Illumina, Inc & Anor v TDL Genetics Ltd & Ors

A product-by-process patent claim may be construed so that its process features limit infringement, obviousness and sufficiency. A claim directed to enrichment by size separation does not necessarily require a specified degree of enrichment. Sufficiency depends on whether the disclosure makes the technical contribution claimed available without undue burden across the scope of protection. A general technical principle may justify a claim in general terms, even though its practical benefit varies between cases.

The claimants alleged that the Harmony non-invasive prenatal test infringed a patent concerning size separation of extracellular fetal DNA in maternal plasma or serum. The defendants counterclaimed for revocation on grounds of obviousness over the Ikeda conference abstract, insufficiency and discovery as such.

The principal issues were claim construction, the skilled person’s interpretation of Ikeda without hindsight, sufficiency, patentability as against the discovery exclusion, and infringement.

1. Construction. Claim 1 was a product-by-process claim. Its process features limited the scope of the claim for infringement, obviousness and sufficiency. “Extracellular DNA” was not confined to DNA already extracellular in circulation. The claim did not require at least 2.0-fold enrichment. A size separation required something capable of being separated; the claim therefore did not cover a fraction from a sample containing no extracellular DNA above 500 base pairs.
2. Ikeda and obviousness. Ikeda was a short, unreviewed conference abstract and had to be read with caution and without hindsight. Properly understood, it suggested that shorter fetal DNA fragments might be more prevalent than longer fetal DNA fragments. It did not disclose a size difference between fetal and maternal DNA. On that construction, the claims were not obvious. The alternative interpretation advanced by the defendants was not a proper basis for obviousness.
3. Insufficiency. The court applied the principles reviewed in Regeneron Pharmaceuticals Inc v Kymab Ltd [2018] EWCA Civ 671. The claims disclosed a general principle of technical utility: fetal cell-free DNA in maternal plasma or serum could be enriched by size separation at 500 base pairs. Variation in the extent of enrichment did not make the claims insufficient. Their breadth was commensurate with the technical contribution.
4. Translation evidence. Translation was expert evidence. Where disputed, permission was required and the translators had to be appropriately qualified. The word mata in Ikeda was best translated as “in addition”.
5. Disposition. The Harmony Test included the claimed size-separation step and infringed at least claim 1. The claims were not obvious and were not insufficient. The court declined to make proposed factual findings concerning discovery as such because they were sought in a legal vacuum.