BASF AG v Smithkline Beecham Plc

Patent claims are construed from their words, read with the specification and drawings, using the middle ground required by the Protocol on Article 69: fair protection for the patentee and reasonable certainty for third parties. Ambiguity is not presumptively resolved in favour of validity. Ordinary words cannot be replaced with a broader expression merely to reflect the alleged technical contribution. For anticipation, a prior publication must provide an enabling disclosure and clear, unmistakable directions to the claimed invention. A merely possible or non-inevitable result is insufficient. Obviousness is assessed by the four-stage Windsurfing inquiry. On appeal, caution is required before disturbing a trial judge’s evaluation of obviousness where the issue is one of degree.

SmithKline Beecham Plc appealed against Pumfrey J’s judgment of 12 July 2002, reported as [2002] EWCH 1373 (CH). The judge held claims 1, 2, 3, 7, 10(ii), 12 and 13 of the patent invalid, but held claims 10(i) and 11 valid.

SmithKline Beecham challenged the construction of the phrase “substantially free of bound propan-2-ol” in claim 3. BASF AG cross-appealed on the validity of claims 10(i) and 11, alleging anticipation and obviousness based on UK patent application 8526407. The central issues were the proper construction of the claims, whether the prior disclosure inevitably disclosed the claimed process, and whether that process was obvious.

Disposition. The Court of Appeal unanimously dismissed both the appeal and the cross-appeal. Claims 10(i) and 11 therefore remained valid.

1. Construction. Under section 125 of the Patents Act 1977 and the Protocol on the Interpretation of Article 69, claims must be construed between strict literalism and treating claims as mere guidelines. The balance is between fair protection and reasonable certainty. The court rejected any general rule that ambiguity should be resolved in favour of the patentee. The technical contribution may inform construction, but cannot justify changing the ordinary meaning of “propan-2-ol” to “organic solvent” where the specification permits a coherent construction in ordinary language.
2. The definition in the specification used the amount of propan-2-ol remaining after conventional vacuum drying as the benchmark for being substantially free of bound solvent. This supported the judge’s construction of claim 3. The claim was therefore anticipated, and the appeal was dismissed.
3. Novelty. A prior publication must contain clear and unmistakable directions to do what the claim covers. An inevitable result may anticipate, but a direction capable of being performed in an infringing or non-infringing manner does not. The disclosure must also enable the public to implement the invention. The court declined to assume that the test for sufficiency under section 72(1)(c) of the Patents Act 1977 necessarily governs anticipation.
4. Example 1 of application 8526407 did not anticipate claim 11. Its use of concentrated hydrochloric acid introduced water, the instruction to add more isopropanol did not specify the substantial quantities used by BASF, and the prior document gave no direction for the careful filtering and drying conditions relied upon. Those changes went beyond ordinary replication and further information was required.
5. Obviousness. Applying the four-stage Windsurfing approach, the inventive concept was the production of pure paroxetine hydrochloride anhydrate by forming a solvate and displacing the solvated solvent. The judge was entitled to find that the skilled team would not retain the anomalous water-washing step while seeking anhydrous conditions. In light of the appellate caution required in reviewing an evaluation of obviousness, the cross-appeal was dismissed.

• Court of Appeal (Civil Division): On 25 June 2003, dismissed SmithKline Beecham Plc’s appeal and BASF AG’s cross-appeal.
• Chancery Division: Pumfrey J’s judgment of 12 July 2002, [2002] EWCH 1373 (CH), held claims 1, 2, 3, 7, 10(ii), 12 and 13 invalid, and claims 10(i) and 11 valid.