Authored by: Jeremy J. Gustrowsky
In a recent decision, the Federal Circuit affirmed the validity of Jadi Cell, LLC’s U.S. Patent No. 9,803,176, which covers a method for obtaining stem cells from the subepithelial layer of mammalian umbilical cord tissue. The patent describes a two-step process: placing the subepithelial layer in direct contact with a growth substrate and then culturing it to produce cells with a specific marker profile. Restem, LLC had challenged the patent in an inter partes review, arguing that earlier scientific literature (referred to as “Majore”) either anticipated or made the claimed invention obvious.
A key issue in the case was how to interpret the patent’s language, especially the terms “placing” and “isolated cell.” The court agreed with the Patent Trial and Appeal Board’s (PTAB) approach, finding that “placing” did not require extra steps beyond what was claimed, and that “isolated cell” should be understood as referring to a population of cells, not just a single cell. This interpretation was supported by both the patent’s wording and its prosecution history, where the applicant had accepted the examiner’s view that the claims were about cell populations.
Restem’s main argument was that the prior art inherently produced the same type of stem cells as described in the patent, simply by following similar steps. However, the court found substantial evidence that the prior art process did not always result in cells with the exact marker profile required by the patent. Factors such as differences in tissue handling and cell-to-cell interactions could affect the outcome, meaning the patented result was not inevitable from the prior art methods.
Because Restem did not effectively challenge all of the PTAB’s reasons for upholding the patent, the Federal Circuit affirmed the decision. This case highlights the importance of careful claim construction, the limitations of arguing invalidity based on inherency, and the overall need for clear evidence when arguing that a patent is invalid due to prior art.