Current Environment:


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.


Cystic Fibrosis

Recruitment Status


Detailed Description

This clinical trial information was submitted voluntarily under the applicable law and, therefore, certain submission deadlines may not apply. (That is, clinical trial information for this applicable clinical trial was submitted under section 402(j)(4) (A) of the Public Health Service Act and 42 CFR 11.60 and is not subject to the deadlines established by sections 402(j)(2) and (3) of the Public Health Service Act or 42 CFR 11.24 and 11.44.).

Eligibility Criteria

Key Inclusion Criteria:

Body mass index is less than (<) 30.0 kilograms per meter square (kg/m^2)
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 (<) 94% at screening

Other protocol defined Inclusion/Exclusion criteria may apply.


Intervention Type

Intervention Name


VX-522 mRNA therapy


Phase 1



Min Age

18 Years

Max Age

65 Years

Download Date

November 1, 2023

Principal Investigator

Ahmet Uluer

This field has been modified from to show a contact specific to Boston Children's.

Primary Contact Information

Robert Fowler

This field has been modified from to show a contact specific to Boston Children's.

For more information on this trial, visit


For more information and to contact the study team:

A Phase 1 Study of VX-522 in Participants With Cystic Fibrosis (CF) NCT05668741 Robert Fowler