Understanding "teaching away" in Obviousness Rejections

In the recent non-precedential decision Laboratory Corporation of America Holdings v. Ravgen, Inc. (No. 2023-1342, Fed. Cir., Jan. 6, 2025), the Federal Circuit affirmed the Patent Trial and Appeal Board's ("Board") decision upholding the patentability of claims in U.S. Patent No. 7,332,277 (the '277 patent). The case provides valuable insights into how courts evaluate "teaching away" arguments and the motivation-to-combine analysis in overcoming obviousness rejections under 35 U.S.C. § 103.

Background of the Case

The '277 patent, owned by Ravgen, Inc., covers non-invasive methods for analyzing cell-free fetal DNA (cffDNA) to detect genetic disorders. Laboratory Corporation of America Holdings (Labcorp) challenged the patent's validity in two inter partes reviews (IPRs), arguing that the claims were obvious based on prior art references: the 2001 Chiu article on blood-processing protocols and two patents disclosing the use of formaldehyde compounds for stabilizing DNA.

The Board upheld the claims, finding that Labcorp failed to demonstrate a motivation to combine the references. Labcorp appealed, asserting legal and factual errors in the Board's analysis.

Key Arguments and the Teaching Away Doctrine

Labcorp's primary argument on appeal was that the Board imposed an improperly high standard for obviousness by focusing on the potential drawbacks of combining the references. Specifically, the Board determined that a skilled artisan would have been dissuaded from using formaldehyde compounds disclosed in the prior art because of their potential to damage cffDNA or cause maternal DNA leakage.

Labcorp argued that the Board's analysis misapplied the motivation-to-combine standard by demanding perfection in the proposed combination rather than considering whether it was merely desirable. Citing precedents such as In re Fulton and Medichem v. Rolabo, Labcorp contended that the simultaneous advantages and disadvantages of a combination do not negate a motivation to combine.

The Federal Circuit disagreed, emphasizing that the Board's findings were grounded in the specific disclosures of the prior art and the claimed invention. The Board relied on expert testimony indicating that formaldehyde compounds were known to create issues—such as DNA leakage or damage—that would conflict with the goals of the Chiu method for analyzing cffDNA.

Specifically, the Federal Circuit found that the Board correctly found that Labcorp failed to "provide persuasive argument or evidence to explain why creating holes in the cell membrane…would have been by the [person of ordinary skill in the art] as acceptable." The Board also relied on concerns specific to the combination of references rather than on general "industry skepticism" concerning the potential of DNA damage. Moreover, the Board considered adequately whether a person of ordinary skill, a high level of skill in this context, would have pursued the invention despite the concerns of DNA damage.

While this evidence did not constitute "teaching away" in the strictest sense, it provided substantial evidence that a skilled artisan would be discouraged from pursuing the cited combination.

What Constitutes Teaching Away?

The court clarified that while teaching away requires a prior art reference to "criticize, discredit, or otherwise discourage" a proposed combination, evidence of practical challenges or concerns specific to the claimed invention can weigh against a motivation to combine. Here, the Board relied on:

• The potential for formaldehyde compounds to damage DNA, as noted in the references.

• Expert testimony that even minor DNA leakage or damage would undermine the utility of the Chiu method for detecting cffDNA.

This nuanced approach aligns with precedents like Arctic Cat v. Bombardier, which recognized that even absent explicit teaching away, evidence discouraging a combination is relevant to the obviousness analysis.

Overcoming Obviousness Rejections: Practical Takeaways

Focus on Context-Specific Concerns: Arguments for or against a motivation to combine should address concerns unique to the claimed invention. Generic skepticism or advantages are less persuasive.

1.      Leverage Teaching Away Strategically: While formal teaching away remains a high bar, evidence showing that prior art would discourage a skilled artisan can be equally compelling.

2.      Substantiate Practical Challenges: Expert testimony and experimental evidence demonstrating the drawbacks of a proposed combination carry significant weight.

Conclusion

The Federal Circuit's decision in Labcorp v. Ravgen underscores the importance of detailed and context-specific analysis in obviousness disputes. Teaching away is not the only path to rebutting a motivation to combine—practical concerns and technical challenges can be equally effective. Patent practitioners should carefully evaluate the interplay between prior art disclosures and the claimed invention when formulating arguments for patentability.