Review article: pharmacological aspects of anti-TNF biosimilars in inflammatory bowel diseases

BACKGROUND

Anti-tumour necrosis factor (anti-TNF) monoclonal antibodies have shown efficacy in inflammatory bowel diseases (IBD). As these therapies lose patent protection, biosimilar versions of the originator products are being developed, such as the infliximab biosimilar CT-P13; however, some uncertainty exists regarding their pharmacology in IBD.

AIM

To review the literature on anti-TNF biosimilars focusing on pharmacokinetics, pharmacodynamic properties and comparative effectiveness, related to their use in IBD.

METHODS

A PubMed literature search was performed using the following terms individually or in combination: 'biosimilars,' 'CT-P13,' 'Crohn's disease,' 'inflammatory bowel disease,' 'ulcerative colitis,' 'anti-TNFα therapy,' 'infliximab,' 'adalimumab,' 'pharmacokinetics,' 'immunogenicity.'

RESULTS

Bioequivalence of CT-P13 and infliximab was shown in ankylosing spondylitis (AS) and therapeutic equivalence in rheumatoid arthritis (RA). Preliminary results of CT-P13 in IBD come from small post-marketing registries and case series with a relatively short-term follow-up period and suggest comparable efficacy and safety to infliximab. Inter- and intra-individual differences in exposure and response are well known for the original molecules but dosing regimens and concomitant medications are different for RA compared to IBD, limiting the ability to translate some of the pharmacology data in RA to IBD. Uncertainty exists about cross-reactivity of anti-drug antibodies and whether similar exposure-response relationships will be observed for biosimilars and efficacy thresholds for therapeutic drug monitoring can be used interchangeably.

CONCLUSIONS

It is likely that biosimilars will be widely used for the treatment of IBD due to their cost savings and comparable efficacy. Nevertheless, robust post-marketing studies and pharmacovigilance are warranted in the coming years.

Biosimilars in the therapy of inflammatory bowel diseases

A biosimilar is a copy of an approved biological medicine whose patent protections have expired. Biosimilars of antibodies to tumour necrosis factor α (TNFα) are becoming important in the treatment of inflammatory bowel diseases (IBD). The first one introduced commercially is an infliximab biosimilar. The aim of this study was to provide an overview of anti-TNFα biosimilars. The literature on biosimilars of monoclonal anti-TNFα antibodies was reviewed, including their manufacture and approval pathways, concerns about efficacy, safety, immunogenicity, extrapolation, switching and labelling. Previous experience with biosimilars of epoetin and other growth factors was also reviewed. The infliximab biosimilar CT-P13 was the first biosimilar monoclonal antibody registered for the treatment of IBD. The major advantage of biosimilars is the reduced cost of therapy. Concerns have arisen, however, about the efficacy and safety of CT-P13 in IBD, the extrapolation of results from rheumatologic trials to IBD and the free interchangeability of CT-P13 with infliximab. Experience with simple peptide biosimilars, such as epoetins and growth factors, has generally been positive, with these biosimilars having similar efficacy and safety as the original products, although immunogenicity remains a major concern. Upcoming postregistration studies will address concerns on biosimilars in IBD, including their efficacy, safety, immunogenicity, switching and interchangeability. Biosimilars active against the same epitopes, but with improved pharmacokinetic properties that enhance their efficacy and/or safety, may be the next stage in the development of biosimilars. Anti-TNFα biosimilars represent promising new treatment options for patients with IBD. However, data on their efficacy and safety in IBD are needed.

Role of public standards in the safety and efficacy of biologic medicines

In this report, we emphasize the importance of public monographs with reference materials, coupled with careful process and change control and attention to GMPs, as a means of advancing access to good quality, safe, and effective medicines, with emphasis on available and incoming biologic medicines. With adequate control of articles covered by a monograph, these public standards can form the basis for a global public quality platform that covers reference products, non-interchangeable reference products, biosimilars, and interchangeable biosimilars. Working collaboratively with all stakeholders, new approaches allow these public standards to emerge nationally and globally in a timely way. Yet, there are increasing limitations in the availability of public standards for biologic medicines, which may reverse many decades of progress. Solutions are considered in this report.

Is the decision on the use of biosimilar growth hormone based on high quality scientific evidence? - a systematic review

BACKGROUND

The authors carried out a systematic and critical review of the scientific literature regarding the possible development of neutralising antibodies developed in patients treated with growth hormone biosimilars (defined as a drug expected to be similar to the originator or original pharmaceutical -European Medicines Agency) as compared to the reference drug. As a consequence, we discovered two major issues, namely, the poor quality of the comparative clinical trials and the poor quality of the antibody assays used during the trials.

METHODS

The literature review was performed according to the principle of the Cochrane Collaboration and SBU. The electronic literature search included the databases PubMed, EMBASE and The Cochrane Library up to December 2012. Two independent reviewers assessed abstracts and full-text articles.

RESULTS

The search identified 1,553 abstracts related to the subject. Only six articles contained data on biosimilar growth hormone or antibody results obtained with appropriate methods. None of the studies fulfilled the criteria for high quality randomised controlled trials. Qualitative rather than quantitative assays were used for monitoring antibody formation.

CONCLUSIONS

It is our firm opinion , that since biosimilars are not identical, emphasis must be placed on the quality of the comparative clinical trials performed and the quality of the analytical studies in order to guarantee patient safety. Clinical trials should follow established quality rules for controlled comparative randomised clinical trials. A whole set of new guidelines is required.

Bioanalytical challenges of biosimilars

Biologics such as monoclonal antibodies and recombinant proteins represent a significant portion of the pharmaceutical market. With many of the first generation biologics’ patents expiring, an increasing number of biosimilars will be submitted for approval in the near future. The successful development of a biosimilar requires the demonstration of biosimilarity in terms of efficacy, safety and purity to an innovator-approved product. While regulatory frameworks have been established for the approval of biosimilars in several countries, there is not an established guidance for bioanalytical testing of biosimilars. Although there are regulatory guidances and White Papers on testing requirements for biologics in general, there is a need to address the bioanalytical challenges and solutions that apply specifically to the analysis of biosimilars in biological samples. This paper will focus on components of the PK and immunogenicity assays that are critical to biosimilar drug development.