ABLYNX'S PARTNER SHOWS THAT A NANOBODY CAN ELICIT SUPERIOR ANTI-TUMOUR EFFICACY COMPARED TO CONVENTIONAL MONOCLONAL ANTIBODY APPROACHES

4 april 2012 Pre-clinical data presented at AACR in Chicago GHENT, Belgium, 4 April 2012 - Ablynx [Euronext Brussels: ABLX] today noted that a paper on a novel tetrameric Nanobody(®) agonist (TAS266) targeting Death Receptor 5 (DR5), a key receptor target on cancer cells across a number of tumour types, was presented at the American Association for Cancer Research Annual Meeting in Chicago, USA, on 3 April 2012 by Novartis. The ability of TAS266 to efficiently 'cross-link' DR5 receptor targets, apparently not achievable with conventional monoclonal antibodies, results in the controlled death of cancer cells. The paper was presented by Dr Heather Huet from Novartis and the authors included three scientists from Ablynx. The abstract summarizes the results of the pre-clinical in vitro and in vivo studies of a tetravalent anti-DR5 Nanobody in an oncology setting. TAS266 was shown to elicit sustained tumour regressions in multiple tumour xenograft models, including a patient-derived primary pancreatic tumour model that is insensitive to a conventional anti-DR5 agonist antibody. Also, compared to some of the other therapeutic agonists against DR5 that have been developed and that have been clinically evaluated, TAS266 proved to be up to 1000-fold more potent in tumour cell death assays. In view of this, the authors of the abstract conclude that "TAS266 has the potential for superior clinical activity in settings insensitive to the conventional therapeutic approaches to DR5." The abstract further states that "first-in-man trials for TAS266 are expected to begin in 2012." Link to the presentation abstract: "TAS266, a novel tetrameric Nanobody agonist targeting death receptor 5 (DR5), elicits superior anti-tumour efficacy than conventional DR5-targeted approaches." Commenting on today's announcement, Dr Edwin Moses, Chairman and CEO of Ablynx, said: "Being present on cancer cells across a broad range of tumour types, DR5 has been the target of numerous conventional antibody approaches, but none have apparently been successful so far, possibly because of the need for secondary 'cross-linking' to achieve the required activity. The ability to produce tetravalent Nanobodies appears to allow more efficient 'cross-linking' (in the tumour micro-environment) and so potentially opens up a new pathway for the treatment of certain cancers." About Ablynx Ablynx is a biopharmaceutical company engaged in the discovery and development of Nanobodies(®), a novel class of therapeutic proteins based on single-domain antibody fragments, for a range of serious and life-threatening human diseases, including inflammation, haematology, oncology and pulmonary disease. Today, the Company has over 25 programmes in the pipeline and seven Nanobodies at clinical development stage. Ablynx has ongoing research collaborations and significant partnerships with major pharmaceutical companies, including Boehringer Ingelheim, Merck Serono and Novartis. The Company is headquartered in Ghent, Belgium. More information can be found on www.ablynx.com. For more information, please contact Ablynx: Dr Edwin Moses Chairman and CEO t:   +32 (0)9 262 00 07 m: +44 (0)7771 954 193 /      +32 (0)473 39 50 68 e:  edwin.moses@ablynx.com Marieke Vermeersch Investor Relations Manager t:   +32 (0)9 262 00 82 m: +32 (0)479 49 06 03 e:  marieke.vermeersch@ablynx.com M:Communications: Mary-Jane Elliott, Amber Bielecka, Claire Dickinson t:   +44 207 920 2330 e:  ablynx@mcomgroup.com Complete version of the press release: http://hugin.info/137912/R/1599977/504947.pdf This announcement is distributed by Thomson Reuters on behalf of Thomson Reuters clients. The owner of this announcement warrants that: (i) the releases contained herein are protected by copyright and other applicable laws; and (ii) they are solely responsible for the content, accuracy and originality of the information contained therein. Source: Ablynx via Thomson Reuters ONE [HUG#1599977]