Life Sciences Horizons Brochure 2025 - Flipbook - Page 40
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2025 Horizons Life Sciences and Health Care
Product sameness considerations for cellular and gene therapy products
Determining whether two cellular or gene therapy
products are the “same” for FDA regulatory purposes
continues to be an important and developing area of
the law. Product “sameness” has broad implications
on a number of regulatory decisions, including
exclusivity, priority review vouchers, patent term
extension, and approval actions. The complexity of
cellular and gene therapy products challenge FDA’s
existing regulatory framework and its traditional
notions of product sameness.
FDA issued guidance in 2021 establishing a general sameness
framework for determining whether gene therapy products are
the same for purposes of orphan drug exclusivity, which considers
both the transgene and vector. FDA implemented its framework
with the licensure of the cell-based gene therapy CAR-T product,
Breyanzi® (lisocabtagene maraleucel). In particular, FDA
determined that Breyanzi® was not the same as a previously
licensed CAR-T product for orphan drug purposes. In part, FDA
determined that the products used different transgene hinge and
transmembrane sequences. FDA also noted that the final cell
compositions of the products are different, and Breyanzi® is
administered at a defined ratio of T cell subsets.
FDA’s approach to cellular products will likely become more
important as FDA analyzes more complex cell-based gene therapy
products with differing cellular compositions. In a December 2023
draft guidance, FDA recognized that many cellular and gene
therapy products consist of a complex mixture of different cell
types where the contribution of each to the activity of the product
is difficult to determine. In these cases, FDA does not necessarily
consider the product to have multiple active ingredients. Rather,
the activity of the product is considered to be derived from
the totality of the mixture of the cells, and the mixture itself
is considered the active ingredient, not the individual
cellular components.
This past year, FDA applied its “sameness” framework in
the context of Priority Review Vouchers (PRVs), which require
a showing that the active ingredient has not been previously
approved. The issues involved products comprised of transduced
autologous CD34+ cells from patients. Of note, FDA denied a
PRV in one case based on the determination that the product
contained a previously approved active ingredient, illustrating
the ongoing complexity of “sameness” determinations for
such products.
Gary Veron
Partner
Washington, D.C.
Jason Conaty
Counsel
Washington, D.C.,
Los Angeles
Bryan Walsh
Senior Associate
Washington, D.C.
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