Illumina Cambridge Ltd v Latvia MGI Tech SIA & Ors

For obviousness, the skilled person may differ from the addressee of the patent. The court should identify the problem, locate it within the established field existing at the priority date, and construct the notional person or team working in that field.

Enablement across a claim is required throughout any range relevant to the invention’s value or utility. Ordinary structural or functional language may cover later-developed embodiments without causing insufficiency, provided the skilled person can select suitable embodiments without undue burden.

A combination is not a mere collocation where its components are capable of materially interacting and their satisfactory non-interference must be established experimentally. Under the doctrine of equivalents, an express and deliberately narrow definition may show that strict compliance was intended, even where the excluded variant is immaterial.

The claimant owned five patents concerning DNA sequencing by synthesis. Three modified-nucleotide patents claimed the use of a 3′-O-azidomethyl group as a reversible chain terminator. A fourth patent claimed the use of ascorbate in an imaging buffer to mitigate photodamage. The fifth concerned a fluorescent dye-linker-nucleotide conjugate.

The defendants proposed to market StandardMPS, CoolMPS, a two-colour variant and DNBSEQ E. They denied infringement of disputed claims and challenged validity for obviousness, insufficiency, lack of technical contribution and added matter. The court also considered priority, amendments, claim construction, infringement by equivalents and whether the dye conjugate was a mere collocation.

1. Modified-nucleotide patents. EP (UK) 1 530 578, EP (UK) 3 002 289 and EP (UK) 3 587 433 were valid in their amended forms. For obviousness, the relevant skilled team worked in the established field of sequencing by synthesis. Although reversible chain termination and its lack of practical success formed part of the common general knowledge, the team had no reason to read Zavgorodny’s synthetic-chemistry disclosure as proposing azidomethyl for sequencing. Nor was there a reasonable prospect that the modified nucleotide would be incorporated and deblocked with useful speed and yield. The claims were therefore inventive.

2. The priority document gave an enabling and plausible disclosure that 3′-O-azidomethyl nucleotides could be incorporated, block efficiently and be removed under neutral aqueous conditions. The relevant claims were entitled to priority. The insufficiency challenges also failed. The choices of nucleotide, polymerase, linker and label were not ranges relevant in the Regeneron sense, and suitable components could be selected without undue burden. Read length was not a claimed relevant range.

3. The unamended synthesis limb of the method claims served no useful purpose and lacked technical contribution. Deleting that limb was allowed. The remaining amendments did not add matter, subject to the claimant explaining the purpose of the amendment to claim 9 of the 289 patent.

4. All four accused systems infringed the specified claims of the 578 and 433 patents and claims 1, 5 and 6 of the 289 patent. CoolMPS infringed the 578 method claim because incorporation could occur in two stages and a non-covalent antibody structure could constitute a cleavable linker. The two-colour and DNBSEQ E systems infringed the 578 kit claim, but not claim 4 of the 289 patent, which required labelled nucleotides of all four types.

5. Ascorbate patent. EP (UK) 1 828 412 was invalid. In light of Buechler and the common general knowledge, it was obvious to add ascorbate to mitigate the appreciable risk of fluorescence-induced DNA photodamage. CoolMPS was outside the claim both literally and by equivalence because the specification deliberately defined incorporation by formation of the phosphodiester linkage.

6. Dye-conjugate patent. EP (UK) 2 021 415 was valid and infringed by StandardMPS. Its molecule was a single invention, not a collocation. The dye and linker-nucleotide portions could interact, and satisfactory non-interference required experimental demonstration.

not stated in the judgment.