Eleven RCTs were included in the review. There were concerns about the quality of the trials, in particular those that assessed maintenance therapy. These centred on division of patients into responders and non-responders at different time points, high rates of scheduled cross-overs between treatment groups and unclear handling of data (including missing data). The use of responder only data in maintenance trials was a particular issue.
Adult patients with non-fistulising disease
In two induction trials between 6% and 24% more patients treated with adalimumab achieved remission compared with placebo; in one infliximab trial between 21% and 44% more patients achieved remission. In maintenance trials benefits of between 24% and 29% more patients achieved remission for adalimumab (two trials) and between 14% and 24% for infliximab (two trials). These results were based on changes in the Crohn's Disease Activity Index and reflected results across a range of doses.
Adult patients with fistulising disease
One induction trial showed that between 29% and 42% more patients achieved a 50% reduction in fistulas compared with placebo; 23% more patients in a maintenance trial achieved this reduction compared with placebo. Subgroup results from two additional RCTs provided contradictory indications as to whether adalimumab conferred any benefit.
It appeared likely that infliximab therapy for children offered a benefit of increased remission but the lack of a placebo group in either the induction or the maintenance trial made this difficult to determine.
There were few differences in selected adverse events between groups.
Other outcomes were also reported as were some results for patients who did not respond to treatment.