Variability in Golimumab Exposure: A 'Real-Life' Observational Study in Active Ulcerative Colitis

Abstract

Background and aims: Golimumab has been approved recently to treat refractory moderate-to-severe ulcerative colitis [UC]. To date it is not clear why a considerable fraction of patients do not respond, or lose initial response, to golimumab therapy. Our aim was to investigate whether a low golimumab serum concentration and/or a positive anti-golimumab antibody status reduces the efficacy of this drug in patients with UC.

Methods: Serum samples of 21 patients with moderate-to-severe UC were collected during the first 14 weeks of golimumab therapy. For measurement of golimumab serum concentrations, both a tumour necrosis factor [TNF]-coated enzyme-linked immunosorbent assay [ELISA] and a sandwich-type ELISA were developed. Anti-golimumab antibodies were measured using a bridging ELISA and a newly-developed drug-tolerant immunoassay. Clinical response and mucosal healing were assessed 14 weeks after start of treatment.

Results: Out of 21 patients, 10 [48%] reached partial clinical response at Week 14. Median [interquartile range] serum golimumab concentration was significantly higher in partial clinical responders than in non-responders: 10.0 [7.8-10.5] µg/ml versus 7.4 [4.8-8.3] µg/ml at Week 2 [p = 0.035] and 5.1 [4.0-7.9] µg/ml versus 2.1 [1.8-4.2] µg/ml at week 6 [p = 0.037]. Four out of 21 UC patients developed anti-golimumab antibodies, detectable only using a drug-tolerant immunoassay, and three had a partial clinical response at that time. Clinical non-responders had a significantly more severe colitis, indicated by a higher endoscopic Mayo score at baseline compared with partial clinical responders [p = 0.048].

Conclusion: Adequate exposure to golimumab drives clinical response. A worse disease at baseline influences clinical response rate negatively.

Keywords: Therapeutic drug monitoring; golimumab; ulcerative colitis.

Copyright © 2016 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Figures

Figure 1.

Drug exposure as defined by area under the curve (AUC [Weeks 0–6]) of golimumab for partial clinical responders [solid black line] and non-responders [dashed black line].

Figure 2.

Detection of anti-golimumab antibody in the presence of various concentrations of golimumab using the drug-tolerant immunoassay. Determination of 500ng/ml MA-GOM159B8, spiked with golimumab concentrations between 0 and 10 µg/ml [molar excess up to 20-fold].

Figure 3.

The course of golimumab concentrations [solid line, left y-axis] and anti-golimumab antibody concentrations as measured using drug-tolerant immunoassay [dashed line, right y-axis] in four individual patients. The dotted line represents the cut-off [25ng/ml MA-GOM159B8 equivalents] of the drug-tolerant immunoassay. [A] Non-responder. [B, C, and D] Partial clinical responders.