Roche has Phase III trials underway evaluating trastuzumab emtansine both for newly diagnosed and for previously treated metastatic HER2-positive breast cancer. Additionally, it plans to initiate registration trials beginning in 2013 to evaluate the compound for three settings in earlier-stage disease: adjuvant use; neoadjuvant use; and treatment of patients with residual invasive disease following standard neoadjuvant therapy.About ImmunoGen’s TAP Technology A TAP compound consists of a monoclonal, or manufactured, antibody that binds specifically to a target found on tumor cells with one of the Company’s highly potent cancer-killing agents attached as a payload. The antibody serves to target the payload specifically to the cancer cells, and the payload serves to kill the cancer cells. In the case of some compounds that use ImmunoGen’s TAP technology (trastuzumab emtansine and ImmunoGen’s IMGN529 compound), the antibody component also has meaningful anticancer activity. About ImmunoGen, Inc. ImmunoGen, Inc. develops targeted anticancer therapeutics using the Company's expertise in tumor biology, monoclonal antibodies, potent cancer-cell killing agents and engineered linkers. The Company's TAP technology uses monoclonal antibodies to deliver one of ImmunoGen's proprietary cancer-killing agents specifically to tumor cells. There are now ten TAP compounds in clinical development, of which three are wholly owned by the Company. A marketing application for trastuzumab emtansine (T-DM1), the most advanced compound using ImmunoGen's TAP technology, has been submitted in the US. Roche is developing this compound globally under an agreement between ImmunoGen and Genentech, a member of the Roche Group. More information about ImmunoGen can be found at www.immunogen.com. This press release includes forward-looking statements. For these statements, ImmunoGen claims the protection of the safe harbor for forward-looking statements provided by the Private Securities Litigation Reform Act of 1995. It should be noted that there are risks and uncertainties related to the development of novel anticancer products, including trastuzumab emtansine (T-DM1), including risks related to clinical studies and regulatory submissions, their timings and results. A review of these risks can be found in ImmunoGen’s Annual Report on Form 10-K for the fiscal year ended June 30, 2011 and other reports filed with the Securities and Exchange Commission. 1ASCO June 2012 (abstract #LBA1). Tykerb® is a registered trademark of GlaxoSmithKline plc. Xeloda® is a registered trademark of Roche. Herceptin® is a registered trademark of Genentech, a member of the Roche Group.