Introduction A significant proportion of Crohn's disease (CD) patients have been treated with two biologic therapies. Follow-up from current published retrospective or prospective open-label studies on patients who have already received 2 biologics does not extend beyond 1 year (1-4).

Methods Our aim was to collect “real-life”, long-term data on the tolerability and efficacy of the second biologic agent in (re)-capturing response, and to assess whether the reason for stopping the first agent impacted on the successful use of the second agent. We carried out secure data collection from three teaching IBD centres on CD patients currently on, or already failed a second biologic. We collected data on disease duration, distribution and behaviour, and report on the aetiology in the failure of the first biologic and the subsequent outcome of the second biologic agent. Response to biologics was assessed by Harvey Bradshaw Index or Physicians Global Assessment.

Results We collected data on 66 patients (F 46%, mean age at diagnosis: 25). The disease distribution was characterised as L1: 11%, L2:32% L3:56% L4:1% and the behaviour as B1:41% B2:35% B3:24%. 17% had perianal involvement. 36 patients have had a total of 41 resectional operations.

First biologic: 64/66 patients had infliximab (IFX) first-line, followed by adalimumab (ADA), and 2/66 patients had ADA followed by IFX. Reasons for swapping were failure in 23%, secondary-loss of response in 38%, intolerance to the first agent in 29%, and fear of hypersensitivity reaction due to previous episodic exposure to IFX in 10% (irrespective of efficacy or tolerance).

Second biologic: 70% of patients remained on the second biologic after a median follow-up of 22 months. Reasons for discontinuing therapy were 1o failure in 35%, secondary loss of response in 25%, intolerance (or patient concerns regarding potential side-effects) in 25%, and achieving remission in 5%; no reason provided for the remainder 5%. Neither the demographics, disease characteristics nor the reason for failing the first biologic had a statistically significant bearing in predicting the initial response to and subsequent outcome of the second biologic.

Conclusions (1) We report an overall 70% retention on the second biologic at 22 months following all-cause failure of the first agent in CD patients from England and Ireland. (2) Patients responded equally well to the second biologic, irrespective of the reason for the failure of the first biologic.