THIOPURINE METABOLITES IN THE MANAGEMENT OF PATIENTS WITH INFLAMMATORY BOWEL DISEASE: A SINGLE CENTRE EXPERIENCE OF 100 SAMPLES

• Published in: Gut Vol. 62; no. Suppl 2; p. A4
• Main Authors: Hall, P S J, Ferguson, C B, Imrie, C, Lynch, M, Neely, A, Morrison, G
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Society of Gastroenterology 01.08.2013; BMJ Publishing Group LTD
• Subjects: 6-Mercaptopurine; Azathioprine; Drug dosages; Genetic variability; Inflammatory bowel disease; Inflammatory bowel diseases; Intestine; Laboratories; Management; Metabolites; Methyltransferase; Patients; Substance abuse treatment; Thioguanine; Thiopurine S-methyltransferase; Toxicity
• ISSN: 0017-5749; 1468-3288
• DOI: 10.1136/gutjnl-2013-305143.8

Introduction Thiopurine drugs are metabolised by a complex network of enzymes, each with individual genetic variability. Measurement of active metabolites, 6-thioguanine nucleotide (6-TGN) and 6-methylmercaptopurine nucleotide (6-MMPN), can have a role in optimising therapy for inflammatory bowel disease (IBD) patients.1 Aims/Background To evaluate how testing thiopurine metabolite(TPM) levels affects the management of patients with IBD receiving azathioprine or 6-mercaptopurine. Method A retrospective laboratory database search for TPM levels. The results were analysed in conjunction with outpatient letters and concurrent laboratory data. The primary outcome: how had measuring TPM levels affected patient management? Secondary objective: to combine demographic and test result data to provide information on the patterns of thiopurine drug use in this population. Results One hundred samples from 78 patients. 45% of samples led directly to changes in patient management. 15% led to dose escalation whilst 9% required dose reduction. The results of 8% led to the use of biological therapy. Treatment was stopped due to potential toxicity in 3%. In 8% of samples, patients were found to be poorly compliant with thiopurine treatment. 3 patients were completely non-compliant. In a sub-group of patients with low Thiopurine S-methyltransferase (TPMT), 78% had high levels of TGN despite the use of low drug doses. Figure 1 Metabolite Outcomes. Figure 2 Patient Management. Figure 3 Change to management. Conclusion Measuring TPMs is useful in the management of patients with IBD on thiopurines. They can reveal non-compliance and lead to dose alterations, treatment escalations and the prevention of drug toxicity. We would support the wider use of TPM testing in these patient groups.