Joining the likes of Janssen, Eli Lilly and Regeneron, Mallinckrodt has now ventured into the field of RNAi therapeutics with a potential US$2.1 B collaboration with Silence Therapeutics. The two companies will first look at advancing SLN500 for the treatment of complement-mediated diseases; Silence will be responsible for the asset up to Phase I, after which Mallinckrodt will undertake clinical development and beyond. The deal comes as Mallinckrodt faces ongoing troubles with its leading revenue generator, Acthar® (corticotropin), including revenue declines and ongoing litigation.