Adalimumab for maintenance of remission in Crohn's disease.

BACKGROUND Conventional medications for Crohn's disease (CD) include anti-inflammatory drugs, immunosuppressants and corticosteroids. If an individual does not respond, or loses response to first-line treatments, then biologic therapies such as tumour necrosis factor-alpha (TNF-α) antagonists such as adalimumab are considered for treating CD. Maintenance of remission of CD is a clinically important goal, as disease relapse can negatively affect quality of life. OBJECTIVES To assess the efficacy and safety of adalimumab for maintenance of remission in people with quiescent CD. SEARCH METHODS We searched the Cochrane IBD Group Specialized Register, CENTRAL, MEDLINE, Embase, and clinicaltrials.gov from inception to April 2019. SELECTION CRITERIA We considered for inclusion randomized controlled trials (RCTs) comparing adalimumab to placebo or to an active comparator. DATA COLLECTION AND ANALYSIS We analyzed data on an intention-to-treat basis. We calculated risk ratios (RRs) and corresponding 95% confidence intervals (95% CI) for dichotomous outcomes. The primary outcome was failure to maintain clinical remission. We define clinical remission as a Crohn's Disease Activity Index (CDAI) score of < 150. Secondary outcomes were failure to maintain clinical response, endoscopic remission, endoscopic response, histological remission and adverse events (AEs). We assessed biases using the Cochrane 'Risk of bias' tool. We used GRADE to assess the overall certainty of evidence supporting the primary outcome. MAIN RESULTS We included six RCTs (1158 participants). We rated four trials at low risk of bias and two trials at unclear risk of bias. All participants had moderate-to-severe CD that was in clinical remission. Four studies were placebo-controlled (1012 participants). Two studies (70 participants) compared adalimumab to active medication (azathioprine, mesalamine or 6-mercaptopurine) in participants who had an ileocolic resection prior to study enrolment. Adalimumab versus placebo Fifty-nine per cent (252/430) of participants treated with adalimumab failed to maintain clinical remission at 52 to 56 weeks, compared with 86% (217/253) of participants receiving placebo (RR 0.70, 95% CI 0.64 to 0.77; 3 studies, 683 participants; high-certainty evidence). Among those who received prior TNF-α antagonist therapy, 69% (129/186) of adalimumab participants failed to maintain clinical or endoscopic response at 52 to 56 weeks, compared with 93% (108/116) of participants who received placebo (RR 0.76, 95% CI 0.68 to 0.85; 2 studies, 302 participants; moderate-certainty evidence). Fifty-one per cent (192/374) of participants who received adalimumab failed to maintain clinical remission at 24 to 26 weeks, compared with 79% (149/188) of those who received placebo (RR 0.66, 95% CI 0.52 to 0.83; 2 studies, 554 participants; moderate-certainty evidence). Eighty-seven per cent (561/643) of participants who received adalimumab reported an AE compared with 85% (315/369) of participants who received placebo (RR 1.01, 95% CI 0.94 to 1.09; 4 studies, 1012 participants; high-certainty evidence). Serious adverse events were seen in 8% (52/643) of participants who received adalimumab and 14% (53/369) of participants who received placebo (RR 0.56, 95% CI 0.39 to 0.80; 4 studies, 1012 participants; moderate-certainty evidence) and withdrawal due to AEs was reported in 7% (45/643) of adalimumab participants compared to 13% (48/369) of placebo participants (RR 0.59, 95% CI 0.38 to 0.91; 4 studies, 1012 participants; moderate-certainty evidence). Commonly-reported AEs included CD aggravation, arthralgia, nasopharyngitis, urinary tract infections, headache, nausea, fatigue and abdominal pain. Adalimumab versus active comparators No studies reported failure to maintain clinical remission. One study reported on failure to maintain clinical response and endoscopic remission at 104 weeks in ileocolic resection participants who received either adalimumab, azathioprine or mesalamine as post-surgical maintenance therapy. Thirteen per cent (2/16) of adalimumab participants failed to maintain clinical response compared with 54% (19/35) of azathioprine or mesalamine participants (RR 0.23, 95% CI 0.06 to 0.87; 51 participants). Six per cent (1/16) of participants who received adalimumab failed to maintain endoscopic remission, compared with 57% (20/35) of participants who received azathioprine or mesalamine (RR 0.11, 95% CI 0.02 to 0.75; 51 participants; very low-certainty evidence). One study reported on failure to maintain endoscopic response at 24 weeks in ileocolic resection participants who received either adalimumab or 6-mercaptopurine (6-MP) as post-surgical maintenance therapy. Nine per cent (1/11) of adalimumab participants failed to maintain endoscopic remission compared with 50% (4/8) of 6-MP participants (RR 0.18, 95% CI 0.02 to 1.33; 19 participants). AUTHORS' CONCLUSIONS Adalimumab is an effective therapy for maintenance of clinical remission in people with quiescent CD. Adalimumab is also effective in those who have previously been treated with TNF-α antagonists. The effect of adalimumab in the post-surgical setting is uncertain. More research is needed in people with recent bowel surgery for CD to better determine treatment plans following surgery. Future research should continue to explore factors that influence initial and subsequent biologic selection for people with moderate-to-severe CD. Studies comparing adalimumab to other active medications are needed, to help determine the optimal maintenance therapy for CD.