In my experience, since the PTAB—again, that’s the Patent Trial and Appeal Board—is more concerned about the facts and science of the issues specifically before them in each IPR more so than simply applying past precedent, I think it’s very hard to generalize across an entire subset of patents based on just one patent and what happened to it in the IPR.
It’s true that it appears that method claims haven’t fared as well as formulation claims in IPRs. But it’s important to note that this might just be a function of the patents that have been challenged so far. Method of treatment patents tend to be filed later in time, so petitioners may also be looking at them more often because they have later expiration dates in patent portfolios. And if you have more of a certain type of patent being challenged, of course you’re going to have a higher likelihood of seeing them invalidated, so it may be a product of what we’re seeing challenged.