“…88 There are isolated case reports of development of de novo IBD or flaring of IBD linked to administration of IL-1 antagonists, including anakinra and canakinumab, 70,89 anti-IL-6R antibody tocilizumab, 71,86 CTLA-4-Fc fusion protein abatacept, 90,91 and the anti-vascular endothelial growth factor monoclonal antibody bevacizumab. 92 Case reports and observational studies describe IBD-like histological changes, including FAC and chronic colitis, in a range of other medications, including tyrosine kinase inhibitors such as dasatinib, 93,94 sunitinib and sorafenib, 95,96 proteasome inhibitor bortezomib, 97 immune modulators such as tacrolimus, 68 azathioprine, 98 leflunomide, 69 hydroxycarbamide 53 treatments for hepatitis C including interferon and/or ribavirin, [99][100][101][102] sofosbuvir, simeprevir, 103,104 and gold. 105 Isotretinoin is a synthetic analogue of vitamin A, approved for treatment of severe recalcitrant nodular acne.…”