As the Global Medical Aff airs Gastroenterology Lead for tofacitinib at Pfi zer, I read with great interest the review by Dr Ungar and Dr Kopylov entitled “Advances in the development of new biologics in infl ammatory bowel disease (IBD)” [1]. In reading the article, I identifi ed a number of inaccuracies concerning tofacitinib, which I thought should be brought to the attention of the authors and your readers. Th roughout the article tofacitinib is described as being a “biologic”. Although it may be appropriate to compare the effi cacy and safety of tofacitinib to the existing biologic therapies used in IBD, tofacitinib is a synthetic small molecule JAK inhibitor and not a biologic agent. Tofacitinib was introduced along with descriptions of the biologics, including anti-integrins and ustekinumab. It would be more accurate if tofacitinib was split from these biologic agents and instead described in a separate sentence, since antiintegrins and ustekinumab are biologics and tofacitinib is not. In relation to safety events, in place of the current “Th e adverse eff ect profi le for tofacitinib appears to be similar to other biologics...”, it would be more accurate to state that “Th e adverse eff ect profi le for tofacitinib appears to be similar to that of biologics...”, thus separating tofacitinib from the biologic drug class. With respect to the discussion around immunogenicity and tofacitinib, because tofacitinib is a synthetic small molecule JAK inhibitor and not a biologic agent we would not expect there to be any immunogenicity. Hence, no specifi c studies of the immunogenicity of tofacitinib have been performed or are planned at present. Finally, we are nearing completion of a phase 3 development program of tofacitinib in ulcerative colitis [2,3] and we look forward to sharing the results of these studies with the gastroenterological community in the future.