Hospira UK Ltd v Genentech Inc

A purpose-limited therapeutic claim is not anticipated merely because prior art discloses a proposed or ongoing clinical trial. The claimed therapeutic effect must be directly and unambiguously derivable from the disclosure. Where the claim includes an intended therapeutic purpose, the relevant mental element must also be established.

For obviousness, the question is whether the skilled person would have had a fair expectation of success, not merely a reason to try the proposed route. The assessment is fact-sensitive and takes account of motivation, alternative research routes, burden, risk, scientific context and the predictive value of earlier studies. The claims were novel over the prior art but obvious.

Hospira sought revocation of Genentech’s European Patent (UK) No 1 037 926, concerning the use of trastuzumab with a taxane to treat HER2-positive breast cancer. The attack relied solely on Baselga 97, a review article which described, among other matters, an ongoing Phase III trial of trastuzumab combined with chemotherapy but disclosed no results.

The central issues were whether Baselga 97 disclosed the claimed clinical benefit, including increased time to disease progression, and whether it made the claimed combination obvious to the skilled person. The action was heard at first instance in the Patents Court.

1. Construction. The requirement for clinical benefit and clinical efficacy was a functional technical feature. The reference to increased time to disease progression selected that endpoint as the applicable measure of the claimed benefit. The claim also required the relevant intention that the combination be administered to achieve increased efficacy compared with the taxane alone.
2. Novelty. Following Synthon BV v SmithKline Beecham plc [2005] UKHL 59, anticipation required disclosure and enablement. For this claim, Baselga 97 did not directly and unambiguously disclose the claimed therapeutic effect. The xenograft data, the monotherapy results and the description of the ongoing Phase III trial could create an expectation of success, but did not establish that the combination would produce increased efficacy in humans as measured by time to progression.
3. The alternative argument that carrying out the disclosed trial would necessarily infringe also failed. The claim contained a mental element. A person could not intend to administer the combination to achieve the claimed benefit unless that benefit was known or reasonably foreseeable.
4. Obviousness. The relevant question was whether the skilled person would have had a fair expectation of success in undertaking the Phase III trial, rather than merely a hope of success or a reason to investigate the possibility. The assessment required consideration of all the circumstances, including the strong medical need, the routine nature of the trial, its technical burden, patient risk, available alternatives, the rationale for combination therapy, the previous scientific work and known Phase III failure rates.
5. The skilled person would regard the results reported in Baselga 97 as positive and encouraging. The Phase II monotherapy response rate was disappointing but sufficiently encouraging to justify further trials; the cisplatin combination supplied modest additional optimism; and the xenograft results were striking and promising despite their limited reliability as predictors of human efficacy. The skilled person therefore had a fair expectation of success.
6. The claims were novel over Baselga 97 but obvious in its light. The Patent was invalid.