Efficacy of idebenone on respiratory function in patients with Duchenne muscular dystrophy not using glucocorticoids (DELOS): a double-blind randomised placebo-controlled phase 3 trial

Lancet. 2015 May 2;385(9979):1748-1757. doi: 10.1016/S0140-6736(15)60025-3. Epub 2015 Apr 20.


Background: Cardiorespiratory failure is the leading cause of death in Duchenne muscular dystrophy. Based on preclinical and phase 2 evidence, we assessed the efficacy and safety of idebenone in young patients with Duchenne muscular dystrophy who were not taking concomitant glucocorticoids.

Methods: In a multicentre phase 3 trial in Belgium, Germany, the Netherlands, Switzerland, France, Sweden, Austria, Italy, Spain, and the USA, patients (age 10-18 years old) with Duchenne muscular dystrophy were randomly assigned in a one-to-one ratio with a central interactive web response system with a permuted block design with four patients per block to receive idebenone (300 mg three times a day) or matching placebo orally for 52 weeks. Study personnel and patients were masked to treatment assignment. The primary endpoint was change in peak expiratory flow (PEF) as percentage predicted (PEF%p) from baseline to week 52, measured with spirometry. Analysis was by intention to treat (ITT) and a modified ITT (mITT), which was prospectively defined to exclude patients with at least 20% difference in the yearly change in PEF%p, measured with hospital-based and weekly home-based spirometry. This study is registered with ClinicalTrials.gov, number NCT01027884.

Findings: 31 patients in the idebenone group and 33 in the placebo group comprised the ITT population, and 30 and 27 comprised the mITT population. Idebenone significantly attenuated the fall in PEF%p from baseline to week 52 in the mITT (-3·05%p [95% CI -7·08 to 0·97], p=0·134, vs placebo -9·01%p [-13·18 to -4·84], p=0·0001; difference 5·96%p [0·16 to 11·76], p=0·044) and ITT populations (-2·57%p [-6·68 to 1·54], p=0·215, vs -8·84%p [-12·73 to -4·95], p<0·0001; difference 6·27%p [0·61 to 11·93], p=0·031). Idebenone also had a significant effect on PEF (L/min), weekly home-based PEF, FVC, and FEV1. The effect of idebenone on respiratory function outcomes was similar between patients with previous corticosteroid use and steroid-naive patients. Treatment with idebenone was safe and well tolerated with adverse event rates were similar in both groups. Nasopharyngitis and headache were the most common adverse events (idebenone, eight [25%] and six [19%] of 32 patients; placebo, nine [26%] and seven [21%] of 34 patients). Transient and mild diarrhoea was more common in the idebenone group than in the placebo group (eight [25%] vs four [12%] patients).

Interpretation: Idebenone reduced the loss of respiratory function and represents a new treatment option for patients with Duchenne muscular dystrophy.

Funding: Santhera Pharmaceuticals.

Publication types

  • Clinical Trial, Phase III
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Antioxidants / therapeutic use*
  • Child
  • Double-Blind Method
  • Humans
  • Male
  • Muscular Dystrophy, Duchenne / complications
  • Muscular Dystrophy, Duchenne / drug therapy*
  • Muscular Dystrophy, Duchenne / physiopathology
  • Peak Expiratory Flow Rate
  • Respiration Disorders / drug therapy*
  • Respiration Disorders / etiology
  • Respiration Disorders / physiopathology
  • Respiratory Function Tests
  • Respiratory Muscles / physiopathology
  • Treatment Outcome
  • Ubiquinone / analogs & derivatives*
  • Ubiquinone / therapeutic use


  • Antioxidants
  • Ubiquinone
  • idebenone

Associated data

  • ClinicalTrials.gov/NCT01027884