Therapeutic Drug Monitoring of Golimumab for the Prediction of Long-Term Clinical Remission in Patients with Ulcerative Colitis

BACKGROUND AND AIMS: A considerable number of patients with ulcerative colitis (UC) who initially respond to golimumab (GLM), an anti-TNF-α antibody, gradually lose clinical response. Therapeutic drug monitoring has been proposed to optimize serum anti-TNF-α antibody concentrations before the loss of response; however, little is known about ideal serum GLM concentrations. We aimed to evaluate whether the serum GLM trough levels (TLs) early after the initiation of induction therapy affect the long-term outcomes in UC and to identify the early GLM TLs that should be targeted for better long-term outcomes. METHODS: Thirty-one patients were prospectively evaluated. The primary outcome was clinical remission at 54 weeks, and we measured the serum GLM TLs at weeks 6, 10, and 14. Receiver operating characteristic (ROC) curves were constructed to identify optimal GLM TL thresholds early after induction therapy that were associated with clinical remission at week 54. RESULTS: The GLM TL at week 14, but not at weeks 6 or 10, was significantly associated with clinical remission at week 54 (median [IQR] 1.6 [1.3–1.6] μg/mL vs. 0.9 [0.6–1.3] μg/mL; p = 0.04). The area under the ROC curve for GLM TLs at week 14 was 0.78. We identified a week-14 GLM TL of 1.1 μg/mL as the target threshold for achieving clinical remission at week 54. CONCLUSION: Our results demonstrate the value of early serum GLM TLs in predicting the long-term outcomes of GLM for patients with UC.