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editas MEDICINE Exhibit 99.1 Editas Medicine Announces Second Quarter 2021 Results and Business Updates Enrolling first pediatric and adult high dose cohorts of EDIT - 101 BRILLIANCE trial for LCA10 EDIT - 101 initial clinical data planned for September 2021 EDIT - 301 RUBY trial for sickle cell disease screening patients ; first patient on track to be dosed by year - end Strengthened leadership with appointment of Chi Li as Chief Regulatory Officer and Bruce Eaton as Chief Business Officer CAMBRIDGE , Mass . , Aug. 4 , 2021 - Editas Medicine , Inc. ( Nasdaq : EDIT ) , a leading genome editing company , today reported business highlights and financial results for the second quarter of 2021 . " We continue to make exciting progress on our clinical and preclinical programs , as well as significant advancements in our underlying gene editing platform , ” said James C. Mullen , Chairman , President , and Chief Executive Officer , Editas Medicine . “ The BRILLIANCE trial for EDIT - 101 is now enrolling the first pediatric and adult high - dose cohorts , and we look forward to presenting our Company's first clinical data next month . Patient screening is underway for our RUBY trial of EDIT - 301 for sickle cell disease , and we expect to dose our first patient by year end . In addition , we enhanced the technological capabilities of our novel engineered nucleases , and further advanced our earlier stage pipeline , including the iPSC - derived NK platform . " Recent Achievements and Outlook In Vivo Gene Edited Medicines EDIT - 101 for Leber Congenital Amaurosis 10 ( LCA10 ) IDMC endorsed proceeding with first pediatric cohort based on a review of clinical safety data ; concurrently enrolling patients in adult high - dose cohort Editas Medicine has completed dosing of the adult mid - dose cohort and , following the endorsement by the Independent Data Monitoring Committee ( IDMC ) , has opened enrollment for the first pediatric cohort . The Company is also enrolling patients in the adult high - dose cohort . Completion of dosing for both cohorts is expected in the first half of 2022 . Initial clinical data planned for the International Symposium on Retinal Degeneration ( RD2021 ) in September 2021 Initial EDIT - 101 clinical data is planned for presentation at the International Symposium on Retinal Degeneration ( RD2021 ) in September 2021 by one of the study's Principal Investigators . Data will include patient safety assessments and a preliminary analysis of secondary endpoints relating to signals of gene editing and clinical benefit . The presentation will cover cumulative data from patients in the adult low - dose and mid - dose cohorts . As