Moving Forward after Two Deaths in a Gene Therapy Trial of Myotubular Myopathy
1
The sponsor of this clinical study, Audentes Therapeutics (which was acquired by Japan’s Astellas Pharma in 2019), had generated impressive efficacy studies in a canine model of MTM
2 and conducted non-primate (NHP) safety studies before advancing into the clinic.
3 The initial cohort of six pediatric MTM patients dosed at 1×10
14 genome copies (GC)/kg also showed encouraging results. However, all three patients administered a three-fold higher dose (i.e. 3×10
14 GC/kg) experienced severe hepatotoxicity, which has proven lethal in two of these subjects.
The success of the adeno-associated virus (AAV)-based product Zolgensma, approved in 2019 for the treatment of infants with spinal muscular atrophy (SMA) type 1, supported the safety and efficacy of infusing up to 1×10