A Phase 2 Study Evaluating Safety and Tolerability of RCT2100 (CFTR mRNA) in Healthy Participants and in Participants With CF

January 14, 2026 updated by: ReCode Therapeutics

A Phase 1/2, Multicenter Study Evaluating the Safety, Tolerability, and Biodistribution of RCT2100 With Single-Ascending Doses in Healthy Participants and Multiple-Ascending Doses and Proof-of-Concept in Participants With Cystic Fibrosis

This is the first-in-human study with RCT2100 and is designed to provide safety and tolerability data for future clinical studies.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is a multi-part study to assess the safety, tolerability, and biodistribution of a single ascending dose of inhaled RCT2100 administered via nebulizer to healthy participants (Part 1), the safety and tolerability of multiple-ascending doses of inhaled RCT2100 administered to participants with CF (Part 2), and the safety and tolerability of RCT2100 co-administered with ivacaftor in participants with CF (Part 3).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
192

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • France
      • Montpellier, France
        • Recruiting
        • Centre Hospitalier Régional Universitaire de Montpellier - Hôpital Arnaud de Villeneuve
      • Paris, France
        • Recruiting
        • Hopital Necker Enfants Malades
  • Netherlands
      • Utrecht, Netherlands
        • Recruiting
        • UMC Utrecht
  • New Zealand
      • Auckland, New Zealand
        • Completed
        • New Zealand Clinical Research (Part 1 Only)
  • United Kingdom
      • Birmingham, United Kingdom
        • Recruiting
        • University Hospitals Birmingham
      • Cambridge, United Kingdom
        • Recruiting
        • Royal Papworth Hospital
      • Leeds, United Kingdom
        • Recruiting
        • Leeds Teaching Hospitals
      • London, United Kingdom
        • Recruiting
        • King's College Hospital
      • Nottingham, United Kingdom
        • Recruiting
        • Nottingham University Hospitals
      • Southampton, United Kingdom
        • Recruiting
        • University Hospital Southampton
  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35294
        • Recruiting
        • The University of Alabama at Birmingham
    • Arizona
      • Tucson, Arizona, United States, 85719
        • Recruiting
        • University of Arizona
    • California
      • Palo Alto, California, United States, 94304
        • Recruiting
        • Stanford University
      • San Diego, California, United States, 92037
        • Recruiting
        • UCSD
    • Colorado
      • Denver, Colorado, United States, 80206
        • Recruiting
        • National Jewish Health
    • Georgia
      • Atlanta, Georgia, United States, 30322
        • Recruiting
        • Emory University
    • Massachusetts
      • Boston, Massachusetts, United States, 02215
        • Recruiting
        • Boston Children's Hospital
    • New York
      • Valhalla, New York, United States, 10595
        • Recruiting
        • New York Medical College
    • North Carolina
      • Chapel Hill, North Carolina, United States, 27599
        • Recruiting
        • The University of North Carolina at Chapel Hill
    • Oregon
      • Portland, Oregon, United States, 97239
        • Recruiting
        • Oregon Health & Science University
    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15213
        • Recruiting
        • University of Pittsburgh
    • Texas
      • Dallas, Texas, United States, 75390
        • Recruiting
        • UT Southwestern Medical Center
    • Washington
      • Seattle, Washington, United States, 98195
        • Recruiting
        • University of Washington

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Part 1 Major Inclusion Criteria:

  • Healthy, adult, male or female, 18-55 years of age, inclusive, at screening.
  • Body weight greater than or equal to 50 kg and body mass index (BMI) between 16-32 kg/m2, inclusive
  • The participant has a forced expiratory volume in one second (FEV1) of at least 80% predicted
  • The participant is considered by the investigator to be in good general health as determined by medical history, clinical laboratory test results, vital sign measurements, 12-lead ECG results, and physical examination findings at screening.
  • Understands the study procedures in the informed consent form (ICF), and is willing and able to comply with the protocol.

Part 1 Major Exclusion Criteria:

  • History or presence of clinically significant medical, surgical, clinical laboratory, or psychiatric condition or disease.
  • The participant has supine blood pressure (BP) >150 mm Hg (systolic) or >90 mm Hg (diastolic), following at least 5 minutes of supine rest.
  • The participant has abnormal clinical laboratory tests at screening, as assessed by the study-specific laboratory.
  • The participant is a smoker or has used nicotine or nicotine-containing products 6 weeks before the first dose of study drug. Former smokers with greater than 10 pack years of smoking history are excluded.

Part 2 Major Inclusion Criteria:

  • Confirmed diagnosis of CF
  • Forced expiratory volume in 1 second ≥50% and ≤100% of predicted mean value for age, sex, and height
  • a) Not eligible for CFTR modulators based on having mutations of CFTR gene on both alleles that are not responsive to CFTR modulator therapy OR
  • b) Eligible for CFTR modulators (based on local prescribing information) but not using CFTR modulators due to intolerance or contraindications

Part 2 Major Exclusion Criteria:

  • Hepatic cirrhosis with portal hypertension, moderate hepatic impairment (Child Pugh Score 7 to 9), or severe hepatic impairment (Child Pugh Score 10 to 15)
  • An acute upper or lower respiratory infection, pulmonary exacerbation, or changes in therapy (including antibiotics) for sinopulmonary disease within 4 weeks before the first dose of study drug
  • Lung infection with organisms associated with a more rapid decline in pulmonary status
  • Arterial oxygen saturation on room air less than 94% at screening
  • Treatment with a CFTR modulator (Kalydeco, Trikafta, Symdeko, Orkambi, or Alyftrek) within 12 weeks of Screening

Other protocol defined Inclusion/Exclusion criteria may apply.

Part 3 Major Inclusion Criteria:

  • Confirmed diagnosis of CF
  • Forced expiratory volume in 1 second ≥50% and ≤100% of predicted mean value for age, sex, and height
  • a) Not eligible for CFTR modulators based on having mutations of CFTR gene on both alleles that are not responsive to CFTR modulator therapy OR
  • b) Eligible for dual or triple CFTR modulators (based on local prescribing information) but not using CFTR modulators due to intolerance or contraindications

Part 3 Major Exclusion Criteria:

  • Hepatic cirrhosis with portal hypertension, moderate hepatic impairment (Child Pugh Score 7 to 9), or severe hepatic impairment (Child Pugh Score 10 to 15)
  • An acute upper or lower respiratory infection, pulmonary exacerbation, or changes in therapy (including antibiotics) for sinopulmonary disease within 4 weeks before the first dose of study drug
  • Lung infection with organisms associated with a more rapid decline in pulmonary status
  • Arterial oxygen saturation on room air less than 94% at screening
  • Treatment with a CFTR modulator (Kalydeco, Trikafta, Symdeko, Orkambi, or Alyftrek) within 12 weeks of Screening

Other protocol defined Inclusion/Exclusion criteria may apply.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: RCT2100 (Part 1)
RCT2100 single dose
Drug: RCT2100
RCT2100 supplied as varying dose strengths administered via oral inhalation using nebulizer
Drug: RCT2100
RCT2100 supplied as varying dose strengths administered via oral inhalation using nebulizer for 4 weeks
Drug: RCT2100
RCT2100 supplied at a single dose strength administered via oral inhalation using nebulizer for 12 weeks
Drug: RCT2100
RCT2100 supplied at varying dose strengths. Co- administered via oral inhalation using nebulizer for 4 weeks with ivacaftor after initial 2 weeks of ivacaftor dosing run in period
Placebo Comparator: Placebo (Part 1)
Placebo single dose
Other: Placebo
Placebo of similar volumes to experimental dose strengths administered via oral inhalation using nebulizer
Experimental: RCT2100 (Part 2) 4 week
RCT2100 multiple dose
Drug: RCT2100
RCT2100 supplied as varying dose strengths administered via oral inhalation using nebulizer
Drug: RCT2100
RCT2100 supplied as varying dose strengths administered via oral inhalation using nebulizer for 4 weeks
Drug: RCT2100
RCT2100 supplied at a single dose strength administered via oral inhalation using nebulizer for 12 weeks
Drug: RCT2100
RCT2100 supplied at varying dose strengths. Co- administered via oral inhalation using nebulizer for 4 weeks with ivacaftor after initial 2 weeks of ivacaftor dosing run in period
Experimental: RCT2100 (Part 2) 12 week
RCT2100 multiple dose
Drug: RCT2100
RCT2100 supplied as varying dose strengths administered via oral inhalation using nebulizer
Drug: RCT2100
RCT2100 supplied as varying dose strengths administered via oral inhalation using nebulizer for 4 weeks
Drug: RCT2100
RCT2100 supplied at a single dose strength administered via oral inhalation using nebulizer for 12 weeks
Drug: RCT2100
RCT2100 supplied at varying dose strengths. Co- administered via oral inhalation using nebulizer for 4 weeks with ivacaftor after initial 2 weeks of ivacaftor dosing run in period
Experimental: Experimental: RCT2100 (Part 3) 6 week
RCT2100 multiple dose
Drug: RCT2100
RCT2100 supplied as varying dose strengths administered via oral inhalation using nebulizer
Drug: RCT2100
RCT2100 supplied as varying dose strengths administered via oral inhalation using nebulizer for 4 weeks
Drug: RCT2100
RCT2100 supplied at a single dose strength administered via oral inhalation using nebulizer for 12 weeks
Drug: RCT2100
RCT2100 supplied at varying dose strengths. Co- administered via oral inhalation using nebulizer for 4 weeks with ivacaftor after initial 2 weeks of ivacaftor dosing run in period
Drug: Ivacaftor
ivacaftor administered orally for 6 weeks

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Part 1: The number of participants with Adverse Events (AEs) and Serious Adverse Events (SAEs).
Time Frame: From Baseline Through Day 29
Safety and tolerability as assessed by number of participants with Adverse Events (AEs) and Serious Adverse Events (SAEs)
From Baseline Through Day 29
Part 2: The number of participants with CF with AEs and SAEs.
Time Frame: From Day 1 through Safety Follow-up, Week 24
Safety and tolerability of multiple-ascending doses of inhaled RCT2100 administered to participants with CF
From Day 1 through Safety Follow-up, Week 24
Part 3: The number of participants with CF with AEs and SAEs.
Time Frame: From Day 1 through Safety Follow-up, Week 24
To assess the safety and tolerability of RCT2100 co-administered with ivacaftor in participants with CF.
From Day 1 through Safety Follow-up, Week 24

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
ReCode Therapeutics

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: John Matthews, MBBS, MCRP, PhD, ReCode Therapeutics, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 1, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 30, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 23, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 23, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 1, 2024

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 16, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 14, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • RCT2100-101
  • 2024-512169-15 (EudraCT Number)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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