No abstract

Many of the best-selling 'blockbuster' biological medicinal products are, or will soon be, facing competition from similar biological medicinal products (biosimilars) in the EU. Biosimilarity is based on the comparability concept, which has been used successfully for several decades to ensure close similarity of a biological product before and after a manufacturing change. Over the last 10 years, experience with biosimilars has shown that even complex biotechnology-derived proteins can be copied successfully. Most best-selling biologicals are used for chronic treatment. This has triggered intensive discussion on the interchangeability of a biosimilar with its reference product, with the main concern being immunogenicity. We explore the theoretical basis of the presumed risks of switching between a biosimilar and its reference product and the available data on switches. Our conclusion is that a switch between comparable versions of the same active substance approved in accordance with EU legislation is not expected to trigger or enhance immunogenicity. On the basis of current knowledge, it is unlikely and very difficult to substantiate that two products, comparable on a population level, would have different safety or efficacy in individual patients upon a switch. Our conclusion is that biosimilars licensed in the EU are interchangeable.

In recent years, marketing of highly innovative and costly biologics improved the management of high-burden diseases such as autoimmune diseases, cancers, and chronic renal failure. Several widely prescribed biologics have recently lost or will shortly lose their patents, thus opening avenues to the marketing of a growing number of biosimilars worldwide, which are products similar in terms of quality, safety, and efficacy to already licensed reference products, thus allowing for potential savings in pharmaceutical expenditure. Numerous debates about the interchangeability between biosimilars and reference products are still ongoing, owing to concerns about potential immunogenicity raised by switching, which may cause a lack of effect and toxicity. Patients successfully treated with biologic therapy may theoretically receive biosimilars to contain costs, if reference product and related biosimilar are judged as interchangeable. However, the positions of regulatory agencies on the interchangeability and automatic substitution of biologics with biosimilars are very different. The benefit-risk profile of biosimilars has been often questioned by clinicians owing to the limited amount of pre-marketing information on clinical efficacy and safety, despite biosimilarity being based on a comparability exercise with the reference product to gain the biosimilar approval. Nevertheless, after more than 10 years of marketing from the first biosimilar approval in Europe, no proof of differences in terms of the safety profile of biosimilars and originators has been reported. In this context, post-marketing evaluation of both biologics and biosimilars safety profiles through analyses from spontaneous reporting databases and claims databases is crucial. An important issue for the pharmacovigilance of biologics concerns the traceability, indicating the brand name and batch number in spontaneous adverse drug reaction reports, but this requirement is not frequently addressed. This review aims to provide an overview of the characteristics and potential challenges in the safety profile assessment of biologics with a focus on the post-marketing setting.

The existing systems ensure the traceability of biologicals down to the manufacturer within pharmacy records, but do not support the routine recording of batch information. Expected changes in supply chain standards provide opportunities to systematically record detailed exposure information. Spontaneous reporting systems are the most vulnerable link in ensuring traceability, due to the manual nature of data transfer. Efforts to improve the traceability should, in the short term, be focused toward encouraging health professionals and patients to systematically record and report detailed exposure information. Long-term solutions lie in expanding the accessibility to, and increasing the electronic exchange of exposure data.

Biologicals are established treatment options that require pharmacovigilance adapted to their specific nature, including the need for products to be identifiable up to the specific manufacturer in reports of adverse drug reactions ( ADR s). This study explored the identifiability of 10 classes of similar and related biologicals up to the level of the manufacturer in ADR reports received from European clinical practice between 2011 and June 2016. Adequate identifiers were reported for 96.7% of the suspected biologicals, ranging from 89.5% for filgrastim to 99.8% for interferon beta‐1a. The product identifiability remained consistently high over time for classes of biologicals for which biosimilars were introduced during follow‐up. The overall batch traceability was, however, only ensured for 20.5% of the suspected biologicals and needs further improvement. This study shows that the European system for identification of ADR s to the level of the manufacturer is robust, allowing for the timely detection of potential product‐specific safety signals for biologicals.