Studies in non-human primates demonstrated nearly 100% gene editing and knockout of endogenous RHO gene and more than 30% replacement protein levels using a dual vector AAV approach

Treated eyes showed morphological and functional photoreceptor preservation 

EDIT-103 advancing towards IND-enabling studies

CAMBRIDGE, MA, USA I October 13, 2022 I Editas Medicine, Inc. (Nasdaq: EDIT), a leading genome editing company, today announced ex vivo and in vivo preclinical data supporting its experimental medicine EDIT-103 for the treatment of rhodopsin-associated autosomal dominant retinitis pigmentosa (RHO-adRP). The Company reported these data in an oral presentation today at the European Society of Gene and Cell Therapy 29th Annual Meeting in Edinburgh, Scotland, UK.

EDIT-103 is a mutation-independent CRISPR/Cas9-based, dual AAV5 vectors “knockout and replace” (KO&R) therapy to treat RHO-adRP. This approach has the potential to treat any of over 150 dominant gain-of-function rhodopsin mutations that cause RHO-adRP with a one-time subretinal administration.

“These promising preclinical data demonstrate the potential of EDIT-103 to efficiently remove the defective RHO gene responsible for RHO-adRP while replacing it with an RHO gene capable of producing sufficient levels of RHO to preserve photoreceptor structure and functions. The program is progressing towards the clinic,” said Mark S. Shearman, Ph.D., Executive Vice President and Chief Scientific Officer, Editas Medicine. “EDIT-103 uses a dual AAV gene editing approach, and also provides initial proof of concept for the treatment of other autosomal dominant disease indications where a gain of negative function needs to be corrected.”

Key findings include:

  • In human retina explants, EDIT-103 demonstrated highly specific editing with no off-target editing observed after transduction.
  • In a mRhohRHO/+ mouse model, EDIT-103 achieved rapid gene editing, with maximal levels at six (6) weeks and sustained, stable editing until end of study (13 weeks).
  • In non-human primates (NHPs), EDIT-103 demonstrated nearly 100% knockout of endogenous RHO, and the replacement RHO gene produced over 30% of normal RHO protein levels in the treated area of subretinal injection.
  • The EDIT-103 (KO&R)-injected eyes of NHPs showed restoration of RHO expression in the outer segments and retention of normal photoreceptor structure and function compared to the KO-injected eye.
Presentation Session Information:
Presentation Title: A Mutation-Independent CRISPR/Cas9-based ‘Knockout and Replace’ Strategy to Treat Rhodopsin-Associated Autosomal Dominant Retinitis Pigmentosa
Session Title: Gene and epigenetic editing II 
Session Date and Time: October 13, 2022, from 8:30 a.m. to 10:45 a.m. BST (3:30 – 5:45 a.m. EDT)
Presenter: Mariacarmela Allocca, Director, In Vivo Pharmacology &Toxicology, In Vivo Gene Editing, Editas Medicine
Location: Edinburgh International Conference Centre, Sidlaw Auditorium
Editas scientists are also presenting EDIT-202 preclinical data in a Poster session:
Presentation Title: EDIT-202, an AsCas12a and SLEEK™ gene-edited iPSC-derived NK cell therapy maintains prolonged persistence, high cytotoxicity, and enhanced in vivo control of solid tumors​.
Session Date and Time: October 13, 2022, from 5:30 – 7:15 p.m. BST (12:30 – 2:15 p.m. EDT)
Presenter: Samia Khan, Senior Scientist II, Ex Vivo Pharmacology, Stem Cell Therapies, Editas Medicine
Location: Edinburgh International Conference Centre

Full details of the Editas Medicine presentations can be accessed in the Posters & Presentations section on the Company’s website.

About EDIT-103
EDIT-103 is a CRISPR/Cas9-based experimental medicine in preclinical development for the treatment of rhodopsin-associated autosomal dominant retinitis pigmentosa (RHO-adRP), a progressive form of retinal degeneration. EDIT-103 is administered via subretinal injection and uses two adeno-associated virus (AAV) vectors to knockout and replace mutations in the rhodopsin gene to preserve photoreceptor function. This approach can potentially address more than 150 gene mutations that cause RHO-adRP.

About Editas Medicine
As a leading genome editing company, Editas Medicine is focused on translating the power and potential of the CRISPR/Cas9 and CRISPR/Cas12a genome editing systems into a robust pipeline of treatments for people living with serious diseases around the world. Editas Medicine aims to discover, develop, manufacture, and commercialize transformative, durable, precision genomic medicines for a broad class of diseases. Editas Medicine is the exclusive licensee of Harvard and Broad Institute’s Cas9 patent estates and Broad Institute’s Cas12a patent estate for human medicines. For the latest information and scientific presentations, please visit

SOURCE: Editas Medicine