Thiopurine Monotherapy Effective in Ulcerative Colitis, But Less So in Crohn’s Disease

Sarfaroj Khan 


October 19, 2020


  • Thiopurine monotherapy is an effective long-term treatment for ulcerative colitis (UC), but significantly less effective in Crohn’s disease (CD), particularly where there is perianal involvement.

Why this matters

  • Given recent substantial reductions in the cost of biosimilars and the evidence presented regarding the relative lack of durable effectiveness of thiopurine monotherapy in CD, there is perhaps a need to re-evaluate treatment strategy of using thiopurines as maintenance for patients with CD.

Study design

  • A retrospective analysis of long-term outcomes of thiopurine monotherapy for 11,928 patients with inflammatory bowel disease (IBD) (UC, n=4968; CD, n=6960) in the UK IBD BioResource (68,132 patient-years of exposure).

  • Funding: None disclosed.

Key results

  • Thiopurine monotherapy was effective for the duration of treatment in 2617/4968 (52.7%) patients with UC vs 2378/6960 (34.2%) patients with CD (P<.0001).

  • Multivariable logistic regression analysis demonstrated that thiopurine monotherapy was less effective in CD than UC (OR, 0.47; 95% CI, 0.43-0.51; P<.0001) after adjusting for variables including treatment era.

  • For CD, treatment initiation ≤1 year after IBD diagnosis (OR, 0.69; 95% CI, 0.60-0.78; P<.0001) and perianal disease (OR, 0.70; 95% CI, 0.61-0.80; P<.0001) correlated with lower thiopurine effectiveness.

  • For UC, proctitis was associated with higher effectiveness (OR,1.56 vs extensive disease; 95% CI, 1.23-1.98; P=.0002).

  • On Kaplan-Meier analysis, median duration on thiopurines in those in whom they were effective was 16 years for CD and 17 years for UC.

  • Inability to tolerate thiopurines was associated with an increased risk of surgery in UC (HR, 2.44; 95% CI, 1.71-3.50; P<.0001), with a more modest effect in CD (HR, 1.23; 95% CI, 1.08-1.40; P=.0015).


  • Retrospective design.


Stournaras E, Qian W, Pappas A, Hong YY, Shawky R, Raine T, Parkes M. Thiopurine monotherapy is effective in ulcerative colitis but significantly less so in Crohn's disease: long-term outcomes for 11 928 patients in the UK inflammatory bowel disease bioresource. Gut. 2020 Oct 1 [Epub ahead of print]. doi: 10.1136/gutjnl-2019-320185. PMID: 33004550 View full text

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.


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