Tag Archives: ustekinumab level

Therapeutic Drug Monitoring with Ustekinumab

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C McDonald et al. Inflammatory Bowel Diseases, Volume 30, March 2024, Pages 423–428. Open Access! Higher Ustekinumab Levels in Maintenance Therapy are Associated with Greater Mucosal Healing and Mucosal Response in Crohn’s Disease: An Experience of 2 IBD Centers

This retrospective study enrolled 47 patients receiving maintenance ustekinumab (UST) for Crohn’s disease. Over one-third of patients (n = 18, 38.3%) were on higher than standard dosing of 90 mg every 8 weeks. The study utilized drug-tolerant ELISA assay for UST trough levels and drug antibody titers.

Key findings:

  • In this observational cohort of patients with CD on maintenance UST, 63.8% of patients (n = 30 of 47) had achieved mucosal healing at time of level assay, and 85.1% (n = 40 of 47) had achieved at least mucosal response.
  • Patients with mucosal healing (n = 30) had significantly higher mean serum UST levels (5.7 µg/mL, SD 6.4) compared with those with no response (1.1 µg/mL, SD 0.52; n = 7, P < .0001).
  • Patients with mucosal healing (n = 30) had significantly higher mean serum UST levels (5.7 µg/mL, SD 6.4) compared with those with no response (1.1 µg/mL, SD 0.52; n = 7, P < .0001)
  • Similarly, for patients with mucosal response (n = 40), we observed a higher mean serum UST trough level (5.1 µg/mL, SD 6.1) compared with those with no response (1.1 µg/mL, SD 0.52; n = 7, P < .0001).
  • There were no antidrug antibodies detected in the cohort.

Discussion:

Unlike anti-TNF therapeutic drug monitoring, “there are few data supporting a correlation between serum ustekinumab levels and MH. The STARDUST randomized control trial34 is studying standard of care compared with treat-to-target ustekinumab therapy and has reported preliminary data at 1-year showing superiority of treat-to-target approaching achieving endoscopic response.”

My take: In this study, patients with UST levels above 2.3 μg/mL had a 10-fold level higher likelihood of mucosal healing and mucosal response. UST therapeutic drug monitoring can help “determine true nonresponse rather than insufficient dosing in patients who have not responded to UST.”

Other studies have suggested higher target levels. Mayo clinic lab site: “Concentrations > or =4.5 mcg/mL are associated with mucosal healing.” Ref: Papamichael K, Cheifetz AS, Melmed GY, et al. Appropriate therapeutic drug monitoring of biologic agents for patients with inflammatory bowel diseases. Clin Gastroenterol Hepatol. 2019;17(9):1655-1668.e3

 Mean through serum ustekinumab levels with standard deviation in patients who had achieved mucosal healing (n = 30), mucosal response (n = 40) or nonresponse (n = 7).

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How Much Ustekinumab (Stelara) Is Needed to Get a Good Response

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K Chen et al. Inflamm Bowel Dis 2023; 29: 1499-1503. Serum Ustekinumab Concentrations Are Associated With Improved Outcomes With the Magnetic Resonance Index of Activity for Crohn’s Disease

This retrospective trial included thirty three patients with Crohn’s disease (CD) receiving maintenance ustekinumab (UST). The simplified Magnetic Resonance Index of Activity (sMARIA) and biomarkers were correlated with UST levels. The authors utilized a homologous mobility shift assay (HMSA) (Prometheus) for their UST levels.

Key findings:

With UST level greater or equal to 8.4, radiologic remission was seen in 63% compared to 21% in those with levels <8.4. Similarly, the absence of severe inflammation was seen in 78.9% of those with higher levels compared with only 36.8% in those with levels below 8.4.
Both findings were clinically-significant P=.01
With UST levels greater or equal to 6.1, FCP less than 50 was seen in 72.2% compared to only 12.5% in those with a level less than 6.1. P<.01

My take: This study show the need for higher levels of UST to achieve optimal outcomes. Levels of at least 8.4 appear to be a good target.

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