title: Local dystrophin restoration with antisense oligonucleotide PRO051.
abstract: BACKGROUND
  Duchenne's muscular dystrophy is associated with severe, progressive muscle weakness and typically leads to death between the ages of 20 and 35 years. By inducing specific exon skipping during messenger RNA (mRNA) splicing, antisense compounds were recently shown to correct the open reading frame of the DMD gene and thus to restore dystrophin expression in vitro and in animal models in vivo. We explored the safety, adverse-event profile, and local dystrophin-restoring effect of a single, intramuscular dose of an antisense oligonucleotide, PRO051, in patients with this disease.
  
  
  METHODS
  Four patients, who were selected on the basis of their mutational status, muscle condition, and positive exon-skipping response to PRO051 in vitro, received a dose of 0.8 mg of PRO051 injected into the tibialis anterior muscle. A biopsy was performed 28 days later. Safety measures, composition of mRNA, and dystrophin expression were assessed.
  
  
  RESULTS
  PRO051 injection was not associated with clinically apparent adverse events. Each patient showed specific skipping of exon 51 and sarcolemmal dystrophin in 64 to 97% of myofibers. The amount of dystrophin in total protein extracts ranged from 3 to 12% of that found in the control specimen and from 17 to 35% of that of the control specimen in the quantitative ratio of dystrophin to laminin alpha2.
  
  
  CONCLUSIONS
  Intramuscular injection of antisense oligonucleotide PRO051 induced dystrophin synthesis in four patients with Duchenne's muscular dystrophy who had suitable mutations, suggesting that further studies might be feasible.
authors.affiliation: Department of Human and Clinical Genetics, Leiden University Medical Center, The Netherlands. j.vandeutekom@prosensa.nl
authors.forename: Judith C
authors.initials: JC
authors.lastname: van Deutekom
authors.forename: Anneke A
authors.initials: AA
authors.lastname: Janson
authors.forename: Ieke B
authors.initials: IB
authors.lastname: Ginjaar
authors.forename: Wendy S
authors.initials: WS
authors.lastname: Frankhuizen
authors.forename: Annemieke
authors.initials: A
authors.lastname: Aartsma-Rus
authors.forename: Mattie
authors.initials: M
authors.lastname: Bremmer-Bout
authors.forename: Johan T
authors.initials: JT
authors.lastname: den Dunnen
authors.forename: Klaas
authors.initials: K
authors.lastname: Koop
authors.forename: Anneke J
authors.initials: AJ
authors.lastname: van der Kooi
authors.forename: Nathalie M
authors.initials: NM
authors.lastname: Goemans
authors.forename: Sjef J
authors.initials: SJ
authors.lastname: de Kimpe
authors.forename: Peter F
authors.initials: PF
authors.lastname: Ekhart
authors.forename: Edna H
authors.initials: EH
authors.lastname: Venneker
authors.forename: Gerard J
authors.initials: GJ
authors.lastname: Platenburg
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Verschuuren
authors.forename: Gert-Jan B
authors.initials: GJ
authors.lastname: van Ommen
mesh_terms: D000293:Adolescent; D002648:Child; D015195:Drug Design; D016189:Dystrophin / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D005091:Exons; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D020388:Muscular Dystrophy, Duchenne / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D009841:Oligonucleotides / Q000009:adverse effects / Q000627:therapeutic use*; D016376:Oligonucleotides, Antisense / Q000009:adverse effects / Q000627:therapeutic use*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000032:analysis; D017384:Sequence Deletion; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: C484258:DMD protein, human; D016189:Dystrophin; D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense; C525434:PRO051; D012333:RNA, Messenger