Patent Term Extension For Biologics

• Published date: 17 February 2022
• Subject Matter: Intellectual Property, Food, Drugs, Healthcare, Life Sciences, Patent, Food and Drugs Law, Biotechnology & Nanotechnology
• Law Firm: Morrison & Foerster LLP
• Author: Ms Meghan McLean Poon, Nicholas G Vincent and Yuying You

Patent term extension (PTE) provides additional patent term for patents related to U.S. pharmaceutical products to compensate for the effective loss of patent term caused by delay during the drug approval process by the U.S. Food and Drug Administration (FDA).

To be eligible for PTE, a patent must claim a drug product, a method of using a drug product, or a method of manufacturing a drug product, and PTE is only available for the first approval of an "active ingredient."

The Federal Circuit has addressed the question of what constitutes an active ingredient¹ several times in the context of small molecules. For example, claims directed to a metabolite do not cover the active ingredient,² enantiomers of the same compound are different active ingredients,³ and different salts of the same compound are considered the same active ingredient for purposes of PTE.^[4] Although the Federal Circuit case law on small molecules is more developed, it is not clear how the court will apply the current case law and statutory framework to biologics including cell-based therapies and gene therapies.

Recent approval of a cell therapy, YESCARTA^', provides insight into considerations from the U.S. Patent & Trademark Office (USPTO) on what constitutes the active ingredient in the context of biologics.

The YESCARTA PTE application illustrates two challenges for defining the active ingredient in cell-based therapies to meet the first approval requirement.^[5] One challenge is how to define the active ingredient for certain cell-based therapies, where the product differs from patient to patient. Moreover, there is the related challenge of providing a detailed enough description of the active ingredient in the PTE application to allow the USPTO to distinguish the active ingredient of the product from previously approved active ingredients.

YESCARTA (Axicabtagene ciloleucel) is an immunotherapy approved to treat B-cell lymphomas. YESCARTA comprises autologous T cells (a type of immune cell that plays a crucial role in detecting and killing cancer cells) derived from an individual patient and engineered specifically to target the patient's cancer cells. The engineered T cells comprise: (1) T cells harvested from a patient and (2) a foreign protein (i.e., a chimeric antigen receptor (CAR)) specifically targeting a cell-surface protein. The T cells vary from patient to patient, but the CAR is the same for all patients. The T cells containing the CAR are responsible for the anti-tumor...