Long-Term Expression of HMI-203: Investigational Gene Therapy Candidate for Mucopolysaccharidosis Type II (MPS II), or Hunter Syndrome Long-Term Expression of HMI-203: Investigational Gene Therapy Candidate for Mucopolysaccharidosis Type II (MPS II), or Hunter Syndrome Smith L, Patel K, Gingras J, et al. ASGCT 2021.