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Exhibit 99.1 • ☑Selecta . of Biosciences • • Selecta Biosciences Reports First Quarter 2021 Financial Results and Provides Business Update SEL - 399 ( empty AAV8 capsid with ImmTOR ) study on track with topline data expected in the fourth quarter of 2021 SEL - 212 enrollment on track with topline data from DISSOLVE phase 3 program expected in second half of 2022 IND filing for IgA nephropathy program expected by the end of 2021 IND filing for wholly - owned gene therapy program in MMA expected by the end of 2021 ; IND in OTC deficiency gene therapy program expected in 2022 As of March 31 , 2021 , Selecta had approximately $ 149.2 million in cash , cash equivalents , and marketable securities which is expected to provide runway into the second quarter of 2023 WATERTOWN , Mass . , May 13 , 2021 ( GLOBE NEWSWIRE ) -- Selecta Biosciences , Inc. ( NASDAQ : SELB ) , a biotechnology company leveraging its clinically validated ImmTOR ™ platform to develop tolerogenic therapies that selectively mitigate unwanted immune responses , today reported financial results for the first quarter ended March 31 , 2021 and provided a business update . " We are very pleased about the continued progress across all aspects of the company , ” said Carsten Brunn , Ph.D. , president and chief executive officer of Selecta . " We regained exclusive rights to our MMA program and now have two proprietary gene therapy programs to rapidly follow our ongoing empty capsid study . Additionally , we continue to progress our enzyme program , with an expected IND filing by the end of 2021 in IgA nephropathy , and topline data from the Phase 3 DISSOLVE program for SEL - 212 anticipated in the second half of 2022. " Recent Highlights and Anticipated Upcoming Milestones : Enzyme Therapies : • • SEL - 212 for chronic refractory gout : Enrollment for the Phase 3 DISSOLVE clinical program for SEL - 212 for the treatment of chronic refractory gout , which was licensed to Sobi , is progressing as planned with topline data expected in the second half of 2022 . Leveraging the success of SEL - 212 , Selecta expects to file an Investigational New Drug , or IND , application by the end of 2021 for a novel therapeutic approach that combines ImmTOR with an enzyme , IgA1 protease for the treatment of IgA nephropathy . Gene Therapies : • • First - in - human trial of SEL - 399 : In collaboration with AskBio , Selecta initiated the first - in - human , dose - escalation trial of SEL - 399 , an adeno - associated viral serotype 8 ( AAV8 ) empty vector capsid ( EMC - 101 ) containing no DNA combined with ImmTOR . The trial aims to determine the optimal dose of ImmTOR to mitigate the formation of antibodies to AAV8 capsids used in gene therapies . Selecta and AskBio expect to report topline data in the fourth quarter of 2021 . MMA - 101 for methylmalonic acidemia ( MMA ) : Selecta regained exclusive rights to its lead gene therapy program in MMA from AskBio and expects to file an IND in MMA - 101 , in combination with ImmTOR , by the end of 2021. The phase 1/2 MMA - 101 program , which is expected to commence in 2022 , will evaluate biomarkers of efficacy , neutralizing antibodies and safety and tolerability . SEL - 313 for ornithine transcarbamylase deficiency ( OTC deficiency ) : Selecta's proprietary gene therapy product candidate , SEL- 313 , is being developed to treat OTC deficiency , a rare genetic urea cycle disorder that causes ammonia to accumulate in the blood due to mutations in the OTC gene . SEL - 313 is currently in preclinical development and a clinical trial application , or CTA and / or IND filing are expected in 2022 . 1