arGEN-X’ Core Patents Protecting Lead Clinical Candidates ARGX-110 and ARGX-111 Receive Accelerated Grant in the United States

Breda, the Netherlands / Ghent, Belgium– arGEN-X N.V. (Euronext Brussels: ARGX), a clinical-stage biopharmaceutical company focused on creating and developing differentiated therapeutic antibodies for the treatment of cancer and severe autoimmune diseases, is pleased to announce the grant of key patents in the United States relating to its two lead clinical candidates ARGX-110 and ARGX-111.

The US Patent & Trademark Office (USPTO) granted composition-of-matter claims relating to ARGX-110, a novel SIMPLE Antibody™ product targeting human CD70. The issued patent (US 8,834,882) was examined by the USPTO’s Track 1 Prioritized Examination Program leading to a patent grant within ten months of filing. This grant is in addition to the recent grant of an arGEN-X patent (US 8,637,027) relating to ARGX-111, a proprietary SIMPLE Antibody™ targeting human c-Met. Both patent rights are projected to expire in 2031-2032 but are eligible for up to an additional five years of Patent Term Extension for marketing delays caused by necessary clinical trials and FDA regulatory review.

In addition to securing core composition of matter patent rights for its antibody products, arGEN-X is pleased to announce the grant of an additional patent (US 8,835,607) relating to its SIMPLE Antibody™ platform technology involving broad patent claims relating to arGEN-X’ germlining approach for SIMPLE Antibodies. This granted patent serves to supplement arGEN-X’ growing portfolio of issued patents relating to its proprietary SIMPLE Antibody™ platform (e.g. US Patents 8,444,976 and 8,524,231). Not only do these platform patents provide exclusive composition-of-matter coverage for the development of SIMPLE antibodies, they provide supplementary patent protection for both ARGX-110, ARGX-111 and other SIMPLE antibodies in arGEN-X’ pipeline.

Tim Van Hauwermeiren, CEO of arGEN-X, said: The grant of these patents in the US is an important milestone for arGEN-X that provides validation for our technology and patent strategy. We believe our pipeline has considerable commercial potential and these patents in the world’s largest pharmaceutical market give us confidence that we can generate significant shareholder value from these unique therapeutic antibodies as they advance.