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ClinicalTrials.gov 49 recruiting now early-phase tilt #64 of 28,707 conditions

Cystic Fibrosis: early-phase trial registry

49 of 170 indexed Cystic Fibrosis trials are currently recruiting, with more weight in Phase 1-2.

Corpus placement: #64 of 28,707 conditions by registered trial count.

170 US clinical trials · 49 currently recruiting · #64 of 28,707 conditions by registered trial count

Cystic Fibrosis: 170 US clinical trials tracked, 49 recruiting.

Cystic Fibrosis is the subject of 170 registered US clinical trials on ClinicalTrials.gov, 49 of them currently open to new participants. 34 are in Phase 3-4 (later-stage) and 61 in Phase 1-2 (earlier-stage). The most active sponsor is Vertex Pharmaceuticals Incorporated, running 20 of these trials.

Enrollment posture brief

Registry condition cystic-fibrosis

OPEN 49 | RECR 29% | LATE 34 | EARLY 61 | RANK #64 | SPON 20

Nearest open-share peer: Prostatic Neoplasms (29% recruiting · 66 trials)

Malignant Solid Neoplasm53.1%Epilepsy47.6%Traumatic Brain Injury43.6%Cystic Fibrosis (this)29%Bipolar Disorder22.7%
Open-enrollment share among volume-matched conditions near Cystic Fibrosis

Cystic Fibrosis lists 49 open slots (29% of 170 indexed trials). Peers are matched on registered volume, not therapeutic-area browse lists. How peer matching works →

Key findings

What ClinicalTrials.gov does not surface for Cystic Fibrosis on its own pages , computed from the registry mirror as of 2026-08-08. Each line carries its own denominator so it can be quoted as it stands.

  1. Cystic Fibrosis is recruiting below its size-band peers.

    49 of 170 indexed trials (28.8%) are open to enrollment, against a 37.1% average across 139 conditions with 100+ trials. The peer set uses the same ClinicalTrials.gov-derived counts as this page.

  2. Sponsorship of Cystic Fibrosis trials is spread across many organizations.

    Vertex Pharmaceuticals Incorporated accounts for 20 of 170 trials (11.8%). 84 distinct sponsors appear on at least one study for this condition label.

  3. Most Cystic Fibrosis trials plan to enrol fewer than 100 people.

    Median target enrolment is 59 among the 170 trials that report a genuine target (sentinel values excluded). 107 of those (62.9%) plan for fewer than 100 participants.

  4. Cystic Fibrosis research is mostly interventional.

    121 interventional and 49 observational studies make up this index (71.2% interventional). Study type is sponsor-reported on ClinicalTrials.gov.

Phase 134Phase 227Phase 319Phase 415

Open and recent trials

170 total, page 2 of 4

ACTIVE NOT RECRUITING Phase 3 822 participants

A Study Evaluating the Long-term Safety and Efficacy of VX-121 Combination Therapy

Vertex Pharmaceuticals Incorporated

NCT05444257

ACTIVE NOT RECRUITING 600 participants

Gene Modifiers of Cystic Fibrosis Lung Disease

University of North Carolina, Chapel Hill

NCT00037765

ACTIVE NOT RECRUITING 350 participants

Colorectal Cancer Screening in Cystic Fibrosis

University of Washington, the Collaborative Health Studies Coordinating Center

NCT05362344

ACTIVE NOT RECRUITING 300 participants

Strength and Muscle Related Outcomes for Nutrition and Lung Function in CF

Jaeb Center for Health Research

NCT05639556

ACTIVE NOT RECRUITING 285 participants

Prospective Study of Pregnancy in Women With Cystic Fibrosis

Amalia Magaret

NCT04828382

ACTIVE NOT RECRUITING 180 participants

The PROMISE Pediatric Study 6 to 11 Years Old

Nicole Hamblett

NCT04613128

ACTIVE NOT RECRUITING 154 participants

Genetic Modifiers of Cystic Fibrosis (CF) Liver Disease

University of North Carolina, Chapel Hill

NCT00804583

ACTIVE NOT RECRUITING NA 132 participants

Lung Transplant READY CF 2: A Multi-site RCT

University of Washington

NCT06030206

ACTIVE NOT RECRUITING 100 participants

Host and Bacterial Mechanisms During Cystic Fibrosis Pulmonary Exacerbations

National Jewish Health

NCT04354038

ACTIVE NOT RECRUITING 86 participants

Pulmonary Vascular Disease in CF

Children's Hospital Medical Center, Cincinnati

NCT04549077

ACTIVE NOT RECRUITING Phase 4 64 participants

Hyperpolarized Imaging for New Treatments

Children's Hospital Medical Center, Cincinnati

NCT04259970

ACTIVE NOT RECRUITING 63 participants

CFTR Modulator Effects on Bone and Muscle in Adults With Cystic Fibrosis

Indiana University

NCT04206436

ACTIVE NOT RECRUITING 60 participants

High Resolution Micro OCT Imaging

University of Alabama at Birmingham

NCT03256773

ACTIVE NOT RECRUITING 38 participants

Monitoring Response to Orkambi in Cystic Fibrosis Lung Disease by Inhaled Xenon MRI

Children's Hospital Medical Center, Cincinnati

NCT02848560

ACTIVE NOT RECRUITING Phase 4 26 participants

Non-contrast Lung Perfusion Mapping Applied for New Insights in Cystic Fibrosis

Children's Hospital Medical Center, Cincinnati

NCT04467957

ACTIVE NOT RECRUITING Phase 1 18 participants

Effect of Vanzacaftor/Tezacaftor/Deutivacaftor (VNZ/TEZ/D-IVA) on the PK of Rosuvastatin in Healthy Participants

Vertex Pharmaceuticals Incorporated

NCT07349394

ACTIVE NOT RECRUITING Early Phase 1 16 participants

Effect of Losartan in Cystic Fibrosis (CF)-NIH Grant #133240

University of Kansas Medical Center

NCT03435939

ACTIVE NOT RECRUITING NA 13 participants

Mechanisms for Vascular Dysfunction and Exercise Tolerance in CF

Augusta University

NCT02690064

ACTIVE NOT RECRUITING NA 10 participants

Implementation of a Clinical Tool to Improve Waitlist Mortality in Patients With Cystic Fibrosis

The Cleveland Clinic

NCT04687475

ACTIVE NOT RECRUITING Phase 2 8 participants

SGLT2 Inhibitor Therapy in Cystic Fibrosis-related Diabetes

University of Minnesota

NCT06149793

COMPLETED 860 participants

HERO-2: Home-Reported Outcomes With CFTR Modulator Therapy

Indiana University

NCT04798014

COMPLETED Phase 3 517 participants

Safety of Tobramycin Inhalation Powder (TIP) vs Tobramycin Solution for Inhalation in Patients With Cystic Fibrosis

Novartis Pharmaceuticals

NCT00388505

COMPLETED Phase 2 510 participants

Safety and Efficacy of 12-wk Treatment With Two Doses of Tiotropium Respimat in Cystic Fibrosis

Boehringer Ingelheim

NCT00737100

COMPLETED 452 participants

A Two-Part Multicenter Prospective Longitudinal Study of CFTR-dependent Disease Profiling in Cystic Fibrosis (PROSPECT)

University of Alabama at Birmingham

NCT02477319

COMPLETED Phase 3 330 participants

MP-376 (Aeroquin™, Levofloxacin for Inhalation) in Patients With Cystic Fibrosis

Amgen

NCT01180634

COMPLETED Phase 3 318 participants

Long Term Administration of Inhaled Mannitol in Cystic Fibrosis

Syntara

NCT00630812

COMPLETED Phase 2 312 participants

Study of VX-809 Alone and in Combination With VX-770 in Cystic Fibrosis (CF) Patients Homozygous or Heterozygous for the F508del-CFTR Mutation

Vertex Pharmaceuticals Incorporated

NCT01225211

COMPLETED Phase 3 279 participants

Study of Ataluren in Nonsense Mutation Cystic Fibrosis (ACT CF)

PTC Therapeutics

NCT02139306

COMPLETED NA 267 participants

Early Intervention in Cystic Fibrosis Exacerbation

Johns Hopkins University

NCT01104402

COMPLETED Phase 3 248 participants

A Phase 3 Study to Evaluate the Efficacy and Safety of Ivacaftor and VX-661 in Combination With Ivacaftor in Subjects Aged 12 Years and Older With Cystic Fibrosis, Heterozygous for the F508del-cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Mutation

Vertex Pharmaceuticals Incorporated

NCT02392234

COMPLETED Phase 3 238 participants

Study of Ataluren (PTC124™) in Cystic Fibrosis

PTC Therapeutics

NCT00803205

COMPLETED NA 222 participants

Peer i-Coaching for Activated Self-Management Optimization in Adolescents and Young Adults With Chronic Conditions

Duke University

NCT03938324

COMPLETED Phase 3 221 participants

OPTIMIZing Treatment for Early Pseudomonas Aeruginosa Infection in Cystic Fibrosis

Bonnie Ramsey

NCT02054156

COMPLETED Phase 3 214 participants

Open-Label Phase III Long-Term Safety Trial of Liprotamase

Anthera Pharmaceuticals

NCT00449904

COMPLETED Phase 1 171 participants

Study Assessing the Safety, Tolerability, Pharmacokinetics, Food Effect, and Drug-Drug Interactions of PTI-801 in Healthy Volunteers, and Safety, Tolerability, and Pharmacokinetics of PTI-801 in Subjects With Cystic Fibrosis

Proteostasis Therapeutics

NCT03140527

COMPLETED Phase 3 163 participants

Liprotamase Efficacy Trial in Patients With Cystic Fibrosis-Related Exocrine Pancreatic Insufficiency

Anthera Pharmaceuticals

NCT00449878

COMPLETED NA 150 participants

Saline Hypertonic in Preschoolers

University of Washington, the Collaborative Health Studies Coordinating Center

NCT02378467

COMPLETED 150 participants

Utility of CD64 and TLR2 Assays to Diagnose Acute Pulmonary Exacerbations in Cystic Fibrosis

National Jewish Health

NCT04397809

COMPLETED Phase 2 138 participants

Study of Cavosonstat (N91115) in Patients With CF Homozygous for the F508del-CFTR Mutation

Nivalis Therapeutics

NCT02589236

COMPLETED Phase 3 125 participants

Rollover Study of Ivacaftor in Subjects With Cystic Fibrosis and a Non G551D CFTR Mutation

Vertex Pharmaceuticals Incorporated

NCT01707290

COMPLETED Phase 2 124 participants

A Study Evaluating the Safety and Efficacy of VX-659 Combination Therapy in Subjects With Cystic Fibrosis

Vertex Pharmaceuticals Incorporated

NCT03224351

COMPLETED 123 participants

Cystic Fibrosis Foundation (CFF) Biomarkers of Exacerbation

University of Colorado, Denver

NCT00788359

COMPLETED 120 participants

G551D Observational Study- Expanded to Additional Genotypes and Extended for Long Therm Follow up (GOAL-e2)

Steven M Rowe

NCT01521338

COMPLETED 112 participants

T Cell Memory Fuels the Innate Response in Chronic CF Lung Disease

National Jewish Health

NCT04397861

COMPLETED Phase 2 110 participants

Study of LYM-X-SORB™ to Improve Fatty Acid and Choline Status in Children With CF and PI

Avanti Polar Lipids

NCT00406536

COMPLETED Phase 3 108 participants

Diabetes Therapy to Improve BMI and Lung Function in CF

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

NCT00072904

COMPLETED NA 105 participants

Feasibility of a Mobile Medication Plan Application in CF Patient Care

Boston Children's Hospital

NCT03637504

COMPLETED Phase 2 105 participants

Aztreonam for Inhalation (AI) in Patients With Cystic Fibrosis & P. Aeruginosa Infection

Gilead Sciences

NCT01055847

COMPLETED Phase 3 100 participants

Cystic Fibrosis - Insulin Deficiency, Early Action

Sydney Children's Hospitals Network

NCT01100892

COMPLETED 95 participants

An Ocular Safety Study of Ivacaftor-Treated Pediatric Patients 11 Years of Age or Younger With Cystic Fibrosis

Vertex Pharmaceuticals Incorporated

NCT01863238

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Phase Distribution

PhaseTrial count
Phase 1 34
Phase 2 27
Phase 3 19
Phase 4 15

Named interventions

Most-linked intervention names on Cystic Fibrosis records (sponsor-reported on ClinicalTrials.gov). Counts are trial links, not unique products.

Placebo Drug
17 trials
Ivacaftor Drug
6 trials
IVA Drug
5 trials
Placebo Other
5 trials
Lumacaftor Drug
3 trials
VX-121/TEZ/D-IVA Drug
3 trials
Liprotamase Drug
2 trials
TEZ/IVA Drug
2 trials

US sites by state

Facility locations filed on Cystic Fibrosis trials. A trial with sites in several states counts in each.

Colorado 55 trials
California 52 trials
Massachusetts 45 trials
Florida 45 trials
Pennsylvania 42 trials
Ohio 42 trials
Alabama 42 trials
Illinois 41 trials

Source: ClinicalTrials.gov, National Library of Medicine. Data is informational only.

What to do with this Cystic Fibrosis page

170 registered trials, 49 currently recruiting, is a starting point for a conversation, not a diagnosis or a recommendation.

Trial and recruiting counts reflect ClinicalTrials.gov registry status as of the data vintage above; individual trial eligibility and enrollment status can change.

Every figure on PlainTrial is rendered directly from the ClinicalTrials.gov registry, no number is typed in by an editor. This Cystic Fibrosis condition card totals 170 registered trials; most-linked intervention Placebo; top US site state Colorado. See our editorial standards & corrections policy, the methodology behind these numbers, the data changelog, or report a data error.