Predicting Adverse Events to Thiopurines in IBD: Are We a Step Closer?

Thiopurines remain an important option in the treatment of IBD. However, the unpredictable and sometimes serious side effects and intolerance remain a major challenge. Pretreatment of extended genetic panel analysis, identification of novel variants, and monitoring of intermediate metabolites will help improve the overall outcome and reduce the toxicity.

Ustekinumab or Vedolizumab after Failure of Anti-TNF Agents in Crohn's Disease: A Review of Comparative Effectiveness Studies.

Background: Anti-tumour necrosis factor (TNF) agents are effective in Crohn's disease (CD), but some patients lose responsiveness and require alternative biologic therapy. Until recently, ustekinumab and vedolizumab were the only other biological agents approved for use in CD. There are no randomised trials which compare the efficacy of these two agents in patients with anti-TNF refractory disease, but several retrospective cohort studies have compared their effectiveness in this setting. Aim: To review the effectiveness of ustekinumab and vedolizumab in anti-TNF refractory patients with CD. Methods: We included studies that compared the effectiveness of ustekinumab and vedolizumab in treating patients with anti-TNF refractory CD. We recorded the sample size, primary and secondary outcome measures and whether the studies employed adjustments for appropriate confounders. Results: Fourteen studies were included with a total sample size of 5651, of whom 2181 (38.6%) were treated with vedolizumab and the rest were treated with ustekinumab (61.4%). Of the fourteen studies included, eight found ustekinumab to be more effective in achieving clinical remission/steroid-free remission in the induction phase or during maintenance therapy (at least 1-year post-treatment) or that treatment persistence rates with ustekinumab were higher than with vedolizumab. Only one study reported vedolizumab to be superior during the maintenance phase in terms of clinical remission or treatment persistence rates. Biochemical outcomes were reported in five studies, two of which showed superiority for ustekinumab at 14 weeks and the other at 52 weeks. Only two studies reported endoscopic and/or radiologic outcomes; of these, one study showed ustekinumab to be significantly better at achieving endoscopic and radiologic responses. Adverse outcomes were broadly comparable, barring a single study which reported a lower hospitalisation rate for severe infection with ustekinumab. Conclusions: Most studies found ustekinumab to be more effective or non-inferior to vedolizumab in treating patients with anti-TNF refractory CD. Although many studies adjusted appropriately for confounders, the possibility of residual confounding remains and further data from prospective studies are warranted to confirm these findings. Further studies are required to compare these two therapies to other emerging therapies, such as Janus-kinase inhibitors.