Excision BioTherapeutics Announces Oral Presentation of Preclinical HSV-1 Keratitis Data at CRISPRMED24 Conference on April 24, 2024

Treatment with EBT-104 resulted in over 90% reduction in viral shedding in HSV-1 Keratitis model

SAN FRANCISCO, April 22, 2024 (GLOBE NEWSWIRE) — Excision BioTherapeutics, Inc. (“Excision”, the “Company”), a clinical-stage biotechnology company developing CRISPR-based therapies to cure serious latent viral infectious diseases, today announced that it will deliver an oral presentation highlighting new data from its herpes simplex virus-1 keratitis (HSV-1 Keratitis) program, EBT-104, at CRISPRMED24, the CRISPR Medicine Conference, which is being held from April 23-25 in Copenhagen, Denmark.

Excision’s EBT-104 is a CRISPR-based gene therapy that is being developed as a potential cure for HSV-1 Keratitis. EBT-104 utilizes a CRISPR/Cas gene editing system to inactivate the latent HSV-1 virus.

“This research marks a significant advancement in our understanding and treatment of HSV-1 keratitis and further demonstrates the broad potential of our unique gene editing platform to treat latent viral infections,” said Daniel Dornbusch, Chief Executive Officer of Excision. “The exceptional in vivo efficacy demonstrated by our gene editing approach offers new hope for patients suffering from this debilitating condition. We look forward to sharing these new data from our EBT-104 program at the first CRISPRMED24 Conference.”

To assess the efficacy of CRISPR/Cas9-mediated gene editing on HSV-1 in vivo, a single all-in-one AAV8(Y733F) and AAV9 vectors delivery of SaCas9 and paired gRNAs were employed in a latent rabbit model of HSV-1 keratitis via corneal scarification. This approach led to a remarkable reduction of over 60% in viral shedding from the treated rabbit eyes. Building upon this success, the intravenous administration of all-in-one AAV8(Y733F) and AAV9 vectors expressing SaCas9 and paired gRNAs was explored in the same rabbit model. Impressively, 91.7% (11/12) of treated eyes exhibited no viral shedding. Even at low AAV dose (6E+12 VG/kg), we observed significant levels of AAV vector genomes in the trigeminal ganglia (TG) where the latent HSV-1 resides. Additionally, we detected reduced copies of HSV-1 viral DNA and latency-associated transcript (LAT) RNA in the trigeminal ganglia (TG) of rabbits treated with the AAV9-SaCas9 vector compared to the control group. These results demonstrate that the delivery of all-in-one AAV9-SaCas9 vectors can serve as an effective and safe one-time therapeutic strategy for treating HSV-1 keratitis.

About Herpes Simplex Keratitis

Herpes Simplex Keratitis (HSK) caused by the infection of herpes simplex virus type 1 (HSV-1) in the cornea is a major cause of blindness worldwide. Although current anti-HSV-1 therapies interfere with viral DNA replication, they do not eliminate HSV-1 reservoirs or prevent recurrence. CRISPR/Cas-mediated gene editing can potentially address the underlying causes of the disease by directly eliminating the latent HSV-1 reservoirs.

About Excision BioTherapeutics, Inc.
Excision BioTherapeutics, Inc. develops CRISPR-based medicines as potential cures for serious viral latent infectious diseases. The Company’s proprietary, multiplexed gene editing platform unites CRISPR technologies with a novel gene editing approach which demonstrated the ability to stop viral replication. Excision’s pipeline targets large, underserved markets including herpes simplex virus (HSV-1 keratitis), hepatitis B virus (HBV), and human immunodeficiency virus-1 (HIV-1). Excision’s foundational technologies were developed in the laboratories of Dr. Kamel Khalili at Temple University and Dr. Jennifer Doudna at the University of California, Berkeley. For more information, please visit www.excision.bio.

Contact:
John Fraunces
LifeSci Advisors
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jfraunces@lifesciadvisors.com