## Facts

- Eli Lilly owned a European patent (UK and other designations) claiming the use of pemetrexed disodium with vitamin B12 (and optionally folic acid) in treating cancer, based on reducing serious side effects.
- The key claim referred expressly to “pemetrexed disodium” in the manufacture of a medicament for use with vitamin B12 (and optionally folic acid).
- Actavis planned to market generic products containing pemetrexed in non-disodium forms: pemetrexed diacid, pemetrexed ditromethamine, and pemetrexed dipotassium.
- The proposed products would be dissolved for intravenous infusion, yielding pemetrexed anions in solution and introducing sodium ions via saline and related preparation steps.
- Lilly alleged the proposed products would infringe the patent directly or indirectly in the UK and in parallel designations in France, Italy, and Spain.
- The trial court found no direct or indirect infringement; the intermediate appellate court found indirect but not direct infringement; both sides appealed.

## Issues

1. Whether products using pemetrexed salts other than pemetrexed disodium directly infringed the claim when construed under Article 69 EPC and its Protocol, including protection for equivalents.
2. Whether supplying those products for preparation and administration with vitamin B12 constituted indirect infringement under the relevant statutory provisions (including the UK Patents Act 1977 s 60(2)).
3. Whether, and in what circumstances, the patent prosecution history may be used to limit claim scope or defeat infringement by equivalents.

## Decision

- The Supreme Court held Actavis’s proposed products directly infringed across the relevant designations, not on the ordinary meaning of the words, but by infringement by equivalents.
- On ordinary interpretation, “pemetrexed disodium” did not cover other pemetrexed salts; the products fell outside the claim’s literal scope.
- Applying a distinct equivalents analysis, the Court found the alternative salts achieved substantially the same result in substantially the same way once prepared and administered with vitamin B12; the sodium counter-ion was not essential to the invention.
- The Court also upheld the finding of indirect infringement for the UK designation because Actavis would supply means relating to an essential element of the invention for putting it into effect, with foreseeable use meeting the claim conditions.
- The Court rejected reliance on the prosecution history to narrow the claim, holding that resort to the file is generally improper except in limited, exceptional situations.

## Legal Principles

- Patent infringement in this context should be addressed in two stages: (1) whether the variant falls within the claim on normal interpretation; and (2) if not, whether it nonetheless infringes because the differences are immaterial (equivalents).
- The Protocol to Article 69 EPC requires protection beyond strict literalism where a variant is an equivalent; “purposive construction” does not exhaust the inquiry.
- The “Protocol/Improver questions” function as non-mandatory guidelines for assessing immaterial variation, including whether the variant achieves substantially the same result in substantially the same way, and whether the skilled person would treat the literal term as essential even knowing the variant works.
- Indirect infringement may arise where a party supplies means relating to an essential element of the invention for putting it into effect, and the intended or foreseeable use implements the claimed combination.
- Prosecution history should generally not be consulted in construing claims or limiting equivalents; it may be considered only where it clearly and objectively resolves genuine ambiguity, not where it reflects negotiation positions or compromises.

## Conclusion

The Supreme Court broadened UK infringement analysis by separating claim interpretation from an equivalents inquiry, held alternative pemetrexed salts infringed as immaterial variants, confirmed indirect infringement on foreseeable supply-and-use facts, and confined prosecution-history reliance to rare cases.


Actavis UK Ltd. v. Eli Lilly & Co., [2017] UKSC 48 (UK) (2017)