A Study Assessing KB407 for the Treatment of Cystic Fibrosis

KB407-02 A Phase 1 Study of Inhaled KB407, a Replication-Defective, Non-Integrating Vector Expressing Human Cystic Fibrosis Transmembrane Conductance Regulator, for the Treatment of Cystic Fibrosis

A Study Assessing KB407 for the Treatment of Cystic Fibrosis (NCT05504837) is a Phase 1 interventional studying Cystic Fibrosis, sponsored by Krystal Biotech, Inc.. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

This study will evaluate safety and tolerability of ascending doses of nebulized KB407 in adults with cystic fibrosis.

What Stage of Research Is This?

Phase 1 trials test a new treatment for the first time in humans, focusing on safety, dosing, and how the body processes the drug. For Cystic Fibrosis, a Phase 1 study typically enrolls a small number of participants — often healthy volunteers or patients who have exhausted standard treatment options. Phase 1 results determine whether a treatment moves into larger Phase 2 efficacy studies.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

With a target enrollment of 20 participants, this is a small study — typical of early-phase research, rare-disease trials, or pilot studies designed to generate preliminary signal before a larger study is launched.

Who May Be Eligible (Plain English)

Who May Qualify: 1. The subject must have read, understood, and signed an Institutional Review Board/Ethics Committee (IRB/IEC) approved willing to sign a consent form Form and must be able to and willing to follow study procedures and instructions 2. Subjects aged 18 years or older at the time of willing to sign a consent form 3. A confirmed diagnosis of CF as defined by clinical signs and symptoms of CF and at least one of the following: - A historical sweat chloride value \>60 mmol/L - Two copies of a disease causing mutation in the CFTR gene 4. Clinically stable in the opinion of the Investigator 5. Percent predicted FEV1 ≥40% and ≤90% of the predicted normal for age, gender, and height at Screening 6. Resting oxygen saturation ≥92% on room air at Screening Who Should NOT Join This Trial: 1. Initiation of any new chronic therapy (eg, CFTR modulator, hypertonic saline, inhaled antibiotic) or any change in chronic therapy (excluding pancreatic enzyme replacement therapy) within 28 days prior to the first dose 2. Hospitalization, sinopulmonary infection, CF exacerbation, or other clinically significant infection or illness 14 days prior to the first dose that, in the opinion of the Investigator, may confound study results 3. Treatment for Mycobacterium abscessus within 3 months prior to the first dose or more than two pulmonary exacerbations with a history of Burkholderia cenocepacia infection within 6 months prior to the first dose 4. Participation in another clinical study or treatment with an investigational agent 30 days or 5 half-lives, whichever is longer, prior to the first dose 5. History of or listed for solid organ transplantation ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: 1. The subject must have read, understood, and signed an Institutional Review Board/Ethics Committee (IRB/IEC) approved Informed Consent Form and must be able to and willing to follow study procedures and instructions 2. Subjects aged 18 years or older at the time of Informed Consent 3. A confirmed diagnosis of CF as defined by clinical signs and symptoms of CF and at least one of the following: * A historical sweat chloride value \>60 mmol/L * Two copies of a disease causing mutation in the CFTR gene 4. Clinically stable in the opinion of the Investigator 5. Percent predicted FEV1 ≥40% and ≤90% of the predicted normal for age, gender, and height at Screening 6. Resting oxygen saturation ≥92% on room air at Screening Exclusion Criteria: 1. Initiation of any new chronic therapy (eg, CFTR modulator, hypertonic saline, inhaled antibiotic) or any change in chronic therapy (excluding pancreatic enzyme replacement therapy) within 28 days prior to the first dose 2. Hospitalization, sinopulmonary infection, CF exacerbation, or other clinically significant infection or illness 14 days prior to the first dose that, in the opinion of the Investigator, may confound study results 3. Treatment for Mycobacterium abscessus within 3 months prior to the first dose or more than two pulmonary exacerbations with a history of Burkholderia cenocepacia infection within 6 months prior to the first dose 4. Participation in another clinical study or treatment with an investigational agent 30 days or 5 half-lives, whichever is longer, prior to the first dose 5. History of or listed for solid organ transplantation 6. Any condition (including a history or current evidence of substance abuse or dependence, uncontrolled asthma, or is considered to be immunocompromised) that, in the opinion of the Investigator, would impact a subject's ability to complete all study-related procedures and/or poses an additional risk to the assessment of safety of KB407 7. An active oral herpes infection 30 days prior to the first dose 8. Women who are pregnant or nursing 9. Subject who is unwilling to comply with contraception requirements per protocol 10. Clinically significant abnormalities of hematology or chemistry testing at Screening that the Investigator believes may interfere with the assessment of safety and/or efficacy of the study treatment 11. Subject has a known hypersensitivity to inhaled glycerol 12. Subject is known to be noncompliant or is unlikely to comply with the requirements of the study protocol in the opinion of the Investigator 13. Bronchoscopy participants only: Unable to tolerate bronchoscopy procedure and airway sampling, in the opinion of the Investigator 14. Cohort 4 participants only: Subjects who are ineligible for, do not tolerate, or do not benefit from modulator therapy

Treatments Being Tested

BIOLOGICAL

KB407 (Nebulization)

Nebulized solution of KB407, a replication-defective HSV-1 expressing full length human CFTR

Locations (6)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

University of Florida, Gainesville

Gainesville, Florida, United States

St. Lukes CF Center of Idaho

Boise, Idaho, United States

The Cystic Fibrosis Institute

Northfield, Illinois, United States

New York Medical College/ Boston Children's Health Physicians

Hawthorne, New York, United States

Northwell Health Physicians

New York, New York, United States

Atrium Health Wake Forest Baptist Medical Center

Winston-Salem, North Carolina, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT05504837), the sponsor (Krystal Biotech, Inc.), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT05504837 clinical trial studying?

This study will evaluate safety and tolerability of ascending doses of nebulized KB407 in adults with cystic fibrosis. The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT05504837?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT05504837?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT05504837. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT05504837. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.