Optimized thiopurine therapy before withdrawal of anti-tumour necrosis factor- in patients with Crohn's disease

ObjectiveTwo meta-analyses have found that the risk of relapse in Crohn's disease (CD) was 40 and 50% 1 and 2 years, respectively, after withdrawal of anti-tumour necrosis factor- (anti-TNF). The aim of this study was to evaluate relapse rates in CD when thiopurine therapy was optimized before anti-TNF withdrawal.Patients and methodsAn observational study was conducted including patients with CD in remission with optimized thiopurine therapy before anti-TNF withdrawal. We defined optimized thiopurine therapy as 6-thioguanine levels of at least 150nmol/mmol haemoglobin (approximate to 300pmolx10(8) red blood cells) and clinical/biochemical remission as Harvey-Bradshaw Index of 5 or less and faecal calprotectin of 200 mu g/g or less.ResultsWe included 33 patients (median age: 31 years, 55% males, and median disease duration: 7 years) followed for a median of 36 months. A total of three (9%) patients relapsed during the first year and six patients (in total 27%) relapsed after 2 years. After 2 years, none of the additional patients relapsed. The disease duration and duration of anti-TNF treatment and faecal calprotectin levels before inclusion did not predict relapse. Calprotectin levels of at least 180 after 1 year predicted relapse at year 2.ConclusionThis study found that 73% of patients with CD maintained remission (>2 years) when thiopurine therapy was optimized before withdrawal of anti-TNF. Additional prospective evidence is needed to confirm the findings.