Are treatment claims plausible, and a Brexit twist

Last year’s Supreme Court’s analysis of second medical use claims gave rise to some confusion, not least because of the differences of opinion expressed by the five judges. We looked at that ruling here, and considered what it means for patent owners and potential infringers.

The Supreme Court's validity analysis has now been applied in a complex case (Lilly v Genentech) involving a patent belonging to Genentech for interleukin-17A/F heterologous peptides and their therapeutic uses. Lilly’s psoriasis treatment, Taltz, contains an antibody to interleukin-17A that also binds to interleukin-17A/F, and Genentech said that this product infringed its patent.

The patent included claims to the polypeptides themselves, to antibodies able to bind to them, and to therapeutic applications. (The claims were heavily amended as part of the litigation.) Lilly applied to have the patent declared invalid, and also asked the court for a declaration that their product does not infringe even if the patent is valid.

Was the psoriasis treatment option plausible?

The obviousness analysis followed a well-trodden path. The use of known methods by a suitably skilled team could have produced the antibodies claimed by Genentech’s patent.

However, the claims directed to the use of the antibodies for the treatment of psoriasis required consideration of the “plausibility” test set out by the Supreme Court in the Warner-Lambert case. There the Supreme Court had decided that if claimed methods of treatment were not plausible, the patent would be invalid for insufficiency. 

Although Genentech’s patent was not for a second medical use of an existing medicine, it did include treatment claims, in both the older “Swiss form”, and the newer EPC 2000 form. It is worth noting that there was no data or evidence in the patent directly linking IL-17A/F to psoriasis.

The judge considered what a dermatologist reading the patent would have known about the treatment of psoriasis at the relevant time (July 2003).  He then assessed whether the psoriasis treatment claims would have been plausible at the time. The answer? No. Important considerations were:

  • a lack of experimental data in the patent
  • no discussion of psoriasis
  • little reference to a connection with psoriasis in the cited literature
  • lower potency of IL-17A/F compared to the better known IL-17A/A
  • a long list of conditions in the patent alongside psoriasis, with no emphasis on psoriasis.

This meant that the psoriasis treatment claims were insufficient and so not valid.

Would Lilly's product infringe if the claims were valid?

Infringement was dealt with more briefly – if the claims in question had been valid, would Lilly’s product have infringed?

The “Swiss form” claims were infringed. The marketing authorisation for Taltz made it clear that it was intended to be used in treating psoriasis, so the difficulties in the Warner-Lambert case around skinny label products for a selection of indications did not arise.

The judge dealt with the EPC 2000 claims (essentially, specified antibodies for use in treatment of diseases, such as rheumatoid arthritis and psoriasis) as indirect infringement. This involves supply of a means relating to an essential element of the invention, with knowledge that it is suitable for that purpose. He was clear that Lilly would infringe in this way, if the claims were valid.

The Supplementary Protection Certificate, and a reference to Europe

A parallel ruling on Genentech’s supplementary protection certificate raised a difficult and commercially important interesting question. Lilly argued that Genentech should not be entitled to apply for an SPC to extend its patent monopoly on the strength of a marketing authorisation granted to a completely separate organisation (Lilly).

This area has been looked at in other cases, but the judge felt that these were not clear enough. In his view, answering this question - an important one for industry as it has the potential to affect many profitable products - required an opinion from the European court. With Brexit looming, he decided to get on with sending the question for EU-level consideration, as it was unclear how long this option would remain open to English judges.

Lessons for patentees

Here is another example of a patent with broad and speculative claims being struck down as insufficient.  While getting the balance right between early filing and a fully fleshed-out patent can be difficult, it seems now that more is expected of patent applicants in supporting their method of treatment claims.

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