Illumina, Inc v Premaitha Health Plc

A patent claiming a principle of general application may extend to later inventive improvements or technological developments which use that principle, without being insufficient solely because those developments were not enabled at the priority date. Sufficiency remains fact-sensitive: the disclosure must enable the invention across the scope claimed, subject to the nature of the technical contribution.

For obviousness, the skilled person must read the prior art as a whole and must have a fair prospect of success. A technically straightforward experiment is not necessarily obvious where the prior art is scientifically implausible or unreliable. Patent claims are given a purposive construction. A method of detecting foetal DNA may include indirect detection where that construction is consistent with the patent’s technical contribution.

These proceedings concerned five patents relating to non-invasive prenatal diagnosis using maternal blood samples. The claimants alleged that tests developed by Premaitha Health Plc and other defendants infringed patents concerning detection of foetal DNA, digital analysis and random genomic sequencing. The defendants challenged validity on grounds including obviousness, lack of priority, insufficiency, added matter and excluded subject matter. They also disputed infringement and the claimants’ entitlement to sue as exclusive licensees.

The principal issues included whether the Lo 1 patent was obvious over Kazakov; whether the Quake and Lo 2/3 patents were obvious over Shimkets; whether the patents enabled the claimed methods; and whether the IONA and Harmony tests fell within the claims.

1. Lo 1 and Kazakov. Lo 1 was not obvious over Kazakov. The skilled person would read the paper as a whole. Its conclusions were unsupported by reliable data, and its theory concerning inter-Alu repeats and foetal DNA was implausible. The skilled team would not have had a fair prospect of success from pursuing it.
2. Priority and sufficiency. The Lo 1 Priority Document disclosed, directly and unambiguously, a general principle that detectable paternally inherited cell-free foetal DNA could be used for prenatal diagnosis. The later Harmony polymorphic assay was an inventive technological improvement which could fall within the claim without depriving the patent of priority or sufficiency. Claims 1, 2, 5 and 7 nevertheless lacked priority and were insufficient because the disclosure of applications for aneuploidy and pre-eclampsia was implausible across their scope. Claim 8, limited to sex determination, was entitled to priority.
3. Excluded subject matter and construction. Claim 1 was, if necessary to decide, a practical detection process and not a discovery as such. The claims were purposively construed. “Detection” was not limited to direct observation of the relevant sequence. The IONA test indirectly detected the paternally inherited Y chromosome by identifying the relevant level of X-chromosome sequences.
4. Quake and Lo 2/3 patents. The Quake and Lo 2/3 patents were not obvious over Shimkets. Shimkets concerned isolated foetal cells and separately acquired reference information, whereas the patents used mixed maternal and foetal material without isolating or identifying foetal DNA. Quake 1 was insufficient and contained added matter as granted in relation to digital PCR, but the proposed amendments cured those defects. Lo 2 and Lo 3 were entitled to priority.
5. Infringement and title. The IONA test infringed the valid claims of the Quake and Lo 2/3 patents and infringed claim 8 of Lo 1 when used for sex determination. The Harmony non-polymorphic assay infringed claim 8 of Lo 1 for sex determination; the polymorphic assay would have infringed claim 1 had that claim been valid. Illumina was not an exclusive licensee of Lo 1, but Verinata and Illumina were exclusive licensees of the Quake and Lo 2/3 patents for the relevant commercial fields. A process substantially performed in the United Kingdom was not avoided by sending automated data-processing steps abroad.