Risk-benefit analysis of adalimumab versus traditional non-biologic therapies for patients with Crohn's disease

Natalizumab in the treatment of Crohn's disease patients

INTRODUCTION

Amongst the available therapies for moderate to severe Crohn's disease (CD) patients who are refractory to conventional therapy, anti-TNF blockers are the most effective biological treatment option. However, many patients experience a primary or secondary non-response to anti-TNF therapy, creating the need for alternative biological drugs that target different mechanisms of action and inflammatory pathways. Natalizumab, the first non-anti-TNF biological drug to be approved for treatment of CD patients, is a recombinant humanized antibody that targets the α₄-subunit of both α₄β₁ and α₄β₇ integrins, thus preventing activated leukocyte homing to the intestinal mucosa. Areas covered: This article summarizes the pathophysiological background and the efficacy and safety data of natalizumab, as well as the regulatory issues surrounding it. Expert opinion: Natalizumab represents an effective therapy for refractory CD patients. However, the rare but serious event of progressive multifocal leukoencephalopathy occurrence has compromised its widespread use. The subsequent advent of more specific anti-integrin drugs (i.e. vedolizumab) that carry a more favorable safety profile further reduces the clinical indications for natalizumab. The regulatory process for natalizumab distribution and monitoring in the US may provide a forum for discussion on how to optimally manage use of drugs that offer clinical benefits to patients, while minimizing associated risks.

Integration of PKPD relationships into benefit-risk analysis

AIM

Despite the continuous endeavour to achieve high standards in medical care through effectiveness measures, a quantitative framework for the assessment of the benefit-risk balance of new medicines is lacking prior to regulatory approval. The aim of this short review is to summarise the approaches currently available for benefit-risk assessment. In addition, we propose the use of pharmacokinetic-pharmacodynamic (PKPD) modelling as the pharmacological basis for evidence synthesis and evaluation of novel therapeutic agents.

METHODS

A comprehensive literature search has been performed using MESH terms in PubMed, in which articles describing benefit-risk assessment and modelling and simulation were identified. In parallel, a critical review of multi-criteria decision analysis (MCDA) is presented as a tool for characterising a drug's safety and efficacy profile.

RESULTS

A definition of benefits and risks has been proposed by the European Medicines Agency (EMA), in which qualitative and quantitative elements are included. However, in spite of the value of MCDA as a quantitative method, decisions about benefit-risk balance continue to rely on subjective expert opinion. By contrast, a model-informed approach offers the opportunity for a more comprehensive evaluation of benefit-risk balance before extensive evidence is generated in clinical practice.

CONCLUSIONS

Benefit-risk balance should be an integral part of the risk management plan and as such considered before marketing authorisation. Modelling and simulation can be incorporated into MCDA to support the evidence synthesis as well evidence generation taking into account the underlying correlations between favourable and unfavourable effects. In addition, it represents a valuable tool for the optimization of protocol design in effectiveness trials.

Inflammatory bowel disease meta-evidence and its challenges: is it time to restructure surgical research?

AIM

The aim of this study was to compare the methodological quality and input paper characteristics of systematic reviews and meta-analyses reported in the medical and surgical literature by performing a systematic 'overview of reviews'. Ulcerative colitis (UC) and Crohn's disease (CD) were used as the framework for this comparison as they are relatively common serious conditions, with both medical and surgical options for therapy.

METHOD

Medline, Embase, CINHAL and the Cochrane Database were searched to November 2013. Eligible papers were systematic reviews or meta-analyses that considered a question of therapy in CD or UC. Two independent reviewers selected the papers, extracted the data and scored their methodology using the AMSTAR scoring system. The papers were categorized into medical therapy (M), surgical therapy (S) or medical and surgical therapy (MS) groups. Following retrieval of the sample of meta-evidence papers, the original input studies used in their creation were identified and a search of Medline, Embase, CINHAL and the Cochrane Database was performed. A team of researchers then examined the collection of papers for bibliographic and financial information.

RESULTS

Five hundred papers were identified in the meta-evidence search, of which 118 were deemed eligible. There was a difference in the AMSTAR-rated average quality of the papers between the S and M group (S 7.36 vs M 8.75, P = 0.01). On average S papers were published in journals with a lower impact factor (S 3.26, M 5.04, MS 5.30, P < 0.001). S papers also showed more heterogeneity (I(2) ; S 37%, M 24%, MS 10%, P < 0.001). Some 25% of S meta-analyses used data-sets with significant heterogeneity (I(2) > 75%), compared with 8% of M meta-analyses and 3% of the MS meta-analyses. Some 5% of S papers were done on data sets that had I(2) values > 90%. There was no difference in the average number of papers assessed in each group, the average number of patients per meta-paper, the average time covered by the reviews, the average number of papers considered within each meta-analysis, or the average number of patients considered within each meta-analysis. Considering the conclusions of each meta-analysis, S meta-evidence was 50% more likely than M meta-evidence to be unable to make recommendations for practice. A total of 1499 original input papers were identified, of which 283 were used in more than one review. Within the non-repeated papers (n = 1023) the average impact factor within the S group was lower than that of the M and the MS groups (3.720 vs 11.230 vs 7.563, respectively; ANOVAP < 0.001). M papers had higher rates of pharmaceutical sponsorship than S papers (M 56% vs S 1%) and twice the level of government support (M 16% vs S 8%). Of note, 21% of M papers had corporate sponsorship but did not list any conflict of interest.

CONCLUSION

Compared with M meta-analyses, S meta-analyses in the UC and CD domain are more likely to be of poorer methodological quality, are of a greater degree of heterogeneity and less often offer a positive conclusion. The papers used to generate meta-evidence in M papers have a greater degree of corporate and government sponsorship, and are more likely to come from journals with higher impact factors.

Safety considerations when using anti-TNFα therapy to treat Crohn's disease

INTRODUCTION

Over the past decade, the introduction of a new class of anti-TNFα drugs has dramatically changed the approach taken to the management of Crohn's disease (CD). An increasing number of patients are receiving treatment with these advanced biological therapies, and the risk of adverse events that may be associated with their use must be carefully evaluated.

AREAS COVERED

Safety data about the three anti-TNFα drugs currently approved for use in CD patients (infliximab, adalimumab, and certolizumab pegol) is critically evaluated, including data coming from randomized clinical trials and post-marketing reports. Possible side effects of anti-TNFα agents are presented as drug-, class- and disease-specific adverse events. Management strategies to minimize the occurrence of side effects are summarized.

EXPERT OPINION

The safety profile of the three anti-TNFα drugs approved for clinical use in CD patients appears to be comparable among drugs. Data from clinical trials and a growing body of information from post-marketing surveillance indicate that anti-TNFα agents are generally safe, and that most of the observed side effects are mild and easily manageable. Nonetheless, serious short- and long-term adverse events may occur. Accurate selection of patients, careful pre-treatment evaluation, and regular follow-up during therapy could potentially reduce the rate of adverse events related to the use of anti-TNFα drugs.

Therapeutic human monoclonal antibodies in inflammatory diseases

Monoclonal antibodies (mAbs) are antibodies of a single antigen specificity produced by identical immune cells, i.e., clones of a common germ cell. They offer unprecedented opportunities to drug development because of their ability to target almost any cell surface or secreted molecule with remarkable efficacy and safety. In this chapter, the application of human mAbs in the treatment of inflammatory diseases is reviewed. We discuss in detail several mAb-based drugs such as anti-tumor necrosis factor (anti-TNF), anti-interleukin-1 (anti-IL-1) receptor, anti-IL-6 receptor, anti-α4 integrin subunit, and anti-CD20 agents, all of which have been documented by clinical trials to be efficacious and have been approved for the therapy of several inflammatory and immune diseases, including rheumatoid arthritis, Crohn's disease, ulcerative colitis, spondyloarthropathies, juvenile arthritis, psoriasis, psoriatic arthritis, and others. These novel drugs can be used either as a monotherapy or in combination with other conventional therapeutic modalities, particularly if the disease under treatment is refractory to therapy using solely conventional techniques. As a large variety of mAb-based agents targeting a plethora of cytokines, chemokines, adhesion and co-stimulatory molecules, receptors, as well as diverse cell types, are presently under investigation, the therapeutic armamentarium of the clinician is expected to greatly broaden in the near future, providing improved patient care for a wide range of devastating diseases of our times.

The chronic gastrointestinal consequences associated with campylobacter

Campylobacteriosis is a leading cause of acute infectious diarrhea in the developing world, where it causes considerable mortality, and in developed countries, where it accounts for significant healthcare and other costs. Evidence has emerged from basic science, clinical, and epidemiological domains that suggests that Campylobacter infection is not limited to acute illness but is also involved in the development of well-described extraintestinal sequelae, such as the Guillain-Barré syndrome and reactive arthritis, and may also contribute to the pathogenesis of chronic gastrointestinal conditions. This review will focus on the role of Campylobacter infection as a risk factor for the development of chronic gastrointestinal sequelae, such as functional gastrointestinal disorders, with which irritable bowel syndrome has been most frequently associated, inflammatory bowel disease, and celiac disease.

Advances in treatment of Crohn's disease with adalimumab

Adalimumab is a subcutaneously administered, fully humanized anti-TNF-α monoclonal IgG1 antibody and represents an important new therapeutic option for the treatment of Crohn's disease for its convenient mode of administration and less adverse events. Adalimumab is effective in inducing and maintaining clinical response and remission in patients with moderate to severe Crohn's disease, which permits to spare potential steroid usage, achieve mucosal healing and improve the quality of life in these patients. Adalimumab has also been shown to be beneficial to patients who lose response or are intolerant to infliximab and to promote the closure of the fistula orifice. This article reviews the recent advances in the treatment of Crohn's disease with adalimumab.