Actavis Group PTC EHF & Anor v Eli Lilly and Company

For a second medical use claim, therapeutic efficacy is a functional technical feature. The claimed treatment need not succeed in every patient, but the medicament must produce a discernible beneficial effect in the relevant patient class.

Obviousness requires assessment of the claimed invention against the prior art, using the knowledge and attitudes of the skilled team at the priority date. An obvious-to-try argument must be assessed as part of the overall inventive-step inquiry and ordinarily requires a fair expectation of success.

Plausibility is a threshold requirement considered within the statutory grounds of validity. It excludes speculative claims based on mere assertion, but its standard is distinct from the fair-expectation-of-success standard for obviousness. A narrow therapeutic claim may be plausible without experimental data where the specification and common general knowledge provide a credible basis.

Actavis sought revocation of a patent owned by Eli Lilly concerning the use of atomoxetine for treating attention-deficit/hyperactivity disorder. Lilly counterclaimed for threatened infringement.

The patent claimed a second medical use in Swiss form. Actavis alleged lack of inventive step over two prior-art publications, Chouinard and Zerbe, and challenged plausibility, sufficiency and entitlement to priority. Actavis also alleged a squeeze between lack of inventive step and lack of plausibility.

The central issues were whether the skilled team would have been led to try atomoxetine for ADHD with a fair expectation of success, and whether the patent made that therapeutic use plausible despite the absence of clinical data in the specification.

1. Outcome. The claim for revocation was dismissed. The patent was held valid. Lilly’s counterclaim for threatened infringement succeeded.
2. Skilled team and common general knowledge. The skilled team comprised a clinician, particularly a child and adolescent psychiatrist with expertise in ADHD, and a basic psychopharmacologist. The clinician would take the leading role in evaluating the significance of pharmacological information. At the priority date, the team would regard selective norepinephrine reuptake inhibition as a reasonable hypothesis concerning tricyclic antidepressants, but would remain uncertain about downstream mechanisms, the direction of norepinephrine activity, and the involvement of other neurotransmitters.
3. Inventive step. The proper question was whether the invention specified in the claims was obvious, not whether the specification contained extensive experimental disclosure. Applying the structured approach in Pozzoli SpA v BDMO SA [2007] FSR 37, neither Chouinard nor Zerbe made it obvious to try atomoxetine for ADHD. Both concerned depression or healthy volunteers, involved small numbers and lacked placebo controls. Even if it had been obvious to try atomoxetine, the skilled team would not have had a fair expectation that it would be discernibly effective for ADHD.
4. Plausibility and sufficiency. Plausibility was not a separate ground of invalidity. It operated within the statutory requirements of patentability and was a threshold safeguard against speculative patents. Its standard was not the same as the fair-expectation-of-success standard for obviousness. The patent’s disclosure, read with the common general knowledge and the supporting material concerning atomoxetine’s selective norepinephrine reuptake inhibition, made the claimed therapeutic effect credible. Post-published evidence could confirm that conclusion.
5. Swiss-form claim. In a Swiss-form claim, attaining the therapeutic effect is a functional technical feature. The word “for” concerns the manufacturer’s knowledge or reasonable foreseeability of the intended use. That infringement construction did not establish the standard of plausibility for sufficiency. Treatment need not succeed in every patient, but the medicament must have a discernible beneficial effect in the relevant class.
6. The alleged squeeze between obviousness and insufficiency therefore failed. The attacks based on lack of plausibility and loss of priority also failed.