On 24 June 2015 the High Court gave its third decision in the long-running dispute between Hospria and Genentech relating to the latter’s patents for Herceptin. On this occasion the patent in this dispute was to the use of the antibody, trastuzumab (the active ingredient in Herceptin) in combination with a taxane in the treatment of HER2-positive breast cancer. Taxanes are a class of chemotherapeutic agents which include paclitaxel and docetaxel.

The attacks on the validity of Genentech’s patent were based on a single piece of prior art called “Baselga 97”. Baselga 97 described a Phase III clinical trial of trastuzumab in combination with different chemotherapeutic agents including paclitaxel. The paper did not disclose any results from the Phase III trial but did contain results from earlier Phase I and II studies.

Before addressing the validity of the patent, Arnold J made several observations on claim construction and infringement; in particular, he held that the reference to “for” in the claim meant that it must be known to, or reasonably foreseeable by, the manufacturer that trastuzumab would be intentionally administered in combination with a taxane for the relevant therapeutic purpose (i.e. for the treatment of HER-2 positive breast cancer).

On the question of novelty, Arnold J noted that purpose limited claims can only be anticipated by (i) the disclosure of the invention or (ii) the disclosure of subject matter which, if performed, would inevitably result in the claimed invention. Whilst arguments under the second of these two heads were the more persuasive in this instance, they did not invalidate the claim - given that the necessary mental element of the claim, i.e. the intention to administer the combination to increase efficacy in the treatment of breast cancer, was missing (as it was not known that this would be the effect before the results of the trial were available), it was not possible for Baselga 97 to anticipate the claim.

On the question of obviousness, Arnold J held that the patent lacked inventive step. In so doing Arnold J observed that even though the results of the Phase III trial were not disclosed in Baselga 97, the skilled person would have had a reasonable expectation of success in the Phase III trial given the positive and encouraging results of the Phase II trials and the xenograft studies described.

This is the third decision of the High Court in this dispute between Hospira and Genentech. As a result of these decisions, Hospira has now “cleared the way” of five of Genentech’s Herceptin patents at first instance.