REGENXBIO Inc. (Nasdaq:RGNX) and AveXis, Inc. (Nasdaq:AVXS) today announced that they have entered into an amendment which expands upon the exclusive, worldwide license agreement they entered into in March 2014 (2014 License Agreement) for the development and commercialization of products to treat spinal muscular atrophy (SMA). AveXis’ initial proprietary gene therapy candidate, AVXS-101, is in a pivotal trial for the treatment of SMA Type 1, and a Phase 1 trial for SMA Type 2. AVXS-101 uses REGENXBIO’s NAV AAV9 vector.