“…Plans for a trial directly comparing two TNFi therapies (certolizumab and adalimumab), the first of its kind, have recently been announced [102]. Comparison across randomized controlled trials has been undertaken using the number needed to treat (NNT) to achieve response, as this should not be affected by clinical differences between the study populations, without revealing any remarkable differences; amongst new biologic therapies (including CZP), the NNT to achieve one ACR50 response at 1 year was between 4 and 6 [38], and amongst all five available TNFi therapies, the NNT for ACR50 response at 6 months fell between 3 and 5 [39]. Use of a loading regimen with CZP may improve its speed of onset; a pharmacokinetic study demonstrated that 80% of ultimate ACR20 responders achieved this response at week 8, compared with week 12 when loading was not undertaken [40], and in the RAPID Phase III trials (in which a loading regimen was employed) continued improvements in ACR20 response were seen up to week 12, after which they plateaued [8,9].…”