Anti-integrin drugs in clinical trials for inflammatory bowel disease (IBD): insights into promising agents.

INTRODUCTION: Despite huge and increasing developments in the treatment of inflammatory bowel disease (IBD), a significant percentage of patients with Crohn's disease (CD) and ulcerative colitis (UC) is still in need of an effective and safe therapeutic option. Tackling the trafficking of leukocytes specifically within or directed to the inflamed gut appears to be a particularly promising strategy, and several new anti-integrin agents are currently under investigation in clinical trials. AREAS COVERED: This review summarizes efficacy and safety data from phase 1, 2 and 3 clinical trials on investigational drugs, including monoclonal antibodies (etrolizumab, abrilumab, ontamalimab) and oral small molecules (AJM300, PTG-100). It also discusses the future perspectives for the treatment of IBD patients with this class of agents. EXPERT OPINION: The pipeline of anti-integrin agents is well assorted, and it is reasonable to expect that some will be introduced in the market soon. Among the most exciting features of this class are the gut selectivity, the convenient subcutaneous and oral administrations and the reassuring safety profiles. Most of the new anti-integrins seem to improve outcomes in UC but not in CD, however these data are far from definitive and several pivotal trials are still under way.

Efficacy and safety of abrilumab, an α4ß7 integrin inhibitor, in Japanese patients with moderate-to-severe ulcerative colitis: a phase II study.

BACKGROUND/AIMS: Inhibition of α4ß7 integrin has been shown to be effective for induction and maintenance therapy in patients with ulcerative colitis (UC). We investigated the effects of varying doses of the α4ß7 inhibitor abrilumab in Japanese patients with moderate-to-severe UC despite conventional treatments. METHODS: In this randomized, double-blind, placebocontrolled study, 45 UC patients were randomized to abrilumab 21 mg (n=11), 70 mg (n=12), 210 mg (n=9), or placebo (n=13) via subcutaneous (SC) injection for 12 weeks. The double-blind period was followed by a 36-week open-label period, in which all patients received abrilumab 210 mg SC every 12 weeks, and a 28-week safety follow-up period. The primary efficacy variable was clinical remission at week 8 (total Mayo score ≤2 points with no individual subscore >1 point). RESULTS: Clinical remission at week 8 was 4 out of 31 (12.9%) overall in the abrilumab groups versus 0 out of 13 in the placebo group (abrilumab 21 mg, 1/10 [10.0%]; 70 mg, 2/12 [16.7%]; 210 mg, 1/9 [11.1%]). In both the double-blind and open-label periods, fewer patients in the abrilumab groups experienced ≥1 adverse event compared with those in the placebo group. There were no cases of progressive multifocal leukoencephalopathy and no deaths. CONCLUSIONS: Abrilumab 70 mg and 210 mg yielded numerically better results in terms of clinical remission rate at Week 8 than placebo, with the 210 mg dose showing more consistent treatment effects. Abrilumab was well tolerated in Japanese patients with UC.

Efficacy and Safety of Abrilumab in a Randomized, Placebo-Controlled Trial for Moderate-to-Severe Ulcerative Colitis.

BACKGROUND & AIMS: The α4ß7 integrin is a validated target in inflammatory bowel disease. This randomized, phase 2b, placebo-controlled, double-blind study evaluated the efficacy and safety of the anti-α4ß7 antibody abrilumab in patients with moderate-to-severe ulcerative colitis despite treatment with conventional therapies. METHODS: Patients (total Mayo Score 6-12, recto-sigmoidoscopy score ≥2) with inadequate response or intolerance to conventional therapies were randomized to receive subcutaneous abrilumab (7, 21, or 70 mg) on day 1, weeks 2 and 4, and every 4 weeks; abrilumab 210 mg on day 1; or placebo. The primary end point was remission (total Mayo Score ≤2 points, no individual sub-score >1 point) for the 2 highest dosages at week 8. Key secondary end points were response and mucosal healing (centrally read) at week 8. RESULTS: For 354 patients who received ≥1 dose of investigational product (placebo, n = 116; 7 mg, n = 21; 21 mg, n = 40; 70 mg, n = 98; 210 mg, n = 79), non-adjusted remission rates at week 8 were 4.3%, 13.3%, and 12.7% for the placebo and abrilumab 70-mg and 210-mg groups, respectively (P < .05 for 70 and 210 mg vs placebo); odds of achieving remission were significantly greater with abrilumab 70 mg (odds ratio 3.35; 90% CI 1.41-7.95; P = .021) and 210 mg (odds ratio 3.33; 90% confidence interval 1.34-8.26; P = .030) than with placebo. Response and mucosal healing rates with these dosages also were significantly greater than with placebo. Higher baseline α4ß7 levels on naïve CD4+ T cells were a prognostic indicator for overall outcome, but not a predictive biomarker of abrilumab response. There were no cases of progressive multifocal leukoencephalopathy or deaths. CONCLUSIONS: Abrilumab treatment for 8 weeks induced remission, clinical response, and mucosal healing in patients with moderate-to-severe ulcerative colitis. ClinicalTrials.gov, number NCT01694485.

Efficacy and safety of abrilumab, an α4β7 integrin inhibitor, in Japanese patients with moderate-to-severe ulcerative colitis: a phase II study

BACKGROUND/AIMS: Inhibition of α4β7 integrin has been shown to be effective for induction and maintenance therapy in patients with ulcerative colitis (UC). We investigated the effects of varying doses of the α4β7 inhibitor abrilumab in Japanese patients with moderate-to-severe UC despite conventional treatments. METHODS: In this randomized, double-blind, placebo-controlled study, 45 UC patients were randomized to abrilumab 21 mg (n=11), 70 mg (n=12), 210 mg (n=9), or placebo (n=13) via subcutaneous (SC) injection for 12 weeks. The double-blind period was followed by a 36-week open-label period, in which all patients received abrilumab 210 mg SC every 12 weeks, and a 28-week safety follow-up period. The primary efficacy variable was clinical remission at week 8 (total Mayo score ≤2 points with no individual subscore >1 point). RESULTS: Clinical remission at week 8 was 4 out of 31 (12.9%) overall in the abrilumab groups versus 0 out of 13 in the placebo group (abrilumab 21 mg, 1/10 [10.0%]; 70 mg, 2/12 [16.7%]; 210 mg, 1/9 [11.1%]). In both the double-blind and open-label periods, fewer patients in the abrilumab groups experienced ≥1 adverse event compared with those in the placebo group. There were no cases of progressive multifocal leukoencephalopathy and no deaths. CONCLUSIONS: Abrilumab 70 mg and 210 mg yielded numerically better results in terms of clinical remission rate at Week 8 than placebo, with the 210 mg dose showing more consistent treatment effects. Abrilumab was well tolerated in Japanese patients with UC.

Anti-integrin therapy for inflammatory bowel disease.

In inflammatory bowel disease (IBD), tumor necrosis factor plays an important role in mediating inflammation, but several other pathways are also involved in eliciting an inflammatory response. One such pathway is the invasion of the intestinal mucosa by leukocytes. Leukocytes within the systemic circulation move to sites of inflammation, and blocking this pathway could be an important treatment strategy for IBD. Anti-integrin therapy blocks the action of integrin on the surface of circulating immune cells and endothelial cell adhesion molecules, thereby inhibiting the interactions between leukocytes and intestinal blood vessels. Natalizumab, which acts on α4-integrin, was the first such drug to be approved for Crohn's disease, but its use is limited due to the risk of progressive multifocal leukoencephalopathy. Vedolizumab produces few systemic adverse effects because it acts on gut-trophic α4ß7 integrin, and has been approved and is being used to treat IBD. Currently, several anti-integrin drugs, including etrolizumab, which acts on ß7-integrin, and PF-00547569, which targets mucosal addressin cell adhesion molecule-1, are undergoing clinical trials and the results are being closely watched.