Table 1.

Characteristics of patients who discontinued subcutaneous vedolizumab due to injection site reactions and switched back to intravenous treatment.

IBD type	Montreal classification	Previous treatments	Duration of IV VDZ treatment (months)	Duration of SC VDZ treatment (months)	Type of reaction to SC injection	Type of reaction to IV injection after switch back	S-VDZ at first infusion with reactions(mg/L)	VDZ discontinuation
CD	L2B1	Azathioprine Infliximab	25	2	Erythema, swelling and pruritus at injection site	Erythema, swelling and pruritus at former injection site the first 2 infusions	30.2	No
CD	L3B3	Azathioprine Methotrexate Adalimumab Infliximab	49	4	Pruritus at injection site	None	30.9	No
UC	E3	5-ASA Golimumab Infliximab	53	3	Erythema, swelling and pruritus at injection site	Erythema, swelling and pruritus at former injection site first 2 infusions Rhinorrhoea, pruritus in the throat and red eyes shortly after third and fourth infusion, and during the fifth infusion. pretreatment IV hydrocortisone without effect	41.6	Yes
UC	E3	5-ASA Azathioprine Infliximab	32	6	Erythema, swelling and pruritus at injection site	Erythema, swelling and pruritus at former injection site at all infusions after switch, decreasing severity but ongoing 18 months after switch	26.9	No

Abbreviations: IBD, inflammatory bowel disease; CD, Crohn’s disease; UC, ulcerative colitis; Montreal classification (CD): L1 ileum, L2 colon, L3 ileocolon, B1 non-structuring non-penetrating, B3 penetrating, (UC): E3 involvement proximal to the splenic flexure; IV, intravenous; VDZ, vedolizumab; SC, subcutaneous; S-VDZ, serum-vedolizumab.