Neurotrophic KeratitisPhase 1/2EMERALD-1NCT06999733
A Study Comparing KB801 Verse Placebo in Patients With Stage 2 or 3 Neurotrophic Keratitis
A Phase 1/2 study testing KB801 in people with Neurotrophic Keratitis, run by Krystal Biotech, Inc. at 9 sites in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Neurotrophic Keratitis
- What is being tested?
- KB801
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 60 participants
- Where
- 9 sitesUnited States
- Study dates
- 7 Jul 2025to Dec 2027
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
- Aged ≥ 18 years at the time of informed consent.
- Diagnosis of Stage 2 or Stage 3 NK, as defined by the Mackie criteria.
- Persistent corneal epithelial defect (PCED) between Screening 1 and Screening 2 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).
- PCED at Screening 1 must have a minimum of 1 mm of any linear measurement of defect.
- A negative pregnancy test at Screening 1 and Day 1 for women of child-bearing potential.
Who cannot join
- An active ocular infection (bacterial, viral, fungal or protozoal) or active ocular inflammation not related to NK in the study eye as assessed by Investigator at Screening 1 or 2.
- Use of any prohibited therapies at Screening or anticipated need for topical treatments other than the investigational product or products allowed per protocol in the study eye from Screening through the study Treatment Period
- Sufficient washout of prohibited therapies must occur prior to meeting eligibility criteria.
- Anticipated use of therapeutic contact lenses or contact lens wear for refractive correction during the study Treatment Period in the study eye.
- Evidence of corneal ulceration involving the posterior third of the corneal stroma, corneal melting, descemetocele, impending or perforation in the study eye at the time of Screening 1 or 2.
- PCED at Screening 1 or 2 of > 8 mm maximum linear measurement in any eye.
Show all 15Show fewer
- The central 3 mm of corneas contain PCED bilaterally at Screening 1 or 2.
- Anticipated need for punctal occlusion of the study eye during the Treatment Period.
- Presence or history of any ocular or systemic disorder or condition that might hinder the efficacy of the study treatment or its evaluation, could possibly interfere with the interpretation of study results, or could be judged by the Investigator to be incompatible with the study visit schedule or conduct (e.g., progressive or degenerative corneal or retinal conditions, uveitis, optic neuritis, poorly controlled diabetes, autoimmune disease, systemic infection, neoplastic diseases).
- Participation in another clinical study or treatment with an investigational agent 30 days or 5 half-lives, whichever is longer, prior to Day 1 (participation in a non-interventional observational study is permitted).
- Intraocular surgery on the eligible eye(s) within 6 months prior to Screening 1, and any ophthalmic condition that may require surgery on the study eye during the Treatment Period. An exception to the preceding statement is allowed if, in the opinion of the Investigator, the ocular surgery is deemed the cause of the NK.
- Corneal transplantation (i.e., keratoplasty) of the study eye within the past 2 years or a history of multiple keratoplasty operations to the study eye regardless of timing. This includes full- or partial-thickness, or endothelial keratoplasty.
- Subject who is pregnant or nursing.
- Subject who is unwilling to comply with contraception requirements per-protocol (for subjects of childbearing potential).
- Subject who is known to be noncompliant or is unlikely to comply with the requirements of the study protocol, in the opinion of the Investigator.
Trial locations and contacts
9 sites in 1 country. Contact the study team or a site near you to ask about taking part.
9 sites in 1 country
United States9 sites, 9 recruiting
- Recruiting
Vance Thompson Vision
Alexandria, Minnesota, 56308
Miranda Danielson, 320-762-2166, miranda.danielson@vancethompsonvsion.com
Bailee Larson, 320-762-2166, bailee.larson@vancethompsonvision.com
- Recruiting
Midwest Cornea Associates
Carmel, Indiana, 46290
Chris Bartizal, BS, 317-805-4527, MCAresearch@midwesteye.com
- Not yet recruiting
UC Irvine Alpha Clinic
Irvine, California, 92617
UC Irvine Alpha Clinic, 949-824-3990, alphaclinic@hs.uci.edu
- Recruiting
Minnesota Eye Consultants
Minnetonka, Minnesota, 55305
Allison Dreyer, 952-567-6111, aadreyer@mneye.com
- Recruiting
Metropolitan Eye Research and Surgery Institute
Palisades Park, New Jersey, 07650
Sachi Desai, 201-461-3970, sachi@mersieye.com
- Recruiting
Azul Vision - California Eye Specialists Medical Group Inc.
Pasadena, California, 91107
Kaci Taylor, 626-792-1074, ktaylor@azulvision.com
- Not yet recruiting
UPMC Vision Institute
Pittsburgh, Pennsylvania, 15219
UPMC Vision Institute Clinical Trials Team, 412-642-7888, Clinicaltrialsoph@upmc.edu
- Recruiting
St. Louis Eye Institute
Town and Country, Missouri, 63017
Abigail Carpenter, 314-254-3818, acarpenter@stlouis-eye.com
Main Office, 314-326-4800 ext. 5
- Recruiting
Vance Thompson Vision
West Fargo, North Dakota, 58078
Hannah Christensen, 701-369-9022, Hannah.Christensen@vancethompsonvision.com
McKenzie Schueller, 701-205-0935, Mckenzie.Schueller@vancethompsonvision.com
About this study
Official title: A Phase 1/2, Multicenter, Double-Masked, Placebo-Controlled Study of KB801 in Subjects With Stage 2 or 3 Neurotrophic Keratitis
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.
Read the detailed description
Subjects will will be randomized 1:1 to receive KB801 or placebo (vehicle) topically to the study eye daily for 8 weeks. Subjects will return for a follow-up visit 2- weeks after finishing treatment to monitor for safety and durability of corneal healing. Safety follow-up visits will then occur every 3 months through approximately 1 year on study.
- Conditions
- Neurotrophic Keratitis
- Being tested
- KB801, Placebo
- Keywords
- Neurotrophic Keratitis, Persistent Corneal Epithelial Defect, Corneal Epithelial Defect
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
KB801Biological
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)
PlaceboDrug
Vehicle
| Study group | Role | What they receive |
|---|---|---|
| KB801 | Experimental | Not described Receives: Biological: KB801 |
| Placebo | Placebo comparator | Not described Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
To evaluate safety and tolerability of KB801 based upon assessment of adverse events (frequency, severity, relatedness).
Number of subjects with treatment related adverse events as assessed by CTCAE v5.
Measured: 8 weeks
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
Proportion of subjects receiving KB801 exhibiting complete PCED closure at Week 8 compared to those receiving placebo.
Measured: 8 weeks
Secondary outcomes (2)
To evaluate the effect of KB801 on complete healing of the PCED in subjects with Stage 2 or 3 NK
Proportion of subjects receiving KB801 with complete PCED closure at Weeks 4, 6 and 10 compared to those receiving placebo.
Measured: 10 weeks
To evaluate the effect of KB801 on conventional healing of the PCED in subjects with Stage 2 or 3 NK
Proportion of subjects receiving KB801 achieving <0.5-mm lesion size at Weeks 4, 6, 8, and 10 compared to those receiving placebo.
Measured: 10 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 May 2025
- Study start7 Jul 2025
- Primary completionDec 2026 (estimated)
- Study completionDec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Neurotrophic KeratitisStudies of the same condition, open and under way.
- More trials run by Krystal Biotech, Inc.The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1/2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Krystal Biotech, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06999733
- Sponsor's protocol ID
- KB801-01
- Acronym
- EMERALD-1
- Status last verified
- Feb 2026
- First submitted
- 14 May 2025
- Last updated
- 27 Feb 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 27 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1/2, Multicenter, Double-Masked, Placebo-Controlled Study of KB801 in Subjects With Stage 2 or 3 Neurotrophic Keratitis
- ClinicalTrials.gov ID
- NCT06999733
- Acronym / sponsor ID
- EMERALD-1 / KB801-01
- Conditions
- Neurotrophic Keratitis
- Keywords
- Neurotrophic Keratitis, Persistent Corneal Epithelial Defect, Corneal Epithelial Defect
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Krystal Biotech, Inc.Industry (pharma, biotech, devices)
- Study start
- 7 Jul 2025 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Dec 2027 (estimated)
- First posted
- 31 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
Subjects will will be randomized 1:1 to receive KB801 or placebo (vehicle) topically to the study eye daily for 8 weeks. Subjects will return for a follow-up visit 2- weeks after finishing treatment to monitor for safety and durability of corneal healing. Safety follow-up visits will then occur every 3 months through approximately 1 year on study.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| KB801 | Experimental | Biological: KB801 |
| Placebo | Placebo comparator | Drug: Placebo |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- 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.
- Aged ≥ 18 years at the time of informed consent.
- Diagnosis of Stage 2 or Stage 3 NK, as defined by the Mackie criteria.
- Persistent corneal epithelial defect (PCED) between Screening 1 and Screening 2 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).
- PCED at Screening 1 must have a minimum of 1 mm of any linear measurement of defect.
Key exclusion criteria (15 listed)
- An active ocular infection (bacterial, viral, fungal or protozoal) or active ocular inflammation not related to NK in the study eye as assessed by Investigator at Screening 1 or 2.
- Use of any prohibited therapies at Screening or anticipated need for topical treatments other than the investigational product or products allowed per protocol in the study eye from Screening through the study Treatment Period
- Anticipated use of therapeutic contact lenses or contact lens wear for refractive correction during the study Treatment Period in the study eye.
- Evidence of corneal ulceration involving the posterior third of the corneal stroma, corneal melting, descemetocele, impending or perforation in the study eye at the time of Screening 1 or 2.
- PCED at Screening 1 or 2 of > 8 mm maximum linear measurement in any eye.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| KB801Ophthalmic suspension of replication-defective, non-integrating herpes simplex virus type 1 (HSV-1)-based vector delivering functional, full-length human nerve growth factor (NGF) | Biological | KB801 |
| PlaceboVehicle | Drug | Placebo |
Primary outcome
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.
2 secondary outcomes
To evaluate the effect of KB801 on complete healing of the PCED in subjects with Stage 2 or 3 NK
Time frame: 10 weeks
To evaluate the effect of KB801 on conventional healing of the PCED in subjects with Stage 2 or 3 NK
Time frame: 10 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Feb 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
9 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing KB801 in people with Neurotrophic Keratitis, run by Krystal Biotech, Inc. at 9 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 27 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 9 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact David Sweet, MD, PhD (412-586-5830, dsweet@krystalbio.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
To evaluate safety and tolerability of KB801 based upon assessment of adverse events (frequency, severity, relatedness). (time frame: 8 weeks). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Feb 2026.