As I write this there’s a voice in my head saying, “Be careful what you wish for!” but it has been five months since Sequenom was argued at the Federal Circuit, and the court has yet to issue its decision. (You can read my summary of the oral arguments here.) In the meantime, neither the USPTO nor stakeholders know whether or when diagnostic methods and personalized medicine methods can be patented.

The USPTO’s Interim Guidance on subject matter eligibility draws from Mayo v. Prometheus, but does not provide many specific touchstones for eligibility. (The USPTO’s the Nature-Based Products Examples do not include any diagnostic method claims.) While many of the public comments address the eligibility of diagnostic methods, the USPTO does not know how to respond with Sequenom still undecided.

At the examination level, while some examiners are willing to allow diagnostic methods when the marker itself is novel or when the method otherwise recites an unconventional technique, most diagnostic method applications are in a holding pattern. Applicants are advised to file Requests for Continued Examination or pursue appeals to keep their applications pending until the Federal Circuit sheds more light on this legal issue.

I am leery of how the court will decide this case, but the uncertainty is making it difficult to counsel clients on the patentability of diagnostic inventions, and the soundness of investing in such essential technologies without the promise of patent protection.