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Held to Their Word: Patents Ruled Unpatentable that were Described as “Conventional”

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A recent decision by Judge Colm Connolly of the United States District Court for the District of Delaware, in CareDx, Inc. et al. v. Natera, Inc., 1-19-cv-00567, serves as a reminder of the need to consider every pillar of patentability when drafting a specification. Additional words can often be helpful to avoid a variety of rejections, but examiners and judges alike may sometimes find that words or phrases used to describe elements of patent claims in fact serve as proof of a patent’s unpatentability. While the importance of caution in written statements is a common theme in all legal fields, the consequences are particularly acute in patent prosecution because the rules of claim construction require whoever interprets claims to first look at intrinsic evidence to determine their meaning.

The question at issue in the aforementioned decision was whether three of CareDX’s patents were invalid under §101 as having claims directed to a natural phenomenon. See CareDx, Inc. et al. v. Natera, Inc., 1-19-cv-00567 (DDE 2021-09-28 Order) (Colm F. Connolly) at 23-24. Judge Connolly found that they were, despite conflicting expert testimony, largely because the specification described the steps as “conventional.” Id. at  24. Judge Connolly noted that the method claims in each of these patents could be broken down into steps before stating that “[t]the patents’ written description expressly states that the techniques referred to in these steps are, ‘unless otherwise indicated, conventional techniques of immunology, biochemistry, chemistry, molecular biology, microbiology, cell biology, genomics, and recombinant DNA, which are within the skill of the art.’” Id. at 8-9 (emphasis added).

This decision came after an interesting procedural history involving a denial of a motion to dismiss and a stay of all proceedings not directly related to the question of patent validity under §101 which resulted in an order against summary judgement. Id. at 11-16.  Judge Connolly then, sua sponte, decided to rehear the issue of summary judgment after defendants raised, in their motion for certification of an interlocutory appeal, Federal Circuit case law that appeared to decide the issue of whether articles and expert testimony could raise a genuine issue of material fact where a clear statement in the specification labeled techniques conventional; this hearing resulted in the present order. Id. at 16-18. The judge faced a tension between not throwing out a case based on a legal doctrine that is widely known for its inconsistency, as well as conflicting expert testimony, and not wasting judicial resources when a gatekeeping issue could end the case before either side engaged in expensive discovery. See Id. at 12-14. Judicial efficiency won, the decision resting on a seemingly innocuous statement that had been made in each of the challenged patents. See Id. at 8-9.

After analyzing §101 as it relates to natural phenomena and methods claims, Judge Connolly concluded that there must be something unconventional about the steps themselves or in how they are combined. See Id. at 19-22. Judge Connolly pointed out that “the asserted patents do not claim an ordered combination of recited techniques” to counter the argument that the combination of techniques was nonconventional, and to help explain why the statement of nonconventionality proved so fatal to the claims. Id. at 32-33. The judge focused on whether the claimed steps were unconventional, and extrinsic evidence was similarly not enough to save the claims. See Id. at 33-34. The plaintiffs cited scientific articles and expert testimony to show that the claimed combinations were unconventional. Id. at 15-16. Judge Connolly ultimately found that, whether or not they may have been unconventional, the plaintiffs could not fairly make that argument after representing to the Patent and Trademark Office, through words in the specification, that they were not. See Id. at 26-29.

The plaintiffs objected to the use of these words as an admission of unpatentability, calling it unfair to use a common phrase that “appears in myriad patents” against them. Id. at 28. Judge Connolly responded that the unfairness would actually be against competitors who may design around the patent should they be allowed to make such a statement and not be bound to it. Id. at 28-29, 34.

Judge Connolly noted that the purpose of adding the words in the first place was to satisfy the §112 requirements of enablement and written description. Id. at 28. The words served a purpose; they aided the patent owner in being able to obtain the patents in the first place. Id. Judge Connolly compared this to when certain possible claim constructions are disclaimed through the specification or prosecution of a patent, using the principle of creating known metes and bounds for a patent to tie the two ideas together. He further asserted that the metes and bounds protect a “right to design around.” Id. at 33-34.

In a footnote, Judge Connolly compared the issue to a patent specification that specifically labels something as prior art. Id. at 26-27. He also characterized giving notice to competitors as similar to the duty of candor before the PTO. Id. at 26-28. Motivating Judge Connolly’s decision was an underlying concern with honesty and fairness when dealing with the PTO. His decision demonstrated a concern that it is unfair to represent a step in a method as conventional to convince the PTO that a person of ordinary skill would be able make the claimed invention, and later minimize the significance of the statement in order to overcome a § 101 rejection. The Court appeared to conclude that either the steps were conventional, or the patent owner misled the PTO to obtain a patent.

Significantly, in making this decision, Judge Connolly found no statements in the specification that contradicted the statement that the methods were “conventional unless otherwise noted,” and there were no places in which anything was “otherwise noted.” Id. at 9, 24. Thus, the judge’s focus on the statement did not preclude analysis of the whole specification for other intrinsic evidence that might prove unconventionality. None was found . See Id. at 24.

This case serves as one more reminder that patent drafters must consider the impact of all statements they make in patent applications. A focus on one prong of validity or eligibility, to the exclusion of others, risks adverse rulings in some courts which no amount of reliable expert testimony can save.


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