NCT04655508 - Efficacy of Fluticasone Propionate Associated With Salmeterol Using Inhalation Chamber Versus Placebo to Improve the Respiratory Function in Children Over Six Years of Age Who Underwent Allogeneic Hematopoietic Stem Cell Transplantation With a Decline of FEV1 ≥10% From Pre Transplantation | Crick | Crick