ImmunoGen Inc of Waltham, Massachusetts has reported initial data from two early clinical trials of its antibody-drug conjugate for first-line treatment of breast cancer patients which showed meaningful response rates when the product, trastuzumab-DM1, was used as a single agent, or in combination with a monoclonal antibody. Data from a Phase 1b/2 trial, which was reported on 10 December, showed that 57.1% of patients with HER2 metastatic breast cancer responded to treatment with the drug, plus the antibody (pertuzumab). The study consisted of 21 patients who had not received prior systemic anticancer therapy for metastatic disease. In a separate Phase 2 study, 47.8% of 137 patients receiving trastuzumab-DM1 as a single agent responded to treatment. This compared with a response rate of 41.4% of patients treated with Herceptin and a taxane. The ImmunoGen antibody-drug conjugate consists of trastuzumab plus a cytotoxic agent and a linker.
