New Breast Cancer Drug to Enter Marketing Regulatory Process

The developers of a drug designed to replace Herceptin (trastuzumab) for treatment of metastatic breast cancer have released results from a successful phase III clinical trial and expect that the compound will obtain US and European marketing approval in 2013.

The drug, T-DM1 (trastuzumab emtansine), consists of the Immunogen (Waltham, MA, USA) DM1 cancer-killing agent mertansine attached to the HER2-binding antibody, trastuzumab, developed by the Roche (Basel, Switzerland) subsidiary Genentech (San Francisco, CA, USA).

Synthesis of the compound was accomplished using 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 a highly potent cancer-killing agent 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 this technology (including T-DM1), the antibody component also has meaningful anticancer activity.

T-DM1 is being evaluated for the treatment of HER2+ metastatic breast cancer in three phase III trials: EMILIA, MARIANNE, and TH3RESA. Results have now been released for EMILIA, the lead trial, which evaluated T-DM1 as a treatment for patients that previously were treated with Herceptin and with a taxane in any setting.

Results were released from the 991-person, randomized, open-label phase III EMILIA study, which compared the efficacy of T-DM1 to the combination of the GlaxoSmithKline (Brentford, United Kingdom) drug Tykerb (lapatinib) and Roche/Genentech’s Xeloda (capecitabine) in patients with HER2+ locally advanced or metastatic breast cancer previously treated with Herceptin and chemotherapy. The findings showed that T-DM1 offered a “significant” overall survival increase to patients with metastatic breast cancer.

Considering the results of this analysis, EMILIA patients taking Tykerb/Xeloda will be offered the option to switch to T-DM1.

Genentech announced that it has filed a Biologics License Application (BLA) to the [US] Food and Drug Administration (FDA), and Roche is planning to submit a Marketing Authorization Application to the European Medicines Agency in the near future. Based on the excellent EMILIA results the drug is expected to receive FDA approval as early as the second quarter of 2013, although European approval is unlikely before the last quarter of 2013.

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