 28 could enter the extension. Earlier, at week 16, placebo recipients with inadequate response could switch to icotrokinra; after unblinding, remaining placebo treatment was discontinued. Other ulcerative colitis medicines could also be adjusted during the extension.[1][3]

The week 76 analysis included 136 icotrokinra recipients. Clinical remission occurred in 25 of 44 in the 400 mg group, 26 of 44 in the 200 mg group and 27 of 48 in the 100 mg group. Missing outcomes counted as nonresponses, and local endoscopists supplied the bowel inflammation readings used in the remission assessment.[1]

The endpoint is remission at a particular visit among people selected for earlier response. It leaves two different questions open: how often any newly treated patient would reach that visit in remission, and whether each participant had remained in remission throughout the intervening months.

Safety has its own observation window

The original publication’s adverse event comparison covers the first 28 weeks. The extension’s final safety assessment was at week 78, two weeks after its main efficacy assessment. By that later stage, placebo had been discontinued and participants were being followed through continued treatment.[1][2]

Johnson & Johnson reported no new safety signal through week 78. Its summary also records ductal carcinoma in situ, a noninvasive breast cancer, during the extension. Reporting an event during treatment does not establish that treatment caused it. The small followup population leaves uncertainty about uncommon harms.[1]

What the later remission measurement adds

The controlled phase and extension fit together as evidence about starting treatment and continuing it. The initial placebo comparison supports a treatment effect on early clinical response. The later remission results show that meaningful disease control remained possible well beyond those first months.[1][2]

For someone following the prospect of an oral IL-23 treatment, the distinction is practical: the 76 week result describes a later checkpoint for selected responders. It is not a forecast of 76 uninterrupted weeks of remission for everyone who starts.