Factual and Procedural Background
These proceedings originated as patent revocation actions brought by Company A and Company B against Company C, seeking to revoke two European Patents (UK) Nos. 722730 and 1258246 held by Company C, and for declarations of non-infringement regarding pharmaceutical products intended for marketing in the United Kingdom. Company C counterclaimed for patent infringement, asserting the patents' validity and infringement by Company A and Company B. Consequently, the declaratory relief claims became unnecessary and the case proceeded as a conventional patent infringement action. The patents concern controlled release formulations of the opioid analgesic oxycodone, focusing on formulations achieving slow release with a priority date in 1991. The defendants denied infringement primarily on claim construction grounds and challenged validity on added matter and obviousness, including attacks based on common general knowledge and two specific prior art citations.
Legal Issues Presented
- Whether the patents in suit (Nos. 722730 and 1258246) are valid, particularly in relation to added matter and obviousness.
- Whether the accused product infringes the claims of the patents, with emphasis on claim construction concerning the location of oxycodone relative to the film coating and the presence of a spheronising agent.
- The proper construction of key claim terms such as "matrix," "spheroids," and "spheronising agent."
- Whether the prior art documents Oshlack and Goldie render the patents obvious.
Arguments of the Parties
Company A and Company B's Arguments
- The claims require all oxycodone salt in the formulation to be contained within the film coating; presence of oxycodone outside the coating negates infringement.
- The term "spheronising agent" refers narrowly to materials enabling the extrusion/spheronisation process, excluding binders or materials added after spheroid formation.
- The patents include an impermissible disclaimer excluding acrylic resin matrices providing pH-independent dissolution, which constitutes added matter contrary to EPO case law.
- The patents lack inventive step, being obvious over common general knowledge and the prior art documents Oshlack and Goldie.
- Obviousness is founded on the premise that oxycodone was a known alternative to morphine and that controlled release formulations of known drugs are straightforward to develop.
- Testing for infringement under the USP Paddle Method must involve batch acceptance procedures, not just single dosage form testing.
Company C's Arguments
- The claims do not require all oxycodone to be within the film coating; presence of an immediate release layer outside the coating is consistent with the claim language and common general knowledge.
- The term "spheronising agent" includes any material assisting in spheroid formation, not limited to extrusion/spheronisation.
- The disclaimer in the patent does not add matter relevant to the invention and does not confer any unwarranted advantage.
- Oxycodone was generally regarded as a weak opioid co-formulated with other drugs and not as an alternative to morphine; thus, the skilled person would not have been motivated to develop a controlled release oxycodone formulation.
- The prior art documents do not disclose or motivate the claimed 12-hour controlled release formulations with the claimed pharmacokinetic profiles.
- Single dosage form testing under the USP Paddle Method is appropriate for assessing infringement.
Table of Precedents Cited
| Precedent |
Rule or Principle Cited For |
Application by the Court |
| Corus UK Ltd v Qualchem [2008] EWCA Civ 1177 |
Requirement of a "killer" blow in patent invalidity attacks |
Referenced to highlight the finely balanced nature of the case and the lack of a decisive invalidity argument. |
| Kirin Amgen v TKT [2005] RPC 9 |
Principles of purposive construction of patent claims |
Guided the court's approach to claim construction, emphasizing the skilled person's understanding of claim language. |
| European Central Bank v. Document Security Systems [2007] EWHC 600 (approved on appeal [2008] EWCA Civ 192) |
Test for added matter under Art 123(2) EPC |
Applied to assess whether amendments or disclaimers added subject matter beyond the original disclosure. |
| Bonzel v. Intervention Ltd [1991] R.P.C. 553 |
Framework for assessing added matter |
Provided the threefold test for added matter applied by the court. |
| PPG Industries Case G1/03 (EPO Enlarged Board of Appeal) |
Permissibility and criteria for undisclosed disclaimers |
Considered in relation to the patent disclaimer excluding pH-independent acrylic resin matrices. |
| Pozzoli v BDMO SA [2007] EWCA Civ 588 |
Structured approach to obviousness (Windsurfing questions restated) |
Used to structure the court’s analysis of inventive step. |
| Conor v Angiotech [2007] UKHL 49 |
Factors relevant to assessing obviousness |
Informed the court's weighing of motivation, research effort, and expectation of success. |
| Generics (UK) Ltd v H Lundbeck A/S [2007] RPC 32 |
Considerations in obviousness analysis |
Approved by the House of Lords and applied in assessing the factual matrix of obviousness. |
| Beloit Technologies Inc v Valmet Paper Machinery Inc [1997] RPC 489 |
Definition and scope of common general knowledge |
Applied to determine whether evidence established common general knowledge regarding oxycodone. |
| Generics (UK) v Daiichi Pharmaceutical [2008] EWHC 2413 |
Distinction between information forming part of common general knowledge and information only found after research |
Guided the court’s assessment of what constitutes common general knowledge relevant to obviousness. |
| General Tire & Rubber Co. v. Firestone Tyre & Rubber Co. Ltd. [1972] R.P.C. 457 |
Common general knowledge and widely read publications |
Referenced in the context of what constitutes common general knowledge in the art. |
Court's Reasoning and Analysis
The court undertook a detailed claim construction exercise, focusing particularly on the location of oxycodone relative to the film coating and the meaning of terms such as "matrix," "spheroids," and "spheronising agent." The court concluded that claims requiring a film coating controlling release necessitate that all oxycodone be within that coating, rejecting the argument that an immediate release layer outside the coating could be consistent with infringement for certain claims (notably claim 1 of 246). However, for claim 6 of patent 730, the court found no requirement that all oxycodone be within spheroids.
On added matter, the court analyzed the disclaimer excluding acrylic resin matrices providing pH-independent release. It held that this disclaimer did not add matter relevant to the invention or confer any unwarranted advantage, distinguishing it from impermissible undisclosed disclaimers under EPO case law. The court also rejected the alternative added matter attacks concerning intermediate generalization and technical contribution.
Regarding obviousness, the court carefully examined the common general knowledge about oxycodone at the priority date. It found that oxycodone was widely regarded as a weak opioid co-formulated with other analgesics, not as a substitute for morphine in moderate to severe pain treatment. The skilled team would not have been motivated to develop a controlled release oxycodone formulation as an alternative to morphine, diminishing the force of obviousness attacks based on common general knowledge.
Turning to the prior art, Oshlack disclosed controlled release matrices including oxycodone but only enabled a rapid release formulation unsuitable for 12-hour dosing. The court found that a skilled formulator could attempt to develop a longer release formulation but that Oshlack did not provide sufficient motivation or teaching to reach the claimed invention without inventive effort.
The Goldie patent concerned hydromorphone, not oxycodone. The court held that, absent a perception of oxycodone as a morphine-equivalent, Goldie would not prompt the skilled person to develop a controlled release oxycodone formulation.
The court emphasized the importance of avoiding hindsight and noted that the skilled team would include clinicians, formulators, and pharmacologists, but that clinical experience with oxycodone as a morphine alternative was lacking at the priority date.
On infringement, the accused product contained oxycodone outside the polymer-controlled release layer and lacked a spheronising agent as claimed. The court found no infringement of the asserted claims of either patent.
The court allowed the unopposed amendments to the patents and concluded that neither patent was invalid for added matter or obviousness.
Holding and Implications
The court held that neither patent 722730 nor patent 1258246 was infringed by the accused product, and that both patents were valid, not invalid for added matter or obviousness.
The direct consequence is dismissal of the infringement claims against Company A and Company B. The court did not establish any new precedent beyond applying established principles of patent law. The decision underscores the importance of the skilled person's perception of the relevant drug in assessing obviousness and claim construction in patent infringement disputes.