Alexion adds to rare disease pipeline

Projects targeting the neonatal Fc receptor (FcRn) are already attracting much attention: Argenx’s efgartigimod, which only recently moved into phase III, has already attracted blockbuster sales forecasts. So Alexion’s swoop on Syntimmune today, for $400m up front, could yet be seen as a bargain; the private biotech’s anti-FcRn antibody SYNT001 is one of the few assets in the class in clinical trials. Aggressive clinical plans for the project were unveiled: even though a phase Ia/IIb trial has yet to be completed, pivotal studies in warm autoimmune haemolytic anaemia (WAIHA) and another as-yet-undisclosed indication will commence next year. In terms of the competition, executives pointed to SYNT001’s fast onset of action and what could be a lower potential for immunogenicity than other agents in development. Many of the illnesses being pursued by developers of anti-FcRn agents are chronic, so confirmation of long-term safety and tolerability remains crucial. However, the mechanism could plausibly revolutionise the treatment of a broad range of IgG-mediated autoimmune conditions, so the enthusiasm here is understandable. As owners of the only unencumbered clinical stage assets – assuming Argenx is intent on going it alone – Momenta and Affibody could well start to attract more interest.