Filgotinib is a selective JAK1 inhibitor, potentially best-in-class

Due to its high selectivity for Janus kinase 1, or JAK1, we believe that filgotinib has the potential to offer an improved side effect profile and improved efficacy in RA patients as compared to other JAK inhibitors which are less selective for JAK1. Filgotinib has been evaluated for RA in two Phase 2b trials and is currently being evaluated in an ongoing, follow-up trial, which trials we refer to collectively as DARWIN. These studies recruited patients with moderate to severe RA who have an inadequate response to methotrexate, or MTX, a common first line treatment for RA. Final results from 24 weeks of treatment in our Phase 2b trial for DARWIN 1 were disclosed on July 29, 2015. Final results from 24 weeks of treatment in our Phase 2b DARWIN 2 trial were disclosed on August 10, 2015. In addition, we are conducting DARWIN 3, an ongoing, long-term follow-up trial that allows patients to remain on filgotinib treatment. Of the patients who have completed DARWIN 1 and DARWIN 2 and were eligible to continue, approximately 98% elected to participate in the DARWIN 3 follow-up trial.