Effects of Concomitant Immunomodulator Therapy on Efficacy and Safety of Anti-Tumor Necrosis Factor Therapy for Crohn's Disease: A Meta-analysis of Placebo-controlled Trials

Background & Aims: There is debate over whether patients with Crohn's disease who start anti-tumor necrosis factor (TNF) therapy after failed immunomodulator therapy should continue to receive concomitant immunomodulators. We conducted a meta-analysis of subgroups from randomized controlled trials (RCTs) of anti-TNF agents to compare the efficacy and safety of concomitant immunomodulator therapy vs anti-TNF monotherapy. Methods: We performed a systematic review of literature published from 1980 through 2008 and identified 11 RCTs of anti-TNF agents in patients with luminal or fistulizing Crohn's disease. We excluded RCTs of patients who were naive to anti-TNF and immunomodulator therapy. The primary end points were clinical response at weeks 4-14 and 24-30 and remission at weeks 24-30. Secondary end points included infusion site or injection site reactions and selected adverse events. A priori subgroup analyses were performed to evaluate fistula closure and the efficacy and safety of combination therapy with different anti-TNF agents. Results: Overall, combination therapy was no more effective than monotherapy in inducing 6-month remission (odds ratio [OR], 1.02; 95% confidence interval [CI], 0.80-1.31), inducing a response (OR, 1.08; 95% CI, 0.79-1.48), maintaining a response (OR, 1.53; 95% CI, 0.67-3.49), or inducing partial (OR, 1.25; 95% CI, 0.84-1.88) or complete fistula closure (OR, 1.10; 95% CI, 0.68-1.78). In subgroup analyses of individual anti-TNF agents, combination therapy was not more effective than monotherapy in inducing 6-month remission in those treated with infliximab (OR, 1.73; 95% CI, 0.97-3.07), adalimumab (OR, 0.88; 95% CI, 0.58-1.35), or certolizumab (OR, 0.93; 95% CI, 0.65-1.34). Overall, combination therapy was not associated with an increase in adverse events, but inclusion of infliximab was associated with fewer injection site reactions (OR, 0.46; 95% CI, 0.26-0.79.). Conclusions: On the basis of a meta-analysis, continued use of immunomodulator therapy after starting anti-TNF therapy is no more effective than anti-TNF monotherapy in inducing or maintaining response or remission. RCTs are needed to adequately assess the efficacy of continued immunomodulator therapy after anti-TNF therapy is initiated.