Why Product Drift Is Not an Issue for Biosimilars/Biologics: Start the Same, Stay the Same.

Authors

Joseph P Park, Hyunhee Oh, Gillian R Woollett

Published in

BioDrugs : clinical immunotherapeutics, biopharmaceuticals and gene therapy. Jul 08, 2026. Epub Jul 08, 2026.

Abstract

Maintaining quality consistently after any manufacturing change is essential for all biologic medicines and is ensured through well-established scientific and regulatory principles. Over nearly 30 years, such manufacturing changes post-approval have been successfully managed and regulated with so-called comparability approaches, and these have become standard regulatory practice globally as ICH Q5E. A robust comparability assessment along with current good manufacturing practices (cGMP)-based regulatory control, maintains consistent product quality over the full lifetime of a product. The occurrence of 'quality drift' (also mislabelled as divergence) reflecting poor manufacturing control has been observed in some rare originator cases but not for biosimilars, nonetheless, highlighting the need for meticulous control. Despite this, hypothetical concerns regarding 'drift' between the originator product and biosimilar products continue to surface and are often portrayed as a unique risk created by biosimilars. This raises an important question: why are biosimilars associated with concerns about drift? Such concerns are unsupported by real-world evidence. Numerous biosimilar products have been maintaining consistent quality over extended periods, in some cases over a decade of use, thereby strengthening confidence in comparability methods and cGMP-based regulatory control. Such confidence then supports approved biosimilars, including interchangeable products, by showing that serial comparability assessments can occur independently for any given biologic. Consistent application of regulatory science to all biologics further demonstrates that good manufacturing control is independent of any specific regulatory pathway or business model.

PMID:
42420657
Bibliographic data and abstract were imported from PubMed on 09 Jul 2026.

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