ImmunoGen, Inc., a biotechnology company that develops antibody-based targeted anticancer products, announced that the US Food and Drug Administration (FDA) has granted orphan drug designation to its lorvotuzumab mertansine (formerly IMGN901) product candidate when used for the treatment of small-cell lung cancer (SCLC).

Through a separate process, ImmunoGen has received a positive opinion for lorvotuzumab mertansine as an orphan medicinal product for the treatment of SCLC from the European Medicines Agency (EMA) Committee for Orphan Medicinal Products (COMP) and is awaiting final designation from the European Commission. The compound previously was granted orphan drug designation for the treatment of Merkel cell carcinoma in both the US and European Union (EU).

"Lorvotuzumab mertansine has shown encouraging initial activity and tolerability when used as a single agent to treat relapsed SCLC, a very difficult cancer," commented Daniel Junius, president and CEO. "We believe this product candidate has the potential to make a real difference for patients with SCLC, and we're planning to start a trial later this year that assesses the compound, used together with standard care, for first-line treatment of this cancer."

In the US, the Orphan Drug Act is intended to encourage companies to develop therapies for the treatment of diseases that affect fewer than 200,000 people in this country. Orphan drug designation provides ImmunoGen with seven years of market exclusivity that begins once lorvotuzumab mertansine receives FDA marketing approval for the treatment of SCLC. It also provides certain financial incentives that can help support the development of the compound for this indication.

Similarly, in the EU, orphan medicinal product designation is intended to encourage companies to develop therapies for life-threatening or chronically debilitating conditions that affect no more than five in 10,000 people in the EU. Orphan medicinal product designation provides ImmunoGen with ten years of market exclusivity that begins once lorvotuzumab mertansine receives European approval for SCLC. It also enables access to certain financial incentives as well as to protocol assistance.

Lorvotuzumab mertansine is an investigational agent designed to kill cancer cells that express CD56, a protein. It consists of a CD56-binding antibody, lorvotuzumab, with a potent cancer-cell killing agent, DM1, attached using an engineered linker. The compound utilizes ImmunoGen's Targeted Antibody Payload (TAP) technology and is wholly owned by the company.

CD56 is expressed on SCLC, Merkel cell carcinoma, ovarian cancer, carcinoid and other solid tumors of neuroendocrine origin, and lorvotuzumab mertansine is in early clinical testing for the treatment of SCLC, Merkel cell carcinoma and ovarian cancer. CD56 also is expressed on multiple myeloma and certain other haematological malignancies. The compound is in early clinical testing for the treatment of CD56+ multiple myeloma, both when used as a single agent and as part of a combination regimen.

ImmunoGen, Inc. develops targeted anticancer therapeutics using its expertise in cancer biology, monoclonal antibodies and the creation and attachment of potent cancer-cell killing agents.