NCT06999733 · Krystal Biotech, Inc.
A Study Assessing KB801 for the Treatment of Stage 2 or 3 Neurotrophic Keratitis
(EMERALD-1)
What this study is about
The Sponsor is developing KB801, a replication-defective, non-integrating herpes simplex virus type 1 (HSV-1)-derived vector engineered to deliver functional full-length human nerve growth factor (NGF) to the corneas of people with Stage 2 or 3 neurotrophic keratitis (NK) via topical application.
View original scientific description
The Sponsor is developing KB801, a replication-defective, non-integrating herpes simplex virus type 1 (HSV-1)-derived vector engineered to deliver functional full-length human nerve growth factor (NGF) to the corneas of people with Stage 2 or 3 neurotrophic keratitis (NK) via topical application. This is a Phase 1/2, multicenter, double-masked, placebo-controlled study to evaluate the safety, tolerability, and preliminary efficacy of KB801 in these subjects.
Interventions
BIOLOGICAL
KB801
Ophthalmic suspension of replication-defective, non-integrating herpes simplex virus type 1 (HSV-1)-based vector delivering functional, full-length human nerve growth factor (NGF)
DRUG
Placebo
Vehicle
Primary outcome measures
To evaluate safety and tolerability of KB801 based upon assessment of adverse events (frequency, severity, relatedness).
Time frame: 8 weeks
Number of subjects with treatment related adverse events as assessed by CTCAE v5.
To evaluate the effect of KB801 on complete healing of the Persistent Corneal Epithelial Defect (PCED) in subjects with Stage 2 or Stage 3 NK
Time frame: 8 weeks
Proportion of subjects receiving KB801 exhibiting complete PCED closure at Week 8 compared to those receiving placebo.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- The subject must have read, understood, and signed an Institutional Review Board (IRB) approved Informed Consent Form and must be willing and able to comply with study procedures and instructions. 2. Aged ≥ 18 years at the time of informed consent. 3. Diagnosis of Stage 2 or Stage 3 NK, as defined by the Mackie criteria. 4. Persistent corneal epithelial defect (PCED) of at least 2 weeks duration without clinical improvement during that time. PCED is defined as a focal loss of the cornea's outermost cell layer and can include involvement of the deeper stromal layers (i.e., corneal ulcer). 5. PCED at Screening 1 must have a minimum of 1 mm of any linear measurement of defect. 6. Decreased corneal sensitivity (≤ 4 cm using the Cochet-Bonnet esthesiometer \[CBE\]) within the area of the PCED and in at least one corneal quadrant outside of the area of the defect. 7. A negative pregnancy test at Screening 1 and Day 1 for women of child-bearing potential.
Where
- Irvine, California
- Pasadena, California
- Carmel, Indiana
- Alexandria, Minnesota
- Minnetonka, Minnesota
- Town and Country, Missouri
- Palisades Park, New Jersey
- West Fargo, North Dakota
- Pittsburgh, Pennsylvania
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Feb 27, 2026 · Source of record for eligibility and locations