ABLYNX'S FIRST-IN-CLASS WHOLLY-OWNED ANTI-vWF NANOBODY, CAPLACIZUMAB, MAY HAVE THE POTENTIAL TO REDUCE MORBIDITY AND MORTALITY ASSOCIATED WITH ACQUIRED TTP

Additional data from post-hoc analyses of the Phase II TITAN study to be presented at the European Congress on Thrombosis and Haemostasis (ECTH)

GHENT, Belgium, 29 September 2016 - Ablynx [Euronext Brussels: ABLX; OTC: ABYLY] announced that it will today present additional data from post-hoc analyses of the Phase II TITAN study of its wholly-owned Nanobody®, caplacizumab, in patients with acquired thrombotic thrombocytopenic purpura (aTTP), at the first European Congress on Thrombosis and Haemostasis (ECTH), being held from 28-30 September 2016 in The Hague, The Netherlands. Shortly after the conference, the presentation will be available on the Ablynx website under the R&D portfolio section.

Acquired TTP is an acute, ultra-rare, life-threatening blood clotting disorder in which uncontrolled platelet aggregation and microclot formation cause small blood vessel occlusions throughout the body[1], resulting in thrombotic complications and widespread organ damage[2]. Despite the current standard-of-care treatment of daily plasma exchange (PEX) and immunosuppression, episodes of aTTP are still associated with a mortality rate of up to 20%, with most deaths occurring within 30 days of diagnosis[3]. Furthermore, patients are at risk of acute thromboembolic complications (e.g. stroke, venous thrombosis and myocardial infarction) and of recurrence of disease. In addition, some patients are refractory to therapy[4], which is associated with a very poor prognosis for survival of an acute episode of aTTP. Data from the French Reference Center for Thrombotic Microangiopathies showed that 50% of patients who died from an acute episode were refractory to treatment[5].

Post-hoc analyses of the Phase II TITAN study data were performed to assess the impact of caplacizumab on a composite endpoint of major thromboembolic complications and aTTP-related mortality, as well as on refractoriness to standard treatment. The results demonstrate that a clinically meaningful lower proportion of subjects treated with caplacizumab experienced one or more major thromboembolic events, or died, as compared to placebo (11.4% versus 43.2%). In addition, fewer caplacizumab-treated patients, compared to those who received placebo, were refractory[6] to treatment (5.7% versus 21.6%; and 0% versus 10.8%, respectively depending on the definition of refractoriness4). There were two deaths in the placebo group and both those patients were refractory to treatment; no deaths were reported in the caplacizumab group.

A Phase III confirmatory study of caplacizumab is currently ongoing which includes prospectively defined assessments of these clinically relevant endpoints.