Patenting stem cell treatments in the U.S. presents a complex challenge, particularly when a product is defined solely by natural surface markers without genetic modifications. Such inventions often fail to meet patentability criteria due to their status as “products of nature.”
A popular strategy for overcoming this hurdle is the use of product-by-process claims, where a product is defined by the method of its manufacture.
The recent decision by the U.S. Court of Appeals for the Federal Circuit in Restem v. Jadi Cell confirmed that such claims are considered novel if the product itself is new, regardless of whether the process steps were described in the prior art.
The dispute centered on patent US9803176 for JadiCell’s umbilical cord-derived mesenchymal stem cells, which were used to treat acute respiratory distress syndrome in COVID-19 patients. Restem LLC, which develops its own umbilical cord cell platforms for treating autoimmune and orthopedic diseases, challenged the patent before the Patent Trial and Appeal Board (PTAB), arguing that the prior art already anticipated the creation of similar cells.
A key aspect of the case was the interpretation of the term “isolated cell.” In U.S. patent law, this term is used to distinguish a cell therapy product from cells existing naturally in the human body, emphasizing that they have been removed from their natural environment and exist in a controlled state. Restem argued that, according to the patent specification, the term referred to a single cell; however, the Federal Circuit, after analyzing the prosecution history, concluded it referred to a population of cells. The court noted that the examiner repeatedly mentioned “population,” and that measuring the specific markers listed in the claim is technically only possible for a group of cells.
Furthermore, the court addressed the issue of “inherent anticipation.” Restem insisted that following the process described in the prior art would automatically result in the claimed product. However, the Federal Circuit emphasized that when evaluating the patentability of such claims, the focus must remain on the product itself, as “an old product is not rendered patentable merely because it is produced by a new process.” The court was satisfied that the methods in the prior art would lead to different intercellular interactions and marker profiles than those obtained from the subepithelial layer of the umbilical cord according to the JadiCell patent.
While this decision is positive for the regenerative medicine industry, the enforcement of such patents remains problematic. When establishing infringement of a product-by-process claim, the focus shifts to the manufacturing steps: the infringer’s product must not only be identical in properties but must also be manufactured specifically using the patented technology.
Interestingly, in Europe, the patent holder was able to obtain a product-per-se patent, whereas in the U.S., they were limited to a product-by-process claim due to stricter subject-matter eligibility requirements following the Myriad case. Consequently, applicants in the U.S. are forced to balance the ease of obtaining a patent by adding process descriptions against the difficulty of subsequent litigation, or otherwise seek alternative pathways.
Founder of Research & Patent group Intectica, author of patent algorithms for solving problems in the pharmaceutical industry, patent attorney certified in all intellectual property objects (Patents, Design, TM), with education in chemistry and law, chief expert of the patent institution of Ukraine UKRPATENT (1997-2004). Member of international organizations, including ECTA, PTMG, UAM, lecturer and blogger.
