Ustekinumab Concentrations Linked to Crohn Disease Radiologic, Biomarker Outcomes

Among patients with Crohn disease (CD), serum ustekinumab concentrations may be an indicator of radiologic and biomarker outcomes, according to study results presented at the American College of Gastroenterology (ACG) 2022 Annual Meeting, held from October 21 to 26, 2022, in Charlotte, North Carolina, and virtually.

Although ustekinumab is a common therapy used to treat CD, no serum concentrations that associate with outcomes have been established. To evaluate the relationship between ustekinumab concentrations and outcomes, investigators from Weill Cornell Medicine assessed serum concentrations among patients on over 16 weeks of ustekinumab maintenance therapy. Levels of ustekinumab were compared with radiologic remission, radiologic inflammation, and fecal calprotectin (FCP) outcomes. Radiologic remission was defined as simplified magnetic resonance enterography index (sMaRIA) less than 2, severe radiologic inflammation as sMaRIA less than 3, and FCP remission as less than 50 mg/g.

In 38 paired ustekinumab measurements and magnetic resonance imaging data, patients with radiologic remission were associated with higher ustekinumab concentrations (mean, 11.4 mg/mL) compared with patients not achieving radiologic remission (mean, 6.4 mg/mL; P =.005).

Ustekinumab concentrations had power as a diagnostic marker for radiologic remission (area under the receiver operating characteristic curve [AUROC], 0.76; 95% CI, 0.60-0.91) and for the absence of inflammation (AUROC, 0.71; 95% CI, 0.55-0.88). The optimal concentration of ustekinumab was 8.4 mg/mL, in which more patients with 8.4 mg/mL or above were in radiologic remission (63.2% vs 21.1%; P =.01) and did not have severe inflammation (78.9% vs 36.8%; P =.01) compared with patients who had levels below that threshold, respectively.

For FCP, ustekinumab also had diagnostic utility (AUROC, 0.73; 95% CI, 0.52-094). The optimal ustekinumab threshold for CRP remission was 6.1 mg/mL, in which more patients with a 6.1 mg/mL or greater ustekinumab were in CRP remission (72.2% vs 12.5%; P <.01) compared with patients with lower ustekinumab levels, respectively.

The major limitation of this study is the small sample size and the lack of an independent validation cohort.

“Ustekinumab concentrations are associated with radiologic and biomarker outcomes in CD,” the study authors wrote. “These data validate the need for higher ustekinumab concentrations.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.