Anti-IL-12/23p40 antibodies for induction of remission in Crohn's disease.

BACKGROUND: Ustekinumab (CNTO 1275) and briakinumab (ABT-874) are monoclonal antibodies that target the standard p40 subunit of the cytokines interleukin-12 and interleukin-23 (IL-12/23p40), which are involved in the pathogenesis of Crohn's disease.

OBJECTIVES: The objectives of this review were to assess the efficacy and safety of anti-IL-12/23p40 antibodies for induction of remission in Crohn's disease.

SEARCH METHODS: The following databases were searched from inception to September 16, 2014: PubMed, MEDLINE, EMBASE, and the Cochrane Library (CENTRAL). References and conference abstracts were searched to identify additional studies.

SELECTION CRITERIA: Randomized controlled trials (RCTs) trials in which monoclonal antibodies against IL-12/23p40 were compared to placebo or another active comparator in patients with active Crohn's disease were included. 

DATA COLLECTION AND ANALYSIS: Two authors independently screened  studies for inclusion and extracted data. Methodological quality was assessed using the Cochrane risk of bias tool. The primary outcome was failure to induce clinical remission, defined as a Crohn's disease activity index (CDAI) of < 150 points. Secondary outcomes included failure to induce clinical improvement, serious adverse events, and withdrawals due to adverse events. Clinical improvement was defined as decreases of > 70 or > 100 points in the CDAI from baseline. We calculated the risk ratio (RR) and 95% confidence intervals (95% CI) for each outcome. A fixed-effect model was used to pool data. Data were analyzed on an intention-to-treat basis. The overall quality of the evidence supporting the outcomes was evaluated using the GRADE criteria.

MAIN RESULTS: Four randomized controlled trials (n = 955 patients) met the inclusion criteria. A low risk of bias was assigned to all studies. The two briakinumab trials were not pooled due to differences in doses and time points for analysis. In both studies there was no statistically significant difference in remission rates. One study (n = 79) compared doses of 1 mg/kg and 3 mg/kg to placebo. In the briakinumab group 70% (44/63) of patients failed to enter clinical remission at 6 or 9 weeks compared to 81% (13/16) of placebo patients (RR 0.86, 95% CI 0.65 to 1.14). Subgroup analysis revealed no significant differences by dose. The other briakinumab study (n = 230) compared intravenous doses of 200 mg, 400 mg and 700 mg with placebo. Eighty-four per cent (154/184) of briakinumab patients failed to enter clinical remission at six weeks compared to 91% (42/46) of placebo patients (RR 0.92, 95% CI 0.83 to 1.03). Subgroup analysis revealed no significant differences by dose. GRADE analyses of the briakinumab studies rated the overall quality of the evidence for the outcome clinical remission as low due. Based on the results of these two studies the manufacturers of briakinumab stopped production of this medication. The two ustekinumab studies (630 patients) were pooled despite differences in intravenous doses (i.e. 1mg/kg, 3 mg/kg, 4.5 mg/kg, and 6 mg/kg), however the subcutaneous dose group was not included in the analysis, as it was unclear if subcutaneous was equivalent to intravenous dosing. There was no statistically significant difference in remission rates. At week six, 85% (356/420) of ustekinumab patients failed to enter remission compared to 89% (142/159) of placebo patients (RR 0.94, 95% CI 0.88 to 1.01). Subgroup analysis showed no statistically significant difference by dose. There were statistically significant differences in clinical improvement between ustekinumab and placebo-treated patients. In the ustekinumab group, 55% (230/420) of patients failed to improve clinically (i.e. 70-point decline in CDAI score), compared to 72% (115/159) of placebo patients (RR 0.75, 95% CI 0.66 to 0.86). Subgroup analysis revealed significant differences compared to placebo for the 1 mg/kg, 4.5 mg/kg and 6 mg/kg dosage subgroups. Similarly for a 100-point decline in CDAI, 62% (262/420) of patients in the ustekinumab group failed to improve clinically compared to 78% (124/159) of placebo patients (RR 0.79, 95% CI 0.71 to 0.89). Subgroup analysis showed a significant difference compared to placebo for the 4.5 mg/kg dose group. GRADE analyses of the ustekinumab studies rated the overall quality of the evidence for the outcomes clinical remission and clinical response as moderate. There were no statistically significant differences in the incidence of adverse events, serious adverse events or withdrawal due to adverse events. Sixty-seven per cent (316/473) of ustekinumab patients developed at least one adverse event compared to 73% (135/184) of placebo patients (RR 0.92, 95% CI 0.83 to 1.03). A GRADE analysis indicated that the overall quality of the evidence for this outcome was high. Six per cent (29/473) of ustekinumab patients had a serious adverse event compared to 8% (14/184) of placebo patients (RR 0.81, 95% CI 0.44 to 1.49). A GRADE analysis indicated that the overall quality of the evidence for this outcome was low. The most common adverse events in briakinumab patients were injection site reactions and infections. Infections were the most common adverse event in ustekinumab patients. Worsening of Crohn's disease and serious infections were the most common serious adverse events.

AUTHORS' CONCLUSIONS: Although we are uncertain about the efficacy of ustekinumab for induction of remission, moderate quality evidence suggests that ustekinumab may be effective for induction of clinical improvement in patients with moderate to severe CD. Due to small numbers of patients in dose subgroups the optimal dosage of ustekinumab is unclear. Briakinumab and ustekinumab appear to be safe. Due to sparse data we were unable to determine the risk of serious adverse events. Further studies are required to determine the efficacy and safety of ustekinumab in patients with moderate to severe CD. The results of three phase III trials that are currently underway will provide important new information.