“Skinny labelling” fails: pharmaceutical generic patent indirect infringement victory overturned
In a unanimous decision handed down on 19 May 2014 in Warner-Lambert Co LLC v Apotex Pty Ltd  FCAFC 59 (Warner-Lambert), the Full Court made it clear that the so-called “skinny labelling” tactic of registering pharmaceutical products for indications that are different to those claimed in method of treatment patents, even if accompanied by pro forma letters to doctors and pharmacists recommending use confined to the registered indications, will not necessarily avoid findings of indirect patent infringement by supply. The Full Court indicated that indirect patent infringement will not be avoided if the weight of evidence suggests that the supplier has “reason to believe” that the supplied pharmaceutical will be put to the claimed use. In making this finding the Full Court has breathed renewed life into section 117(2)(b) of the Patents Act 1990 (Cth) (section 117(2)(b)) and affirmed it as an important weapon in the innovator company’s armoury.
Contributory patent infringement by supply with “reason to believe”
Relevantly, section 117(2)(b) provides that if the use of a product by a person would infringe a patent, the supply of that product by one person to another is an infringement of the patent by the supplier if the product is not a staple commercial product and the supplier had reason to believe that the person would put it to that use.
Possible avoidance of contributory patent infringement using “skinny labelling”
Following the decision of the High Court in Apotex Pty Ltd v Sanofi-Aventis Australia Pty Ltd  HCA 50 (Sanofi), it was widely considered that contributory infringement pursuant to section 117(2)(b) might be avoided by obtaining ARTG registration of pharmaceutical products for indications different from those claimed in the asserted patent (a practice known as “skinny labelling”).
In Sanofi, the Apotex approved Product Information Sheet stated that Leflunomide was indicated for the treatment of active rheumatoid arthritis or active psoriatic arthritis, but not indicated for the treatment of psoriasis that was not associated with manifestations of arthritic disease.
Even though the evidence was that Leflunomide could be used in the treatment of psoriasis not associated with manifestations of arthritic disease in addition to active rheumatoid arthritis or active psoriatic arthritis, the High Court held on the evidence that Apotex had no “reason to believe” that medical practitioners would use Leflunomide for the claimed purpose being the prevention and treatment of psoriasis, in contravention of section 117(2)(b).
ARTG indication limitations and announcement letters to users may not suffice
In Warner-Lambert, Apotex obtained ARTG registrations for various pharmaceutical products containing pregabalin as the active ingredient limited to the treatment of neuropathic pain (neuropathic pain) and adjunctive therapy in adults with partial seizures (seizure indication). Subsequently, Apotex amended its registration and product information to confine its registration to the seizure indication. At the conclusion of an interlocutory injunction application, after noting that it was not suggested by Apotex that pregabalin was a “staple commercial product” and that Apotex did not oppose an interlocutory injunction restraining Apotex from supplying any product containing pregabalin for the treatment of neuropathic pain in adults, the duty judge refused to restrain supply of pregabalin for the seizure indication. In doing so the duty judge concluded that a prima facie case of “reason to believe” that pregabalin would be prescribed and used in the treatment of neuropathic pain within the meaning of section 117(2)(b) had not been established to the requisite level.
Apotex’s skinny labelling strategy fails to avoid interlocutory injunction
The Full Court overturned the duty judge’s decision, finding that:
- in assessing the strength of Warner-Lambert’s prima facie case the duty judge had erroneously failed to give proper weight to the Warner-Lambert evidence that the seizures indication market was practically non-existent and that doctors and pharmacists might well prescribe Apotex’s bio-equivalent product “off-label” for neuropathic pain regardless of the Apotex limited ARTG registration and pro forma letters; and
- the balance of convenience, coupled with a stronger prima facie case than was found to exist by the duty judge, also favoured Warner-Lambert.
As a consequence the Full Court extended the interlocutory injunction to cover all Apotex’s products containing pregabalin.
This decision not surprisingly demonstrates that if there exists clear and convincing evidence that the supplier had “reason to believe” that the supplied active substance would be put to the infringing use, “skinny labelling” strategies such as formulaic registration limitations and announcement letters to doctors and pharmacists may not be enough to prevent the patent owner discharging the evidentiary burden necessary to establish contributory infringement.