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Statistical and regulatory considerations in assessments of interchangeability of biological drug products.

Publication ,  Journal Article
Tóthfalusi, L; Endrényi, L; Chow, S-C
Published in: Eur J Health Econ
May 2014

When the patent of a brand-name, marketed drug expires, new, generic products are usually offered. Small-molecule generic and originator drug products are expected to be chemically identical. Their pharmaceutical similarity can be typically assessed by simple regulatory criteria such as the expectation that the 90% confidence interval for the ratio of geometric means of some pharmacokinetic parameters be between 0.80 and 1.25. When such criteria are satisfied, the drug products are generally considered to exhibit therapeutic equivalence. They are then usually interchanged freely within individual patients. Biological drugs are complex proteins, for instance, because of their large size, intricate structure, sensitivity to environmental conditions, difficult manufacturing procedures, and the possibility of immunogenicity. Generic and brand-name biologic products can be expected to show only similarity but not identity in their various features and clinical effects. Consequently, the determination of biosimilarity is also a complicated process which involves assessment of the totality of the evidence for the close similarity of the two products. Moreover, even when biosimilarity has been established, it may not be assumed that the two biosimilar products can be automatically substituted by pharmacists. This generally requires additional, careful considerations. Without declaring interchangeability, a new product could be prescribed, i.e. it is prescribable. However, two products can be automatically substituted only if they are interchangeable. Interchangeability is a statistical term and it means that products can be used in any order in the same patient without considering the treatment history. The concepts of interchangeability and prescribability have been widely discussed in the past but only in relation to small molecule generics. In this paper we apply these concepts to biosimilars and we discuss: definitions of prescribability and interchangeability and their statistical implementation; the relation between bioequivalence and interchangeability for small-molecule drug products; regulatory requirements and expectations of biosimilar products in various jurisdictions; possible statistical approaches to establish the similarity and interchangeability of biologic drug products; definition of other technical terms such as switchability and automatic substitution. The paper will be concluded with a discussion of the anticipated future use of interchangeability of biological drug products.

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Published In

Eur J Health Econ

DOI

EISSN

1618-7601

Publication Date

May 2014

Volume

15 Suppl 1

Issue

Suppl 1

Start / End Page

S5 / 11

Location

Germany

Related Subject Headings

  • United States
  • Therapeutic Equivalency
  • Humans
  • Health Policy & Services
  • Government Regulation
  • Europe
  • Drugs, Generic
  • Drug Approval
  • Canada
  • Biological Products
 

Citation

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ICMJE
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Tóthfalusi, L., Endrényi, L., & Chow, S.-C. (2014). Statistical and regulatory considerations in assessments of interchangeability of biological drug products. Eur J Health Econ, 15 Suppl 1(Suppl 1), S5-11. https://doi.org/10.1007/s10198-014-0589-1
Tóthfalusi, Lászlo, László Endrényi, and Shein-Chung Chow. “Statistical and regulatory considerations in assessments of interchangeability of biological drug products.Eur J Health Econ 15 Suppl 1, no. Suppl 1 (May 2014): S5-11. https://doi.org/10.1007/s10198-014-0589-1.
Tóthfalusi L, Endrényi L, Chow S-C. Statistical and regulatory considerations in assessments of interchangeability of biological drug products. Eur J Health Econ. 2014 May;15 Suppl 1(Suppl 1):S5-11.
Tóthfalusi, Lászlo, et al. “Statistical and regulatory considerations in assessments of interchangeability of biological drug products.Eur J Health Econ, vol. 15 Suppl 1, no. Suppl 1, May 2014, pp. S5-11. Pubmed, doi:10.1007/s10198-014-0589-1.
Tóthfalusi L, Endrényi L, Chow S-C. Statistical and regulatory considerations in assessments of interchangeability of biological drug products. Eur J Health Econ. 2014 May;15 Suppl 1(Suppl 1):S5-11.
Journal cover image

Published In

Eur J Health Econ

DOI

EISSN

1618-7601

Publication Date

May 2014

Volume

15 Suppl 1

Issue

Suppl 1

Start / End Page

S5 / 11

Location

Germany

Related Subject Headings

  • United States
  • Therapeutic Equivalency
  • Humans
  • Health Policy & Services
  • Government Regulation
  • Europe
  • Drugs, Generic
  • Drug Approval
  • Canada
  • Biological Products