Phase 1
A Phase 1 Study of VX-522 in Participants With Cystic Fibrosis (CF)

The purpose of this study is to evaluate the safety and tolerability of VX-522 in participants 18 years of age and older with cystic fibrosis and a cystic fibrosis transmembrane conductance regulator (CFTR) genotype not responsive to CFTR modulator therapy. Identifier

Eligibility criteria
18 Years - 65 Years
Key inclusion criteria
  • Body mass index is less than (
  • A total body weight greater than (>) 50 kg
  • Stable CF disease
  • CFTR gene mutations on both alleles that are not responsive to CFTR modulator therapy
  • o Example mutations include but are not limited to, mutations that do not produce CFTR protein (i.e., Class I): nonsense mutations (e.g., G542X, W1282X) and canonical splice mutations (e.g., 621+1G->T)
  • Forced expiratory volume in 1 second (FEV1) value, percent of predicted mean for age, sex, and height (equations of the Global Lung Function Initiative [GLI])18 ≥40%
Key exclusion criteria
  • History of uncontrolled asthma within a year prior to screening
  • History of solid organ or hematological transplantation
  • Hepatic cirrhosis with portal hypertension, moderate hepatic impairment (Child Pugh Score 7 to 9), or severe hepatic impairment (Child Pugh Score 10 to 15)
  • Arterial oxygen saturation on room air less than (
Other protocol defined Inclusion/Exclusion criteria may apply.
Trial details
Cystic Fibrosis
Study duration
February 2023 - January 2024
Study type
Drug : VX-522 mRNA therapy
Estimated enrollment

Interested in this trial?

Learn More

About clinical trials

Volunteers who participate in clinical trials help make new medicines a reality. Clinical trials are carefully designed research studies in humans that evaluate the safety and efficacy of an investigational medicine.

If you’re interested in participating in a Vertex clinical trial, we encourage you to speak with your health care provider first about what’s involved and your eligibility. 


  • Recruiting
    Baltimore - Early Phase Clinical Unit
    Baltimore Maryland 21225 United States
  • Recruiting
    Boston Children's Hospital
    Boston Massachusetts 02115 United States
  • Recruiting
    University of Minnesota
    Minneapolis Minnesota 55455 United States
  • Recruiting
    University of Cincinnati
    Cincinnati Ohio 45220 United States
  • Recruiting
    Nationwide Children's Hospital
    Columbus Ohio 43205 United States