Hospira are interested in selling the breast cancer drug trastuzumab, marketed by Genentech under the trade name Herceptin®. Trastuzumab is a monoclonal antibody that targets the HER2 receptor (a protein on the surface of a cell that affects the cell’s growth) and is approved for use in the treatment of HER2+ breast cancer (i.e. breast cancer in which the breast cancer cells have a high number of HER2 receptors causing the cells to divide and grow quickly). Genentech’s SPC for its basic t rastuzumab patent is due to expire in July 2014, but Genentech had additional patent protection for t rastuzumab in the form of EP 1210115, which relates to do sage regimes, and EP 1 308 455, which relates to a composition of trastuzumab with low levels of impurities. Hospira brought a revocation action against both EP 1210115 and EP 1 308 455. The following discussion focusses on EP 1210115. EP 1210115 claimed an initial dose of 8 mg/kg of body weight and a plurality of subsequent doses of 6 mg/kg of body weight; the doses being administered every three weeks, summarised as 8 + 6 q3w. Hospira asserted that this claim was invalid for obviousness and/or lack of sufficiency.