## Facts

- Sequenom and related entities asserted U.S. Patent No. 6,258,540, claiming methods for prenatal diagnosis using cell-free fetal DNA (cffDNA) found in maternal plasma or serum.
- The discovery underlying the patent was that fetal DNA exists in maternal blood components previously discarded, enabling noninvasive prenatal testing.
- Representative claims required taking a maternal plasma/serum sample, amplifying paternally inherited fetal nucleic acid (e.g., by PCR), and detecting it.
- Ariosa and others filed a declaratory-judgment action in the Northern District of California challenging the patent’s validity.
- The district court granted summary judgment that the asserted claims were invalid under 35 U.S.C. § 101.
- Sequenom appealed to the Federal Circuit.

## Issues

1. Whether the asserted method claims are directed to a patent-ineligible natural phenomenon under 35 U.S.C. § 101.
2. If so, whether the additional claim steps (amplifying and detecting cffDNA using known techniques) add an “inventive concept” sufficient to make the claims patent-eligible under the Mayo framework.

## Decision

- The Federal Circuit affirmed summary judgment of invalidity under § 101.
- The court held the claims were directed to a natural phenomenon: the presence of paternally inherited cffDNA in maternal plasma or serum.
- The court held the remaining steps—sample preparation, amplification, and detection—were well-understood, routine, and conventional in the art and therefore did not supply the required inventive concept.
- The court rejected arguments that the invention’s medical importance, practical utility, or commercial success could alter the § 101 analysis.
- A concurrence agreed the result was compelled by Supreme Court precedent, while expressing concern that the framework barred valuable diagnostic inventions.

## Legal Principles

- Under Mayo step one, claims focused on a naturally occurring correlation or substance are directed to a patent-ineligible natural phenomenon even if the discovery was previously unknown.
- Under Mayo step two, appending routine and conventional laboratory steps (including known amplification and detection techniques) to a natural phenomenon does not transform the claim into patent-eligible subject matter.
- Evidence that an invention is beneficial, noninvasive, or widely used does not substitute for an inventive concept in the claim limitations.
- Preemption concerns are addressed through the Mayo/Alice analysis and do not operate as a separate, free-standing test once a claim is directed to a natural phenomenon without an inventive concept.

## Conclusion

The Federal Circuit held that method claims for detecting naturally occurring cffDNA in maternal blood, implemented through conventional amplification and detection steps, are not patent-eligible under § 101 because they claim a natural phenomenon without additional inventive subject matter.


Ariosa Diagnostics, Inc. v. Sequenom, Inc., 788 F.3d 1371 (Fed. Cir. 2015)