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editas MEDICINE Editas Medicine Announces Positive Initial Clinical Data from Ongoing Phase 1/2 BRILLIANCE Clinical Trial of EDIT - 101 for LCA10 September 29 , 2021 No serious adverse events or dose - limiting toxicities observed to date Efficacy signals in the mid - dose cohort provide initial support for clinical benefits Treatment in the adult high - dose cohort continues and pediatric mid - dose cohort commencing Data presented in an oral presentation at the International Symposium on Retinal Degeneration Company to host a webcast today at 11:00 a.m. ET CAMBRIDGE , Mass . , Sept. 29 , 2021 ( GLOBE NEWSWIRE ) -- Editas Medicine , Inc. ( Nasdaq : EDIT ) , a leading genome editing company , today announced positive initial clinical data from the ongoing , open label Phase 1/2 BRILLIANCE clinical trial of EDIT - 101 . EDIT - 101 is under development for the treatment of blindness due to Leber congenital amaurosis 10 ( LCA10 ) , a CEP290 - related retinal degenerative disorder . The data , including preliminary patient safety and efficacy assessments relating to potential clinical benefits , are being presented today in an oral presentation at the XIXth International Symposium on Retinal Degeneration ( RD2021 ) by Dr. Mark Pennesi , M.D. , Ph.D. " The preliminary results shared today support our belief that EDIT - 101 has the potential to provide meaningful benefits to people living with CEP290 related retinal degeneration or LCA10 . A positive safety profile has been observed through up to 15 months , with mostly mild adverse events primarily related to the procedure of retinal injection . The safety profile has allowed us to start enrolling and treating subjects in both the high - dose adult cohort and the mid - dose pediatric cohort . Early observations from individuals who were treated in the mid - dose cohort show clinical evidence that gene editing has occurred , demonstrated by visual improvements , as measured by full - field light sensitivity threshold ( FST ) testing , best corrected visual acuity ( BCVA ) , or improvement in their ability to navigate standardized navigation courses with varying levels of difficulty . We will continue to follow the trial participants prospectively and collect clinical measures to allow us to determine the extent of both continued and durable improvements , " said Lisa Michaels , M.D. , Executive Vice President and Chief Medical Officer , Editas Medicine . " I would like to thank the participants , clinicians , and collaborating institutions that continue to contribute to this landmark gene editing medicine clinical trial . " " I am encouraged by these initial results , which indicate this investigational gene editing treatment has been well - tolerated in this trial's participants thus far and may also help improve sight for people with mutations in the CEP290 gene . Being able to edit genes inside the human body is incredibly profound , and I hope to be able to offer my LCA patients new treatment options involving gene editing in the future , " said Mark Pennesi , M.D. , Ph.D. , Professor of Molecular and Medical Genetics , Kenneth C. Swan Endowed Professor of Ophthalmology , Paul H. Casey Ophthalmic Genetics Division Chief , Casey Eye Institute , Oregon Health & Science University , and a BRILLIANCE principal investigator . Dr. Michaels added , " These encouraging results provide a proof of concept on our in vivo gene editing platform and increase Editas ' confidence in the broad potential of our gene editing technology to address additional serious diseases . " Preliminary Results Preliminary results include safety and efficacy data from the first two cohorts , the adult low - dose cohort ( 6x1011 vg / ml ) and the adult mid - dose cohort ( 1.1x1012 vg / ml ) . The BCVA eligibility criteria for the adult low - dose cohort ( n = 2 ) are light perception ( LP ) , black - white discrimination , and white field projection . For the adult mid - dose and all other cohorts , the first subject is required to have light perception to BCVA of 1.6 logMAR ( 20/800 Snellen ) . BCVA criteria for all subsequent subjects is LP to 0.4 logMAR ( 20/50 Snellen ) . Safety Safety data was reported with respect to all six subjects treated in the low dose ( n = 2 ) and mid - dose ( n = 4 ) cohorts . Most adverse events ( AES ) were mild and primarily resulting from the surgical procedure and subretinal injection . There were no dose limiting toxicities ( DLTS ) defined as a vision - threatening toxicity or severe non - ocular AE that occurs before or at the Week 4 visit and is assessed by the investigator as being related to EDIT - 101 and not the administration procedure . Mild anterior chamber inflammation was observed , and adequately controlled with oral steroids . No Cas9 - specific antibody or T - cell response was detected . To date , no treatment - related cataracts , edema , or retinal thinning have been observed . Efficacy Efficacy was assessed based on available data from five subjects treated in the adult low - dose cohort ( n = 2 ) and the adult mid - dose cohort ( n = 3 ) , who had at least three months of post treatment follow - up , focusing on those measures demonstrated to be consistent and reproducible in subjects with CEP290 retinal degeneration , including : BCVA , FST , and Visual Function Navigation ( VNCTM , developed byOra . Inc. ) . Two of three subjects in the mid - dose cohort followed for up to six months showed efficacy signals suggesting productive editing and providing initial support for clinical benefits , including improvements in BCVA , FST , and / or mobility navigation . BCVA is assessed by using the Early Treatment of Diabetic Retinopathy Study ( ETDRS ) eye chart , or the Berkeley Rudimentary Vision Test ( BRVT ) , or the Lea Symbols 15 - line pediatric eye chart . FST measures the sensitivity of the entire visual field by testing for the lowest luminance flash which provokes a visual sensation . Patients are presented with blue , red , and white stimuli , and based on the blue - red difference , the experimenter can determine the sensitivity of rod - mediated and cone - mediated perceptions . Navigational capabilities were assessed using standardized mobility testing with four different navigation courses , designed with varying levels of difficulty . Mid - dose cohort Subject 1 showed improvement in BCVA of approximately 0.7 logMAR at Month 1.5 which was sustained at Month 6 follow - up .