Introduction Conventional thiopurines (Azathioprine/6 Mercaptopurine) remain the cornerstone of maintaining remission in steroid-dependent inflammatory bowel disease (IBD). Despite the well-documented efficacy of these drugs, more than 50% of patients discontinue treatment due to adverse events or therapy resistance. Over the past decade, there has been renewed interest in the use of 6 thioguanine (TG), an agent historically used in haematological malignancy. With a shorter metabolic pathway, TG possesses a favourable side effect profile and it’s use as an alternative thiopurine in IBD is growing. We report our experience in tolerability, safety and efficacy of TG use in a London District General Hospital.
Methods A retrospective review of electronic patient records including clinic letters, blood tests and endoscopic findings were carried out on patients commenced on TG between 2012 and 2015. Data was collected on patient demographics, indication and duration of therapy, response rates and reasons for treatment failure.
Results A total of 28 patients received TG 20 mg once daily and median treatment duration was 14 months (range 1–40). Therapy was equally distributed amongst males and females (14:14), and mean age was 44 years (range 19–67). 14 (50%) patients had Ulcerative colitis (UC), 13 (46%) Crohn’s disease (CD) and 1 (4%) Indeterminate colitis. 24 patients (86%) received TG due to adverse reactions to conventional thiopurines vs. 3 patients (11%) who were non-responders. Treatment with TG resulted in clinical remission in 86% (19/22) patients at 6 months and 75% (12/16) at 12 months. In total, 6 patients (21%) discontinued TG – 4 failed treatment (2 continued alternative medical therapy and 2 had surgery) and 2 suffered adverse events (headaches and confusion). Tolerability and efficacy rates were similar in both UC and CD groups. All patients underwent blood monitoring and no abnormalities in liver function tests were detected. Of those who underwent MRI liver there was no evidence of nodular regenerative hyperplasia.
Conclusion TG was well tolerated with comparable remission rates to conventional thiopurine therapy. We advocate the use of TG therapy in selected cases where conventional thiopurine therapy has failed or resulted in adverse reactions. Larger prospective trials are required to further evaluate the efficacy and safety of TG, with a view to potentially incorporate it’s use into clinical guidelines.
Disclosure of Interest None Declared