Synthon BV v. Smithkline Beecham plc

Factual and Procedural Background

Company A, a pharmaceutical enterprise based in The Netherlands, and Company B, a United Kingdom pharmaceutical enterprise, each discovered in 1997 that paroxetine methanesulfonate (“PMS”) possessed advantages over the previously marketed hydrochloride salt of paroxetine. Company A filed an international patent application on 10 June 1997 claiming, among other things, crystalline PMS. Company B filed a later United Kingdom patent application, eventually granted as UK Patent No 2 336 364, whose principal claim covered a specific crystalline form of PMS identified by infrared (IR) and X-ray diffraction (XRD) peaks.

On 7 March 2001 Company A commenced revocation proceedings, alleging that Company B’s patent lacked novelty under sections 1 and 2 of the Patents Act 1977 because the invention had already been disclosed—and enabled—by Company A’s earlier PCT application (a “section 2(3)” citation). Judge Jacob agreed, revoked the patent, and held that the crystalline form claimed by Company B was anticipated.

Company B appealed. The Court of Appeal (Judges Aldous, Sedley and Rix) reversed, holding that the earlier application neither clearly disclosed nor enabled the patented invention. Company A appealed to the House of Lords, which delivered the present opinion.

Legal Issues Presented

1. Whether Company A’s earlier patent application “disclosed” an invention that, if performed, would necessarily infringe Company B’s patent claim to crystalline PMS.
2. Whether that earlier disclosure was “enabled,” i.e., whether a person skilled in the art could have made crystalline PMS using the information in the application together with common general knowledge.
3. Whether the Court of Appeal erred by conflating the separate legal tests of disclosure and enablement.

Arguments of the Parties

Company A's Arguments

• The earlier PCT application identified crystalline PMS of 98 % purity; given the judge’s finding that PMS is monomorphic, any crystalline PMS must possess the IR/XRD characteristics claimed by Company B.
• The inaccurate IR spectrum in the PCT application was a laboratory error and irrelevant once monomorphism is accepted.
• Although the specific worked example used ethanol (an unsuitable solvent), a skilled chemist could readily choose alternative solvents through routine experimentation, as crystallisation is “an art.”
• Therefore both disclosure and enablement requirements were satisfied, making Company B’s patent invalid for lack of novelty.

Company B's Arguments

• The IR peaks in the earlier application differed from those in the patent, indicating disclosure of a different polymorph and hence no anticipation.
• The example in Company A’s application failed to yield crystals; enabling disclosure therefore was absent.
• The experimentation necessary to obtain the patented form would amount to an inventive step, not simple routine work.
• Judge Jacob erred in crediting evidence that relied on hindsight of the patent and on expertise exceeding that of the notional skilled person.

Table of Precedents Cited

Court's Reasoning and Analysis

Judge Hoffmann, writing for the majority, separated the appeal into two discrete questions:

1. Disclosure. The earlier application unquestionably taught the existence of crystalline PMS of 98 % purity. Given the trial finding that PMS is monomorphic, any crystalline PMS—regardless of erroneous IR data in the application—would inherently possess the IR/XRD profile claimed by Company B. Therefore performance of the earlier disclosure would necessarily infringe the patent.
2. Enablement. The fact that the worked example used an unsuitable solvent (ethanol) did not defeat enablement. Crystallisation is a routine skill; the skilled chemist would, by ordinary techniques and alternative solvents listed in the application or known in common general knowledge, obtain crystals within a reasonable time. Judge Jacob’s factual finding on this point was entitled to deference under Biogen principles.

The House found that the Court of Appeal had blurred disclosure and enablement, relying on factors relevant to one test when analysing the other. Once the two concepts were kept distinct, the earlier application both disclosed and enabled the invention claimed in the patent. Consequently, anticipation was established.

Holding and Implications

APPEAL ALLOWED; DECISION OF JUDGE JACOB RESTORED.

Company B’s patent is invalid for lack of novelty. The judgment reinforces the necessity of analysing “disclosure” and “enablement” as separate legal requirements. It clarifies that inaccuracies in non-essential descriptive data (such as an IR spectrum where a compound is monomorphic) do not negate disclosure, and confirms that routine experimentation does not defeat enablement. The ruling brings United Kingdom practice into line with European Patent Office jurisprudence but is confined to the statutory novelty context and does not establish a new cause of action.