REGENXBIO's Rollercoaster Ride: A Tale of Two Gene Therapies A Glimmer of Hope: World's First Gene Therapy Trial Fights Blindness FDA Pumps the Brakes: Denali Therapeutics' Hunter Syndrome Drug Faces Extended Review FDA Extends Review for Denali's Hunter Syndrome Breakthrough: A Closer Look at Tividenofusp Alfa's Path to Approval