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Tuesday, 30 June 2015

Patent Déjà vu - Hospira v Genentech and another patent dies

There has been a superabundant deluge of patent cases last week, with two decisions from the Court of Appeal and two from the Patents Court.  So it is with slight delay that the IPKat comes to the latest decision in the apparently endless Hospira v Genentech saga.  Hospira is seeking to invalidate all of Genentech's secondary patents relating to the cancer drug trastuzumab (Herceptin) so that it can market a generic version now that the SPC for the basic patent has expired.

Two patents were killed off in the first action (reported here and confirmed on appeal here).  Another two were killed off as reported here (some claims survived in one patent, but these are apparently not of concern to Hospira); this is currently under appeal.

The present case Hospira UK Ltd v Genentech Inc [2015] EWHC 1796 (Pat) concerns EP (UK) 1037926, which concerns a combination of trastuzumab with another favourite of pharmaceutical litigation, taxol (and other taxanes).  The unbrief main Swiss claim (there was also a claim in the EPC 2000 format) as granted reads (with the integer numbering adopted by the Court):

[1] Use of an anti-ErbB2 antibody in the preparation of a medicament
[2] for treatment to provide clinical benefit as measured by increased time to disease progression of malignant breast cancer characterised by overexpression of ErbB2 in a human patient,
[3] wherein said antibody binds to epitope 4D5 within the ErbB2 extracellular domain sequence as determined by a cross-blocking assay using said antibody and antibody 4D5 obtainable from deposit ATCC CRL 10463,
[4] and wherein the method comprises combined administration of the antibody with a chemotherapeutic agent which is a taxoid and not in combination with an anthracycline derivative,
[5] wherein the combined administration has:

[a] clinical efficacy as measured by determining time to disease progression and

[b] reduced myocardial dysfunction compared with combined administration of the antibody and anthracycline derivatives.

Mr Justice Arnold construed the claim as requiring by integer [2] that it is known to, or reasonably foreseeable by, the manufacturer of the medicament that the antibody will be intentionally administered in combination with a taxane for the relevant therapeutic purpose.  He also construed that integer as requiring that the combination of antibody and taxane be more effective than the taxane alone, resulting in an increased time to disease progression (abbreviated as TTP).

There was only one piece of prior art to consider -  Baselga et al, "HER2 Overexpression and Paclitaxel Sensitivity in Breast Cancer: Therapeutic Implications", Oncology, 11, Supp. 2, 43-48 (March 1997) ("Baselga 97").  This describes, among other things, a Phase III trial of trastuzumab in combinations with paclitaxel and other agents, but does not disclose any results from that trial, but it does disclose the results from the Phase I and II studies.

The judge considered that Baselga 97 did not enable the clinical benefit claimed in the Patent to be directly and unambiguously derived, and therefore that the claim was novel.

Turning to inventive step, Arnold J set out that the authorities required "a reasonable or fair expectation of success" for a claim to be obvious.  Thus he considered the issue to be whether the skilled person would have a fair expectation of success, meaning a fair expectation of increased efficacy as measured by TTP of the combination compared to taxane alone, if he were to undertake the phase III trial.  Even though the results of the trial were not disclosed in Baselga 97, because it was ongoing, the judge found that the results that were in the document, in particular that the results of the Phase II trials and the xenograft studies were described as "positive" and "encouraging", would cause the skilled person to have had a reasonable expectation of success in the Phase III trial.

Therefore he found the claim to be obvious.

A relatively brief decision merits a relatively brief report.  One thing that does strike this Kat is that in the first of this series of cases, EP 1 210 115, directed towards a dosage regime of trastuzumab, was held to be invalid on the basis that the skilled person would attempt a trial of the claimed regime; there was no need for a fair expectation of a positive outcome of the trial - only sufficient expectation to actually conduct it.  As far as this Kat can tell, this is because in that case the claim did not recite any clinical benefit, so there was no need for the skilled person to expect one for the claim to be obvious.  But the IPKat would be interested in readers' views.

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