Less than a year after its launch in 2013, Dimension Therapeutics has secured its first big pharma partner by agreeing to collaborate with Bayer to develop and commercialise a preclinical-stage gene therapy programme for haemophilia A. Bayer has considerable expertise in this disease area thanks to its Kogenate® (recombinant antihaemophilic factor VIII) franchise. The deal marks a return to the gene therapy field for the German company, coming 18 years after it licensed an ultimately unsuccessful haemophilia A gene therapy from Immune Response.