Prima BioMed Ltd, a globally active biotechnology company that is striving to become a leader in the development of immunotherapeutic products, announced that the European Patent Office has granted patent number 2142210 entitled "Cytotoxic anti-LAG-3 monoclonal antibody and its use in the treatment or prevention of organ transplant rejection and autoimmune disease."

The patent relates to Prima's IMP731 antibody (originally developed by Immutep SAS). The granted claims provide protection for specific sequences of anti-LAG-3 antibodies and their use in depleting LAG-3+ T cells by complement dependent cytotoxicity (CDC) and antibody-dependent cell cytotoxicity (ADCC).

Rights for the development of the IMP731 antibody were granted in December 2010 to GSK, which has commenced first-in-human clinical trials of the proprietary antibody (GSK2831781) derived from IMP731.

IMP731 and GSK2831781 are designed to specifically deplete potentially pathogenic, recently activated, LAG-3 expressing T cells which are enriched at the disease site in T-cell driven immuno-inflammatory disorders and should spare other T-cells which may be necessary for other functions.

Under the terms of the 2010 agreement between Immutep and GSK, GSK has responsibility for all development and associated costs for GSK2831781. Prima BioMed may receive payments and potential milestones totalling up to £ 64 million and is eligible for single-digit, tiered royalties if all objectives are achieved.