The English high court recently gave its decision in a patent case, clearing the way for a UK launch of a generic version of Genentech/Roche’s breast cancer treatment, Herceptin, later this year. Two patents relating to the breast cancer monoclonal antibody drug trastuzumab, sold as Herceptin, were challenged. This antibody, developed by Roche and Genentech, targets the HER2 receptor and has proven to be an effective treatment for certain types of breast cancer.
Herceptin is reportedly the the 10th best-selling drug in the world with sales of over $6 billion in 2013. This is clearly a worthwhile prospect for a generic manufacturer, even with the added complexity of bringing a biological drug to market. Hospira will now be able to enter the market once Genentech’s underlying patent (with its supplementary protection certificate) expires on 28 July.
Hospira did not challenge the underlying patent, but two later patents dealing with dosage regimes and purified compositions. The dosage regime patent (EP 0 210 115) and the composition patent concerning a composition with low impurity levels (EP 1 308 455), if valid, could provide several years more cover for Herceptin. Both patents were found invalid on opposition by the European Patent Office, but those decisions are currently on appeal.
The dosage regime patent claimed 8mg/kg given intravenously, followed by 6mg/kg doses at 3-weekly intervals. The UK judge said that this was obvious over the FDA-approved treatment regime shown on the product label. At the relevant time, it would be routine for a clinician in oncology to think about improving a patient’s quality of life by considering the dosage regime. And, if the patent were not obvious, it gave inadequate information about the dosage regime to use.
The composition patent claimed trastuzumab that had been purified to the extent that the amount of a degraded version of the antibody was limited to less than about 25%. The judge said that this was invalid because of information that had already been disclosed in an earlier Genentech patent application, as well as a 1996 conference presentation given by a Genentech scientist. He also concluded that the Hospira product did not fall within the claims of the composition patent as it contained slightly higher levels of variant antibody.
Although the additional patents that Genentech filed have been found invalid, at least in the UK, the decision demonstrates how effective it can be for an innovator company to file a series of additional patents around a product in order to maintain exclusivity once a main patent expires. Given the length of time it takes to bring a drug to market, particularly a biological, the 20 year period of patent exclusivity may be expiring just when product sales are at their peak. The task of clearing a path through additional patents covering other aspects of the product can be an difficult and expensive one for portential competitors.