Audentes Therapeutics, Inc. provided an update following the receipt of minutes from its Regenerative Medicine and Advanced Therapy (RMAT)/Type B meeting with the U.S. Food and Drug Administration (FDA) held in December 2018, regarding the company's lead gene therapy candidate, AT132, for the treatment of X-linked Myotubular Myopathy (XLMTM). Following the meeting, the company is proceeding with its previously announced plan to enroll an additional 3-5 patients in Cohort 2 (3x1014 vector genomes per kilogram dose level) of ASPIRO, the Phase 1/2 study of AT132. Optimal dose selection is expected to occur in the second quarter of 2019, after the evaluation of the six-month biopsy results from the first three patients dosed in Cohort 2. Subsequent to the determination of the optimal dose, the company plans to provide an updated data package to FDA to facilitate final agreement on the path to BLA submission. The company also received preliminary feedback on its CMC characterization and validation plans and will submit the requested information to the Investigational New Drug (IND) application on a continuing basis.