Dr Reddy’s Laboratories (UK) Limited v Boehringer Ingelheim International GmbH

Parties must plead the material facts, but need not plead the law. A party may therefore advance a legal argument without specifically pleading it, provided the facts are pleaded.

Where proposed evidence may become relevant only if the law changes and the court cannot yet assess its relevance or any unfairness, it may let the evidence proceed to trial while reserving its admissibility.

Dr Reddy’s Laboratories (UK) Limited brought patent proceedings against Boehringer Ingelheim International GmbH and related parties. Dr Reddy’s advanced an ab initio implausibility argument. At a pre-trial review, Boehringer sought to rely on experimental results for a wider group of compounds through a September CEA Notice. The issue was whether that material should be excluded or taken forward to trial, although its relevance depended on a possible change in the law and questions about the scope and fairness of the evidence remained unresolved.

The judge provisionally directed that the materials in the September CEA Notice proceed to trial. He reserved a final ruling on their admissibility.

1. Pleading. The law need not be pleaded, but the facts must be. Dr Reddy’s could therefore run its ab initio implausibility argument without specifically pleading the legal argument, provided the relevant facts were pleaded ([2]).
2. Scope of the proposed evidence. Boehringer had flagged possible reliance on pre-existing evidence concerning empagliflozin, but its September Notice sought to extend the evidence to a wider group of compounds. The judge accepted that he should be slow to exclude it and saw no real reason to think Dr Reddy’s could contradict the results. At the pre-trial review, however, he could not confidently assess whether the material gave an incomplete picture or whether other tests or compounds might change that assessment ([3]–[5]).
3. Conditional relevance and next steps. The evidence could matter to the merits only if the Supreme Court changed the law and other factual matters aligned. The judge considered that possibility could not be ruled out, referring to legal uncertainty and other courts’ treatment of actual results in different litigation contexts. He did not decide the governing law or finally admit the evidence ([6]).
4. The parties were to prepare to address the September Notice at trial. The judge would decide admissibility then, including whether admitting only that material without a wider inquiry would be unfair. The parties could make further submissions after considering the hearing. Although the judge suspected the evidence would not matter, he considered it preferable to have it available in case it did ([7]–[8]).