Biosimilars: evidential standards for health technology assessment

A Systematic Literature Review of Gaps and Challenges in Value Assessment of Biosimilars: An ISPOR Special Interest Group Report

OBJECTIVES

This study aims to provide an overview of the gaps and challenges in the value assessment of biosimilars and to identify potential approaches to address them.

METHODS

A multidisciplinary, international team of biosimilar experts identified gaps and challenges. A systematic review was conducted of the peer-reviewed literature in PubMed, EMBASE, Web of Science Core Collection, EBSCOhost Business Source Complete; and of the gray literature. Preliminary results were presented at ISPOR conferences and this article benefited from 2 review rounds among ISPOR Biosimilar Special Interest Group members.

RESULTS

Given that a biosimilar is highly similar to its reference biologic, health technology assessment agencies should accept the comparability exercise approved by regulatory authorities and, thus, conduct a price comparison when biosimilar reimbursement is requested for the same indication as the reference biologic. If the reference biologic is not reimbursed or is not the standard of care, a full economic evaluation of the biosimilar versus a relevant comparator needs to be conducted. To date, little consideration has been given to specific challenges, such as how biosimilar value assessment can account for the nocebo effect, potential differences between biologic-naive and biologic-experienced patients, the availability of intravenous and subcutaneous administration forms or different administration devices for the same active compound, value-added services, and the contribution of biosimilars for generating health gain at the population level.

CONCLUSIONS

There is a need to gather further insights in the methodology of value assessment for biosimilars, and health technology assessment agencies need to develop more elaborate guidance on biosimilar value assessment in specific circumstances.

Economic evaluation of biosimilars for reimbursement purposes - what, when, how?

Background: Limited previous research and guidelines on the design of economic evaluation for biosimilars have led to unresolved methodological questions on how to assess biosimilars. Objectives: We want to raise awareness of and explore methodological issues for the economic evaluation of biosimilars. Methods: We relied on a literature review, exploratory interviews, and our experiences. Results and Conclusions: In the majority of cases in which reimbursement for a biosimilar is sought, it will not be necessary to conduct an economic evaluation, given that the reference product is already reimbursed and standard of care. If the latter is not the case, a full economic evaluation of the biosimilar versus standard of care is needed. This might also be needed in the case of differences in administration form or adherence (for example, due to a nocebo effect) and to take into account value-added services. The entry of biosimilars and of next-generation biological products should trigger a re-assessment of the entire product class. HTA bodies and reimbursement agencies should provide clear guidance on how to assess the value of a biosimilar in each of these circumstances.

Structural meta-analysis of regular human insulin in pharmaceutical formulations

We have studied regular acting, wild-type human insulin at potency of 100 U/mL from four different pharmaceutical products directly from their final finished formulation by the combined use of mass spectrometry (MS), dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), nuclear magnetic resonance (NMR), and single-crystal protein crystallography (PX). All products showed similar oligomeric assembly in solution as judged by DLS and SAXS measurements. The NMR spectra were compatible with well folded proteins, showing close conformational identity for the human insulin in the four products. Crystallographic assays conducted with the final formulated products resulted in all insulin crystals belonging to the R3 space group with two a dimer in the asymmetric unit, both with the B-chain in the T configuration. Meta-analysis of the 24 crystal structures solved from the four distinct insulin products revealed close similarity between them regardless of variables such as biological origin, product batch, country origin of the product, and analytical approach, revealing a low conformational variability for the converging insulin structural ensemble. We propose the use of MS, SAXS, NMR fingerprint, and PX as a precise chemical and structural proof of folding identity of regular insulin in the final, formulated product.

Biosimilar medicines and cost-effectiveness

Given that biosimilars are agents that are similar but not identical to the reference biopharmaceutical, this study aims to introduce and describe specific issues related to the economic evaluation of biosimilars by focusing on the relative costs, relative effectiveness, and cost-effectiveness of biosimilars. Economic evaluation assesses the cost-effectiveness of a medicine by comparing the costs and outcomes of a medicine with those of a relevant comparator. The assessment of cost-effectiveness of a biosimilar is complicated by the fact that evidence needed to obtain marketing authorization from a registration authority does not always correspond to the data requirements of a reimbursement authority. In particular, this relates to the availability of adequately powered equivalence or noninferiority studies, the need for comparative data about the effectiveness in a real-world setting rather than the efficacy in a structured setting, and the use of health outcome measures instead of surrogate endpoints. As a biosimilar is likely to be less expensive than the comparator (eg, the reference biopharmaceutical), the assessment of the cost-effectiveness of a biosimilar depends on the relative effectiveness. If appropriately designed and powered clinical studies demonstrate equivalent effectiveness between a biosimilar and the comparator, then a cost-minimization analysis identifies the least expensive medicine. If there are differences in the effectiveness of a biosimilar and the comparator, other techniques of economic evaluation need to be employed, such as cost-effectiveness analysis or cost-utility analysis. Given that there may be uncertainty surrounding the long-term safety (ie, risk of immunogenicity and rare adverse events) and effectiveness of a biosimilar, the cost-effectiveness of a biosimilar needs to be calculated at multiple time points throughout the life cycle of the product.

Similar biological medicinal products: lessons learned and challenges ahead

The first similar biological medicinal products (or biosimilars) were approved in the European Union (EU) in 2006 in accordance to a regulatory framework published by the European Commission in 2003 and 2004. The term ‘similar biological’ or biosimilar was preferred instead of the term ‘biogeneric’ as, in contrast to small molecules in chemical drugs, due to the size and complexity of biological products, additional safety and efficacy studies would be needed to establish comparability to a reference product. Several product-specific guidelines have already been developed by the European Medicines Agency describing the requirements to establish comparability on quality, safety and efficacy to the reference product and some others are currently under development. Even though the harmonized European regulatory framework for biosimilars there appear to be marked differences among the EU countries in the perception of the value and use of biosimilars. Several factors have been considered as challenges to their wide use such as concerns about their safety and efficacy, pharmacovigilance, interchangeability and substitution, market competition, and extrapolation of indications. A proper knowledge of these issues is required to ensure an appropriate place on the market for these products.

Generic and therapeutic substitutions in the UK: are they a good thing?

There is considerable interest and debate concerning the place of generic substitution (switching from a brand to generic product); and on therapeutic substitution, that is, switching to a cheaper, but apparently equivalent, product, usually within the drug class. Generic substitution by pharmacists is standard practice in UK hospital settings, and is being proposed for implementation in primary care. Although most prescriptions are already written generically (83% in the community in England in 2008), there are still cost savings that could be made if generic medicines are substituted against prescriptions written by branded name or by getting prescribers to adhere to advice to prescribe generically. Therapeutic substitution is more contentious, as direct evidence to support equivalence is normally lacking. However, the price differential between established drugs whose patents have expired and for which generics are available and newer, branded medicines within the same therapeutic class, makes therapeutic substitution an attractive application of cost-minimization analysis for the more efficient use of healthcare resources. Here we explore the tension that exists between the clinical appropriateness and safety of switching from an individual patient perspective and the consideration of value for money which is required to maximize population health from a health service perspective. Although substitution may affect individual patients (such as, for instance, reduced adherence, increased potential for medication error), it might be a price worth paying given the opportunity cost associated with the use of medicines that are clinically no better than cheaper alternatives.