ABLYNX INITIATES PHASE II SLE STUDY WITH ITS ANTI-IL-6R NANOBODY, PARTNERED WITH ABBVIE

Phase II study to evaluate the efficacy and safety of ALX-0061, administered subcutaneously, in patients with moderate to severe, active systemic lupus erythematosus (SLE)

GHENT, Belgium, 4 August 2015 - Ablynx [Euronext Brussels: ABLX; OTC: ABYLY] today announced that it has administered the first dose in the Phase II STEADY study to evaluate the efficacy and safety of its anti-IL-6R Nanobody®, ALX-0061, administered subcutaneously in adult patients with moderate to severe, active seropositive SLE, despite receiving the standard-of-care. The study also aims to identify the optimum dose and frequency of administration of ALX-0061 for the next phases of development.

In September 2013, Ablynx and AbbVie entered into a global license agreement, worth up to US$840 million plus double-digit royalties, to develop and commercialise ALX-0061. As part of the agreement, Ablynx is responsible for Phase II clinical development of ALX-0061 in rheumatoid arthritis and systemic lupus erythematosus.

This Phase II study in SLE is a multi-centre, randomized, double-blind, placebo-controlled, dose-range finding study. It is expected to enrol approximately 300 subjects in the United States, Europe, South America and Asia, who will be randomly assigned to placebo or one of the four different dose groups of ALX-0061. Subjects will be followed for efficacy up to and including week 48 and for safety up to and including week 58.

The study's primary endpoint is the percentage of subjects who achieved a response at week 24 according to the composite BICLA score (BILAG-based Combined Lupus Assessment). This is a broadly accepted, sensitive, clinically meaningful composite measure of SLE disease activity that requires disease improvement across all body systems with moderate or severe baseline activity without concurrent worsening in other body systems or increase in background medication. The secondary endpoints include the composite systemic lupus erythematosus responder index (SRI), the individual components of the composite endpoints, as well the effects of ALX-0061 on health-related quality of life, flare rate and use of corticosteroids. Other planned assessments include the determination of ALX-0061 levels, biomarkers, safety, tolerability and immunogenicity.