8-K: Krystal Biotech Initiates Phase 1/2 Clinical Trial for KB801 in Neurotrophic Keratitis

Krystal Biotech announced the dosing of the first patient in its Phase 1/2 EMERALD-1 clinical trial for KB801, an investigational eye drop gene therapy for neurotrophic keratitis.

Summary

• The first patient has been dosed in the Phase 1/2 EMERALD-1 clinical trial evaluating KB801 for the treatment of neurotrophic keratitis (NK).
• KB801 is a redosable eye drop gene therapy designed to enable sustained, localized expression of nerve growth factor (NGF) in the front of the eye.
• Neurotrophic keratitis is a rare, degenerative corneal disease with an estimated prevalence of 10 to 50 cases per 100,000.
• Claims data analyses suggest awareness and diagnosis rates for NK are rising in the United States, with an estimated 68,000 patients having an NK claim in 2024, an increase of over 115% from 31,000 patients in 2020.
• The EMERALD-1 study is a 2:1 randomized, double-masked, multicenter, placebo-controlled trial enrolling up to 27 adults with Stage 2 or Stage 3 NK.
• Patients will receive KB801 at a concentration of 10^10 PFU/mL or placebo topically to the study eye twice weekly for 8 weeks.
• The primary objective of EMERALD-1 is to evaluate the safety and tolerability of topical ocular administration of KB801.
• The secondary objective is to evaluate efficacy based on the proportion of patients with complete durable healing of corneal epithelium at 8 weeks, defined as 0 mm corneal fluorescein staining at both week 8 and week 10.
• Krystal Biotech also initiated its Phase 3 IOLITE study for KB803 in ocular complications of dystrophic epidermolysis bullosa (DEB) in Q2 2025.
• An investor conference call and webcast were held on July 9, 2025, to discuss the KB801 program and clinical study design.

Sentiment

Score: 8

Explanation: The announcement marks a significant advancement in Krystal Biotech's ophthalmology pipeline with the initiation of a Phase 1/2 trial for a promising gene therapy targeting a high unmet medical need. Preclinical data supports the therapy's potential for superior efficacy and reduced treatment burden compared to existing options, indicating strong positive momentum for the company's pipeline.

Positives

• The dosing of the first patient in the EMERALD-1 trial marks a significant advancement in the ophthalmology pipeline.
• KB801 is designed as a redosable eye drop gene therapy, offering the potential to significantly reduce the treatment burden for neurotrophic keratitis patients compared to current therapies.
• Preclinical data for KB801 demonstrated sustained NGF expression, achieving higher peak levels and remaining elevated days after administration compared to recombinant protein comparators.
• The company's HSV-1 based platform has shown safety and efficacy of repeat dosing with B-VEC eye drops in compassionate use cases for DEB patients, supporting its suitability for front-of-the-eye applications.
• Krystal Biotech is pursuing Platform Technology Designation with the FDA, which could lead to expedited development and streamlined regulatory interactions for its HSV-1 platform.
• The clinical development path for KB801 is expected to be relatively short and cost-effective, with safety, efficacy, and CMC significantly derisked by prior experience with Oxervate and the HSV-1 platform.
• The VYJUVEK franchise is poised for multiple years of steady growth in the U.S. and through global expansion.
• The potential launch of KB803, if approved, is highly synergistic with VYJUVEK, driving further top-line and bottom-line growth.
• Pipeline efforts in lung and eye indications are viewed as springboards for multi-product opportunities in large markets.

Negatives

• The only specific FDA-approved therapy for neurotrophic keratitis, Oxervate, requires highly burdensome administration six times daily for 8 weeks, limiting its therapeutic utility and leading to suboptimal outcomes.
• Eye pain is the most common adverse event associated with Oxervate, compounding the burden of frequent dosing.

Risks

• Uncertainties are inherent in the initiation and conduct of clinical trials.
• Regulatory review of clinical trials and applications for marketing approvals involves uncertainties.
• There are uncertainties regarding the availability or commercial potential of product candidates.
• Forward-looking statements are subject to various important factors, including those set forth under the caption 'Risk Factors' in the company's annual and quarterly reports on file with the U.S. Securities and Exchange Commission.

Future Outlook

KB801 has the potential to significantly reduce the treatment burden for neurotrophic keratitis patients while maintaining more consistent NGF levels. Awareness and diagnosis rates for NK are expected to continue rising in the United States. The clinical development path for KB801 is anticipated to be relatively short and cost-effective. Krystal Biotech is pursuing Platform Technology Designation with the FDA, which could lead to earlier, expanded, or accelerated FDA interactions and potentially leverage prior CMC validation for streamlined development. The VYJUVEK franchise is poised for steady growth, and KB803, if approved, is expected to be highly synergistic, driving further top-line and bottom-line growth. Pipeline efforts in lung and eye indications are seen as springboards for multi-product opportunities in blockbuster markets. Data readouts from pipeline products are expected in 2025, with potential registrations for KB803 in 2026 and KB801 in 2027.

Management Comments

• "Our ophthalmology pipeline is well under way with the dosing of our first patient in EMERALD-1, along with initiation of our Phase 3 IOLITE study in DEB," said Suma Krishnan, President, Research & Development, Krystal Biotech, Inc.
• "Until now, rapid protein clearance rates and high cell turnover in the front of the eye have severely limited the therapeutic potential of biologics and gene therapies for the treatment of corneal epithelial defects and other front of the eye diseases. We now have an opportunity to drive sustained expression and repeat administration of therapeutic biologic payloads with a simple eye drop application and look forward to delivering meaningful benefit to NK patients in need," stated Suma Krishnan.

Industry Context

Neurotrophic Keratitis (NK) is a rare, degenerative corneal disease with a growing patient population in the U.S., as evidenced by a 115% increase in NK claims from 2020 to 2024. The current standard of care, Oxervate, while effective, presents significant challenges due to its intensive 6x daily dosing regimen and associated patient burden. Krystal Biotech's KB801, a redosable eye drop gene therapy, aims to address this unmet need by providing sustained NGF expression with a less frequent administration, potentially offering a superior therapeutic profile. This development aligns with the broader industry trend of advancing gene therapies for rare diseases and leveraging platform technologies for multiple indications, as demonstrated by Krystal's HSV-1 platform and its application in both NK and DEB.

Comparison to Industry Standards

• **Oxervate (cenegermin-bkbj):** The only specific FDA-approved therapy for neurotrophic keratitis, approved in 2018. It has shown 4-week healing rates in the range of 50-60% and 8-week healing rates (primary endpoint) in the range of 65-75%. However, it requires highly burdensome 6x daily dosing for 8 weeks, and eye pain is its most common adverse event. U.S. Medicaid and Medicare spend on Oxervate exceeded $540 million in 2023.
• **KB801:** Designed to overcome the limitations of Oxervate by enabling sustained, localized NGF expression with a significantly reduced dosing frequency (twice weekly in the EMERALD-1 trial). Preclinical data indicates KB801 achieves higher peak NGF levels and maintains elevation for days, suggesting a superior pharmacokinetic profile compared to recombinant protein comparators.
• **B-VEC eye drops (beremagene geperpavec):** Krystal's HSV-1 platform has demonstrated safety and efficacy of repeat dosing under compassionate use in a Dystrophic Epidermolysis Bullosa (DEB) patient with ocular complications, leading to full corneal healing and significant visual acuity improvement. This prior success with the same vector platform supports the potential for KB801 in other ocular applications.

Stakeholder Impact

• **Patients (Neurotrophic Keratitis):** Potential for a significantly improved treatment experience with a redosable eye drop gene therapy that could reduce dosing frequency from six times daily to twice weekly, potentially leading to better adherence and outcomes.
• **Shareholders:** Positive impact due to the advancement of a key pipeline asset into clinical trials, which could unlock significant long-term growth and shareholder value through new product opportunities and the expansion of the company's genetic medicines portfolio.
• **Healthcare Providers:** A potential new, more convenient, and effective therapeutic option for managing neurotrophic keratitis, addressing current treatment challenges.

Next Steps

• Continue the Phase 1/2 EMERALD-1 clinical trial for KB801 in neurotrophic keratitis patients.
• Continue the Phase 3 IOLITE study for KB803 in patients with ocular complications of DEB.
• Anticipate data readouts from pipeline products in 2025.
• Pursue expedited development and potential registrations for KB803 in 2026 and KB801 in 2027.
• Leverage the HSV-1 platform for potential multi-product opportunities in lung and eye indications.

Key Dates

Keywords

Krystal Biotech, KB801, Neurotrophic Keratitis, Gene Therapy, Clinical Trial, EMERALD-1, Ophthalmology, Rare Disease, HSV-1, Eye Drop, NGF, Biologics, VYJUVEK, KB803, Dystrophic Epidermolysis Bullosa, Biotechnology, Clinical Development, FDA, SEC Filing