Efficacy and Safety of Ontamalimab in Treating Inflammatory Bowel Disease: a Systematic Review and Meta-Analysis of Randomized Controlled Trials

Purpose of Review

Ontamalimab is an anti-MAdCAM-1 monoclonal antibody. It directly restricts the binding of α4β7 + lymphocytes and does not affect the homing of lymphocytes in the central nervous system. Thus, it diminishes adverse effects while blocking their migration into the gut. Several clinical trials have validated the efficacy and safety of ontamalimab for Crohn's disease and ulcerative colitis. However, to date, there is no meta-analysis on the topic. Hence, we are conducting this meta-analysis. Using R version R.3.3, we reported outcomes as risk ratios (RRs) or mean difference (MD) and confidence intervals (CIs). A P-value ≤ 0.05 is considered as statistically significant.

Recent Findings

The meta-analysis included a total of three studies with 1384 patients. In patients with ulcerative colitis, compared to placebo, ontamalimab had significantly improved clinical remission (RR = 2.17, 95% CI [1.42 to 3.32], P < 0.01), clinical response (RR = 1.79, 95% CI [1.35 to 2.38], P < 0.01), endoscopic response (RR = 2.27, 95% CI [1.55 to 3.31], P < 0.01) and mucosal healing (RR = 2.39, 95% CI [1.63 to 3.50], P < 0.01). No significant differences favoring ontamalimab or the placebo were found regarding safety outcomes. In patients with Crohn's disease, ontamalimab showed superiority over placebo in endoscopic response (RR = 2.00, 95% CI [1.08 to 3.70], P = 0.03). However, ontamalimab was associated with a higher incidence of serious adverse events, and study discontinuations were due to adverse events.

Summary

Ontamalimab has shown promising results, particularly in patients with moderate to severe ulcerative colitis, as evidenced by better clinical response and remission. However, questions remain about its long-term effectiveness and safety; hence, extended follow-up and more extensive studies are necessary.

Differential Effects of Ontamalimab Versus Vedolizumab on Immune Cell Trafficking in Intestinal Inflammation and Inflammatory Bowel Disease

BACKGROUND AND AIMS

The anti-MAdCAM-1 antibody ontamalimab demonstrated efficacy in a phase II trial in ulcerative colitis and results of early terminated phase III trials are pending, but its precise mechanisms of action are still unclear. Thus, we explored the mechanisms of action of ontamalimab and compared it to the anti-α4β7 antibody vedolizumab.

METHODS

We studied MAdCAM-1 expression with RNA sequencing and immunohistochemistry. The mechanisms of action of ontamalimab were assessed with fluorescence microscopy, dynamic adhesion and rolling assays. We performed in vivo cell trafficking studies in mice and compared ontamalimab and vedolizumab surrogate [-s] antibodies in experimental models of colitis and wound healing. We analysed immune cell infiltration under anti-MAdCAM-1 and anti-α4β7 treatment by single-cell transcriptomics and studied compensatory trafficking pathways.

RESULTS

MAdCAM-1 expression was increased in active inflammatory bowel disease. Binding of ontamalimab to MAdCAM-1 induced the internalization of the complex. Functionally, ontamalimab blocked T cell adhesion similar to vedolizumab, but also inhibited L-selectin-dependent rolling of innate and adaptive immune cells. Despite conserved mechanisms in mice, the impact of ontamalimab-s and vedolizumab-s on experimental colitis and wound healing was similar. Single-cell RNA sequencing demonstrated enrichment of ontamalimab-s-treated lamina propria cells in specific clusters, and in vitro experiments indicated that redundant adhesion pathways are active in these cells.

CONCLUSIONS

Ontamalimab has unique and broader mechanisms of action compared to vedolizumab. However, this seems to be compensated for by redundant cell trafficking circuits and leads to similar preclinical efficacy of anti-α4β7 and anti-MAdCAM-1 treatment. These results will be important for the interpretation of pending phase III data.

Anti-MADCAM therapy for ulcerative colitis

Introduction: The mucosal addressin cell adhesion molecule-1 (MAdCAM-1) plays a key role in the endothelial adhesion and migration of lymphocytes to sites of inflammation in inflammatory bowel disease. Therapies that target this pathway appear to be a promising therapeutic approach in the management of ulcerative colitis (UC).Areas covered: This review provides a summary of the preclinical and available clinical data on the safety and efficacy of ontamalimab (SHP647), a fully human monoclonal antibody that binds and inhibits the action of MAdCAM-1.Expert opinion: Intestinal immune cell trafficking is emerging as an important component in the pathogenesis of UC. Ontamalimab (SHP647) inhibits this process by preventing the binding of integrins found on the surface of lymphocytes and the endothelial ligand adhesion molecule MAdCAM-1. This monoclonal antibody has already demonstrated safety and efficacy in phase II clinical trials. Its targeted mechanism of action suggests a superior safety profile as compared with the current systemic immunosuppressive therapies. Results from the phase III trials are awaited to establish ontamalimab (SHP647) as a therapeutic option in the management of UC.

Targeting Endothelial Ligands: ICAM-1/alicaforsen, MAdCAM-1

Specific blockade of the endothelial ligands intercellular adhesion molecule-1 [ICAM-1] and mucosal addressin cell adhesion molecule [MAdCAM] involved in leukocyte recruitment to the site of inflammation as therapeutic targets in inflammatory bowel disease [IBD] has been recognized from their overexpression in the inflamed mucosa and successful intervention based on these ligands in preclinical animal models. Interventions to target ICAM-1 in human IBD are confined to the ICAM-1 anti-sense oligonucleotide alicaforsen. While results with parenteral formulations of alicaforsen in Crohn's disease have largely been negative, efficacy signals derived from studies with an enema formulation in ulcerative colitis and pouchitis are promising and have led to a Food and Drug Administration Fast-Track designation for the latter. A large phase III programme in pouchitis is underway. Phase II studies with the anti-MAdCAM-1 antibody [SHP647] delivered positive results in ulcerative colitis and anti-inflammatory signals in Crohn's disease. Furthermore, it was shown that SHP647 does not affect the number and composition of cells in cerebrospinal fluid, suggesting that the compound is not affecting immune surveillance in the central nervous system. In addition, both alicaforsen and SHP647 are promising compounds based on the clear safety profile observed so far.

PF-00547659 for the treatment of Crohn's disease and ulcerative colitis

INTRODUCTION

Gut-specific homing is mainly mediated by the expression of MAdCAM-1 on endothelial cells. An increase in MAdCAM-1 expression has been shown in patients with inflammatory bowel disease (IBD). Areas covered: PF-00547659 is a fully human monoclonal antibody (mAb) toward MAdCAM-1 on endothelial cells, blocking its binding with the α4β7 integrin on leukocytes. This review discusses the available data on effectiveness and safety of PF-00547659 in IBD. Expert opinion: A phase II study in moderate-to-severe ulcerative colitis (UC) patients, both naïve and previously exposed to anti-tumor necrosis factors, showed that PF-00547659 was superior to placebo for induction of remission, response, and mucosal healing at week 12. In contrast, preliminary results in a similar study in Crohn's disease (CD) did not show a superiority of PF-00547659, suggesting that PF-00547659 may have limited impact over CD outcomes. However, the time frame needed to evaluate clinical effectiveness of PF-00547659 may be longer in CD patients, given its transmural characteristic. In addition, it should be taken into consideration the possibility of incorporating new tools and more objective parameters in disease assessment that are proven to better correlate with inflammation. Future randomized-controlled trials are needed to confirm the efficacy of PF-00547659 in CD.

Anti-MAdCAM antibody (PF-00547659) for ulcerative colitis (TURANDOT): a phase 2, randomised, double-blind, placebo-controlled trial

BACKGROUND

PF-00547659 is a fully human monoclonal antibody that binds to human mucosal addressin cell adhesion molecule-1 (MAdCAM-1) to selectively reduce lymphocyte homing to the intestinal tract. We aimed to assess the efficacy and safety of PF-00547659 in patients with moderate to severe ulcerative colitis.

METHODS

This phase 2, randomised, double-blind, placebo-controlled clinical trial recruited patients aged 18-65 years from 105 centres in 21 countries, with a history (≥3 months) of active ulcerative colitis extending more than 15 cm beyond the anal verge (with a total Mayo score ≥6 and a Mayo endoscopic subscore ≥2) who had failed or were intolerant to at least one conventional therapy. Patients were stratified by previous anti-TNFα treatment, and randomly assigned by a computer-generated randomisation schedule to receive a subcutaneous injection of 7·5 mg, 22·5 mg, 75 mg, or 225 mg PF-00547659 or placebo at baseline, then every 4 weeks. Patients, investigators, and sponsors were blinded to the treatment. The primary endpoint was the proportion of patients achieving remission (total Mayo score ≤2 with no individual subscore >1 and rectal bleeding subscore ≤1) at week 12. The efficacy analysis included all patients who received at least one dose of the randomised treatment; the safety analysis was done according to treatment received. All p values were one-sided and multiplicity-adjusted. This study is registered with ClinicalTrials.gov, number NCT01620255.

FINDINGS

Between Nov 2, 2012, and Feb 4, 2016, we screened 587 patients; 357 were eligible and randomly assigned to receive placebo (n=73) or PF-00547659 at doses of 7·5 mg (n=71), 22·5 mg (n=72), 75 mg (n=71), or 225 mg (n=70). Remission rates at week 12 were significantly greater in three of four active-treatment groups than in the placebo group (2·7% [two of 73]): 7·5 mg (11·3% [eight of 71]), 22·5 mg (16·7% [12 of 72]), 75 mg (15·5% [11 of 71]), and 225 mg (5·7% [four of 70]). These rates corresponded to a stratum-adjusted (anti-TNFα-naive and anti-TNFα-experienced) risk difference versus placebo of 8·0% for 7·5 mg (90% CI 1·9 to 14, p=0·0425), 12·8% for 22·5 mg (5·6 to 19·9, p=0·0099), 11·8% for 75 mg (4·8 to 18·8, p=0·0119), and 2·6% for 225 mg (-1·2 to 6·4, p=0·1803). Four of 73 (5·5%) patients had a serious adverse event in the placebo group, ten of 71 (14·1%) in the 7·5 mg group, one of 70 (1·4%) in the 22·5 mg group, three of 73 (4·1%) in the 75 mg group, and three of 70 (4·3%) in the 225 mg group. No safety signal was observed for the study drug.

INTERPRETATION

PF-00547659 was safe and well tolerated in this patient population, and better than placebo for induction of remission in patients with moderate to severe ulcerative colitis. The greatest clinical effects were observed with the 22·5 mg and 75 mg doses.

FUNDING

Pfizer.

The Role of Integrin Expressing Cells in Modulating Disease Susceptibility and Progression (January 2016)

In this review we have summarized the role of gut homing molecules with a focus on the heterodimeric integrin α4β7 since the α4β7 has been shown to be important in modulating SIV transmission, disease susceptibility and progression. This review provides an overview of integrins, their structure and function to provide a general background upon which the role of the α4β7 integrin can best be understood. We also describe integrins and their cognate receptors and their potential role in modulating disease that we hope provides some food for thought on how such knowledge can be utilized for vaccine formulation.

Phosphotidylserine exposure and neutrophil extracellular traps enhance procoagulant activity in patients with inflammatory bowel disease

Inflammatory bowel disease (IBD)-associated thromboembolic event often lacks precise aetiology. The aim of this study was to investigate the contribution of phosphatidylserine (PS) exposure and neutrophil extracellular traps (NETs) towards the hypercoagulable state in IBD. We demonstrated that the levels of PS exposed MPs and the sources of MP-origin, platelets, erythrocytes, leukocytes and cultured endothelial cells (ECs) were higher in IBD groups than in healthy controls using flow cytometry and confocal microscopy. Wright-Giemsa and immunofluorescence staining demonstrated that the elevated NETs were released by activated IBD neutrophils or by control neutrophils treated with IBD sera obtained from patients with the active disease. MPs and MP-origin cells in IBD groups, especially in active stage, markedly shortened coagulation time and had increased levels of fibrin, thrombin and FXa production as assessed by coagulation function assays. Importantly, we found that on stimulated ECs, PS rich membranes provided binding sites for FXa and FVa, promoting fibrin formation while TNF blockage or IgG depletion attenuated this effect. Treatment of control neutrophils with TNF and isolated IgG from PR3-ANCA-positive active IBD patients also resulted in the release of NETs. Blockade of PS with lactadherin prolonged coagulation time, decreased fibrin formation to control levels, and inhibited the procoagulant enzymes production in the MPs and MP-origin cells. NET cleavage by DNase I partly decreased PCA in IBD or stimulated neutrophils. Our study reveals a previously unrecognised link between hypercoagulable state and PS exposure or NETs, and may further explain the epidemiological association of thrombosis within IBD patients.

Progress with anti-tumor necrosis factor therapeutics for the treatment of inflammatory bowel disease

Anti-tumor necrosis factor (TNF) therapy is a valid, effective and increasingly used option in inflammatory bowel disease management. Nevertheless, further knowledge and therapeutic indications regarding these drugs are still evolving. Anti-TNF therapy may be essential to achieve recently proposed end points, namely mucosal healing, prevention of bowel damage and prevention of patient's disability. Anti-TNF drugs are also suggested to be more effective in early disease, particularly in early Crohn's disease. Moreover, its efficacy for prevention of postoperative recurrence in Crohn's disease is still debated. Costs and adverse effects, the relevance of drug monitoring and the possibility of anti-TNF therapy withdrawal in selected patients are still debated issues. This review aimed to describe and discuss the most relevant data about the progress with anti-TNF therapy for the management of inflammatory bowel disease.