Repeated Nebulisation of Non-Viral CFTR Gene Therapy in Patients With Cystic Fibrosis: A Randomised, Double-Blind, Placebo-Controlled, Phase 2b Trial

Lancet Respir Med. 2015 Sep;3(9):684-691. doi: 10.1016/S2213-2600(15)00245-3. Epub 2015 Jul 3.

Abstract

Background: Lung delivery of plasmid DNA encoding the CFTR gene complexed with a cationic liposome is a potential treatment option for patients with cystic fibrosis. We aimed to assess the efficacy of non-viral CFTR gene therapy in patients with cystic fibrosis.

Methods: We did this randomised, double-blind, placebo-controlled, phase 2b trial in two cystic fibrosis centres with patients recruited from 18 sites in the UK. Patients (aged ≥12 years) with a forced expiratory volume in 1 s (FEV1) of 50-90% predicted and any combination of CFTR mutations, were randomly assigned, via a computer-based randomisation system, to receive 5 mL of either nebulised pGM169/GL67A gene-liposome complex or 0.9% saline (placebo) every 28 days (plus or minus 5 days) for 1 year. Randomisation was stratified by % predicted FEV1 (<70 vs ≥70%), age (<18 vs ≥18 years), inclusion in the mechanistic substudy, and dosing site (London or Edinburgh). Participants and investigators were masked to treatment allocation. The primary endpoint was the relative change in % predicted FEV1. The primary analysis was per protocol. This trial is registered with ClinicalTrials.gov, number NCT01621867.

Findings: Between June 12, 2012, and June 24, 2013, we randomly assigned 140 patients to receive placebo (n=62) or pGM169/GL67A (n=78), of whom 116 (83%) patients comprised the per-protocol population. We noted a significant, albeit modest, treatment effect in the pGM169/GL67A group versus placebo at 12 months' follow-up (3.7%, 95% CI 0.1-7.3; p=0.046). This outcome was associated with a stabilisation of lung function in the pGM169/GL67A group compared with a decline in the placebo group. We recorded no significant difference in treatment-attributable adverse events between groups.

Interpretation: Monthly application of the pGM169/GL67A gene therapy formulation was associated with a significant, albeit modest, benefit in FEV1 compared with placebo at 1 year, indicating a stabilisation of lung function in the treatment group. Further improvements in efficacy and consistency of response to the current formulation are needed before gene therapy is suitable for clinical care; however, our findings should also encourage the rapid introduction of more potent gene transfer vectors into early phase trials.

Funding: Medical Research Council/National Institute for Health Research Efficacy and Mechanism Evaluation Programme.

Publication types

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

MeSH terms

  • Administration, Inhalation
  • Adolescent
  • Adult
  • Child
  • Cystic Fibrosis / drug therapy*
  • Cystic Fibrosis / genetics
  • Cystic Fibrosis / physiopathology
  • Cystic Fibrosis Transmembrane Conductance Regulator / administration & dosage*
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics*
  • Double-Blind Method
  • Female
  • Forced Expiratory Volume / drug effects
  • Genetic Therapy / methods*
  • Humans
  • Liposomes
  • Male
  • Mutation
  • Nebulizers and Vaporizers
  • Plasmids / administration & dosage*
  • United Kingdom
  • Young Adult

Substances

  • CFTR protein, human
  • Liposomes
  • Cystic Fibrosis Transmembrane Conductance Regulator

Associated data

  • ClinicalTrials.gov/NCT01621867