Patent Invalidity, Patent Litigation

Many, if not most, patent infringement lawsuits involve a patent owner asserting that its claims cover accused products that differ from the specifically described embodiments in the patent at issue. Patent owners typically want their claims construed broadly by the court so that they “read on” or encompass the defendant’s accused products. 

Depending on the nature of their products, defendants often ask the court to construe the patent owner’s claims narrowly so they will exclude the accused products. In addition, defendants search for the best prior art they can find to defeat the novelty and/or non-obviousness of the patent owner’s claims. 

Sometimes, the prior art is close enough to the patent owner’s claims that if the claims are construed to read on the defendant’s products, then they also encompass the prior art, rendering them invalid. Thus, the prior art can constrain how broadly the patent owner can read its claims without risking invalidation.

However, that is not always the case, and especially when it is not, it can be beneficial to assert defenses for insufficient written description and/or lack of enablement under Section 112 of the Patent Statute, because these defenses may also confine how broadly a patent owner can interpret its claims without risking invalidation. Without these defenses, if the prior art is not particularly close, the patent owner may be able to assert that its claims have a breadth that goes far beyond what they actually invented.   This is particularly important to consider if the patent owner appears to have taken a narrow specification and added broad claim language to cover the accused products, something that often happens when the patent owner prosecutes a chain of continuation applications over a number of years.  We described the written description and enablement requirements, generally, in our November 2019 Newsletter, a copy of which can be obtained here.

Under Section 112 of the Patent Statute, the Federal Circuit has held that a patent specification must “support” the full scope of what is claimed.  What does this mean? It means that the specification must indicate to persons of ordinary skill in the art (POSITAs) that the inventors were in possession of the full range of embodiments covered by the claims (written description requirement) and that the specification teaches POSITAs how to make and use the full range of embodiments covered by the claims (enablement requirement).  See LizardTech, Inc. v. Earth Resource Mapping, Inc., 424 F.3d 1336, 1346 (Fed. Cir. 2005); ICU Medical, Inc. v. Alaris Medical Systems, Inc., 558 F.3d 1368, 1378 (Fed. Cir. 2009). 

This principle seems reasonable. However, there is a competing one in tension with it: the principle that the claims cover more than the embodiments that are specifically described in the specification. There are legions of claim construction cases holding that the claims “are not limited to the preferred embodiment.” So, when does the breadth of claims relative to the specification lead to a lack of enablement and/or an insufficient written description?

In the cases finding that the written description and/or enablement requirements were not met, one key factor is whether there is some core operative principle –i.e., some method or structure that allows the invention to achieve its goals–that differs between the embodiments described in the specification and those that are not described but which are nevertheless covered by the claims. This is especially true if the specification describes a particular structure or function as being important or essential for the functioning of the invention. Ask “what is it in the specification that makes this work”? Also consider “what would the inventors have described had they actually invented these other embodiments” that were not disclosed?

Then, see if the answers to these questions reveal any distinctions between the broad range of embodiments encompassed by the claims and those that were actually described in the specification. The differences you find may provide the factual basis for a written description and/or enablement defense.   

In LizardTech only one method of making a “seamless discrete wavelet transform” or “DWT” was disclosed, yet the claims covered all methods of making them.  The significance of the disclosed method was such that the Federal Circuit held that a POSITA would not have understood the inventors to have been in possession of any others. In ICU the application only described embodiments of IV setup valves that included spikes.  Yet, the applicant sought and obtained claims that read on both “spike” and “spikeless” embodiments. The Federal Circuit held that “based on the disclosure, a [POSITA] would not have understood the inventor . . .  to have invented a spikeless medical valve,” and therefore, that claims encompassing both spikeless and spike valves were invalid under the written description requirement.  ICU Medical, 558 F.3d at 1377. 

There is another tension that defendants can use to their advantage: the tension between the written description/enablement requirements and the non-obviousness requirement.  Claims that are obvious over the prior art are invalid. When defendants assert an obviousness defense, patent owners often respond by arguing that a POSITA would have had no reason to combine or modify the prior art to obtain the claimed invention. In so doing, they often look for technical hurdles that would have prevented or at least discouraged skilled artisans from making such combinations or modifications. However, those “technical hurdles” may also establish why a POSITA would not have understood the inventors to have been “in possession of” and/or enabled the range of products falling within the scope of broad claims based on a narrow specification. If you are defending a patent case, look for these kinds of tensions early on and build a discovery plan that will enable you to develop them. Also, when these kinds of tensions exist, they often present opportunities to elicit helpful testimony from overzealous adverse experts who are not mindful of them.