On Mar. 6, 1991, Immunex announced it had received U.S. Food and Drug Administration (FDA) approval to market Leukine (GM-CSF in the U.S. to treat bone marrow transplant patients. GM-CSF (marketed as Leukine), was a blood-growth stimulator that enhanced the body’s production of white blood cells.

Leukine is a yeast-derived recombinant human granulocyte-macrophage colony stimulating factor (GM-CSF). Leukine was initially approved in the United States  and has five hematology oncologic indications. The development of the H-ARS indication was funded completely with Federal funds from the Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authorit.

Leukine received orphan designation for H-ARS in the U.S. in November 2016 and in April 2018 was granted 7 years exclusivity period for this indication. A supplemental biologics licensing application (sBLA) was filed with FDA in September 2017 requesting approval of Leukine for treatment of H-ARS. In December, the application was granted Priority Review

In 2018, Boston-based cancer company Partner Therapeutics (PTX) acquired the global rights to develop, manufacture, and commercialize Leukine (sargramostim) from Sanofi.

PTx is an integrated commercial-stage biotech company focused on the development and commercialization of therapeutics that improve health and economic outcomes in the treatment of cancer. PTx’s development focus spans the entire range of cancer therapy from primary treatments to supportive care.