Powering a New Era of Gene Therapy

We are developing Anellovectors, the first potentially redosable and targetable gene therapy platform, by harnessing the human commensal virome.

How It Works

Flagship Pioneering Asked:
What if there is a human commensal virome? Could it be harnessed to create therapeutics?

The Commensal Virome

With recent advances in sequencing technologies and bioinformatic capabilities, we have uncovered a large family of viruses that constitute the majority of the human commensal virome. These encapsidated viruses remain as episomal DNA elements once inside the cell and have coevolved with us over millennia, joining us in an intimate symbiotic relationship. The virome, an intrinsic element of biology—present in virtually every person and a diverse array of tissues—represents an opportunity to create a gene therapy platform applicable to many diseases.


Ring has harnessed the commensal virome with the creation of Anellovectors—engineered vectors consisting of single-stranded DNA rings that, once administered, will remain as episomes in the nucleus. They have the rare potential to be harmless, transferring DNA to new cells without damaging tissues or activating the immune system.

Revolutionizing Gene Therapy

Using our proprietary Anelloscope platform, Ring Therapeutics has uncovered and characterized the world’s largest collection of commensal viruses and is harnessing those best suited for each of many diseases.

Key Features of Anellovectors

Tropism with Cellular and Tissue Specificity

Ring’s Anellovector platform promises to achieve a broad array of tissue specificities benefitting from the inherent diversity of tropism afforded by the commensal virome.

Lack of Insertional Mutagenesis

Current virus based gene therapy platforms can randomly integrate within the human genome disrupting the function of important genes. Anellovectors remain as episomes in the nucleus and do not affect the genome. This eliminates the potential risk of insertional mutagenesis, making for a safer form of gene therapy.


Existing gene therapy modalities such as adeno-associated virus (AAV)–based vectors can be administered only once in a patient’s life, because they activate the immune system. The commensal virome is ubiquitous within the human body and does not trigger any significant immune reactions. Therefore, Ring’s Anellovectors have the potential to treat patients with pre-existing immunologic barriers and/or requiring redosing.


Ring’s Anellovectors can be engineered to accommodate a wide variety of therapeutic modalities, and can be delivered via multiple routes of administration.


Ring is developing an in-house proprietary capability to rapidly scale manufacturing and explore the broad therapeutic potential of various Anellovectors. By implementing state-of-the-art manufacturing, Ring is planning to scale production to commercial levels and take the Anellovector platform from bench to bedside.

Building the Future

For many years, the promise of gene therapy to provide solutions for patients has been stymied by limited breadth, an inability to redose, and poor tolerability. Ring’s novel approach has the potential to revolutionize the field—making these challenges a thing of the past and unlocking the full potential of gene therapy and more broadly DNA medicines. We aim to expand the applications of DNA based treatments beyond gene replacement, enabling a much wider array of modalities and mechanisms, and providing access to previously unreachable tissues and organs.


Ring began as an exploration into the human commensal virome at Flagship Labs, Flagship Pioneering’s innovation foundry. Through the exploration, the founding Flagship team, composed of Avak Kahvejian, PhD; Erica Weinstein, PhD; and Noubar Afeyan, PhD, uncovered a family of viruses that were identified in transfusion samples around the turn of the century but had been largely dismissed after they were deemed non-pathogenic. The team surmised that the natural history of the virus in transfusion medicine could serve as tantalizing evidence of its safety, ubiquity, and transmissibility. The team founded a ProtoCo (prototype company), FL46, Inc., and embarked on the exciting project of mining genomic data for deeper viral discovery and “vectorizing” these viruses through synthesis and engineering. Once experimental demonstrations were successfully completed and they substantiated the potential for a broad new gene therapy platform, Flagship Pioneering launched Ring Therapeutics, Inc. as a NewCo in 2017. Learn More

About Flagship Pioneering

Flagship Pioneering conceives, creates, resources, and develops first-in-category life sciences companies to transform human health and sustainability. Since its launch in 2000, the firm has applied a unique hypothesis-driven innovation process to originate and foster more than 100 scientific ventures, resulting in over $30 billion in aggregate value. To date, Flagship is backed by more than $3.3 billion of aggregate capital commitments, of which over $1.9 billion has been deployed toward the founding and growth of its pioneering companies alongside more than $10 billion of follow-on investments from other institutions. The current Flagship ecosystem comprises 39 transformative companies, including Axcella Health, (NASDAQ: AXLA), (NASDAQ: DNLI), Evelo Biosciences (NASDAQ: EVLO), Foghorn Therapeutics, Indigo Agriculture, Kaleido Biosciences (NASDAQ: KLDO), Moderna Therapeutics (NASDAQ: MRNA), Rubius Therapeutics (NASDAQ: RUBY), Seres Therapeutics (NASDAQ: MCRB), and Syros Pharmaceuticals (NASDAQ: SYRS). To learn more about Flagship Pioneering, please visit: www.FlagshipPioneering.com.



Avak Kahvejian, PhD

Founding CEO, Partner, Flagship Pioneering

Avak is a life-sciences inventor, entrepreneur, and Ring's CEO. Since 2011, he has been a partner at Flagship Pioneering, where he leads a team that invents and launches new therapeutic platforms. His work has led to the creation of multiple high-value public and private companies, including Cellarity, a new approach to discovering drugs using single cell transcriptomics, machine learning and network biology; Cygnal Therapeutics, pioneering new drugs that target neuronal pathways for the treatment of cancer and autoimmune/inflammation disorders; Codiak BioSciences, developing engineered exosome therapeutics as cancer treatments; Rubius Therapeutics (NASDAQ: RUBY), developing Red Cell Therapeutics, engineered red blood cells capable of providing potent and prolonged therapy for rare diseases, cancer, and autoimmunity; and Seres Therapeutics (NASDAQ: MCRB), the first microbiome therapy platform.



Rahul Singhvi, ScD, MBA

President, Operating Partner, Flagship Pioneering

Rahul Singhvi, Sc.D., Operating Partner at Flagship Pioneering, serves as President of Ring Therapeutics. Until recently, Rahulwas the Chief Operating Officer of Takeda’s Global Vaccine Business Unit where he led a 300 person organization. Prior to Takeda, Rahul was President and CEO of Novavax, Inc.(NVAX), a Nasdaq listed clinical stage vaccine company. Rahul began his professional career at Merck & Co., where he held several positions in R&D and manufacturing.

Rahul is a member of the executive advisory board of the Leonard Davis Institute of Health Economics at the University of Pennsylvania. He also serves as an advisor to the Office of Technology Transfer at the University of Maryland, Baltimore and as a mentor instructor in the Undergraduate ProjectsOpportunities Program at MIT.

Rahul received his masters and doctorate degrees in chemical engineering from MIT and an MBA from the Wharton School of the University of Pennsylvania.



Simon Delagrave, PhD

Vice President, Platform and Biology

Simon is former head of virology research and interim head of research with Sanofi Pasteur North America, where he worked for 13 years. He led the development of ACAM529, a candidate vaccine against genital herpes that completed phase 1 clinical testing. Simon participated in the development of the licensed vaccine Imojev against Japanese encephalitis, and recombinant antibodies against influenza and respiratory syncytial virus. In earlier work, he applied directed evolution to discover improved enzymes and the first useful variant of the green fluorescent protein. Simon obtained a BSc in biochemistry from McGill University and a PhD from MIT in biological chemistry.



Roger J. Hajjar, MD

Head of Research and Development

Roger is an internationally renowned scientific leader in the field of cardiac gene therapy having led First-in-Human gene therapy trials in patients with heart failure. Roger was until earlier this year the Director of the Cardiovascular Research Center, and the Arthur & Janet C. Ross Professor of Medicine at Mount Sinai School of Medicine in New York. He received his MD from Harvard Medical School and the Harvard-MIT Division of Health Sciences & Technology. He completed his training in cardiology, heart failure/cardiac transplantation and research fellowships at Massachusetts General Hospital. He has authored over 500 peer-reviewed publications and has received numerous awards for his achievements in the field cardiovascular medicine.



Canwen Jiang, MD, PhD

Senior Vice President, Translational Medicine and Clinical Development

Before joining Ring, Canwen was co-founder and CEO of Sinovant Sciences. Prior to that, he served as vice president and therapeutic area head for ophthalmology and ENT at Novartis; head of clinical, medical, and regulatory affairs Asia & Russia and head of global clinical development at Alcon; and vice president of R&D and head of R&D Asia at Sanofi Genzyme. Over 25 years, he has led R&D teams to advance more than a dozen programs in several therapeutic areas to regulatory approval and commercialization. Canwen obtained medical degrees and clinical training at Hunan College of Chinese Medicine and Hunan College of Medicine and completed a cardiology fellowship at the Royal Brompton Hospital. He has a PhD in cardiology from Imperial College London and performed research at the University of California, Berkeley. He has published more than 50 scientific articles and has been granted multiple patents.



Erica Weinstein, PhD

Head of Technology and Corporate Strategy, Senior Associate, Flagship Pioneering

As a senior associate at Flagship Pioneering , Erica has played a vital role in developing multiple projects within Flagship Labs, including Cygnal Therapeutics and Inzen Therapeutics. At Flagship, Erica works as part of a team of entrepreneurial scientists exploring innovative ideas and developing the science, intellectual property, and business strategy that underlie breakthrough startups. Before joining Flagship, Erica earned her doctorate in biomedical sciences at the Icahn School of Medicine at Mount Sinai, studying the emerging role of the microbiome in autoimmune disease development. During her studies, Erica received Helmsley Charitable Trust Fellowship and Levine Foundation Fellowship awards. She is an author on numerous academic publications. Business Insider recently named Erica to its list of 30 biotech leaders under 40.



Nathan Yozwiak, PhD

Director of Viral Genomics

Nathan Yozwiak joined Ring Therapeutics in 2018 as Director of Viral Genomics.

Before joining Ring, Nathan was Associate Director of Viral Genomics at the Broad Institute of MIT and Harvard, where he studied virus evolution, genomic diagnostics, and outbreak surveillance. He helped establish the World Bank-funded African Center of Excellence for Genomics of Infectious Disease (ACEGID) at Redeemer's University, Nigeria, which provided critical insights into the detection and spread of pathogens, including the first extensive genomic characterization of the 2014-16 West Africa Ebola outbreak. Nathan has provided consultations to the World Health Organization on public health emergencies. Nathan received his PhD in Infectious Diseases from U.C. Berkeley and his BS in Molecular and Cellular Biology from Johns Hopkins. He completed his doctoral studies in Joe DeRisi’s lab at UCSF, where he studied detection and discovery of known and novel viruses in pediatric illnesses using viral microarrays and deep sequencing technology, including one of the first clinical metagenomic studies.



Sadettin Ozturk, PhD


Sadettin has 30 years of experience in biopharmaceutical process development, technology transfer, product licensing, and commercial manufacturing. He led process and technology development and manufacturing activities at Verax, Bayer, GlaxoSmithKline, Johnson & Johnson, and MassBiologics, played a vital role in the licensing and commercialization of Stelera®, Simponi®, and Sylant® and he transferred and supported the commercial manufacturing of Kogenate®, BeneFix®, and Remicade®. His activities later expanded to the vaccine production and Cell and Gene Therapy applications for AAV and Lentivirus based vector manufacturing.

Sadettin is a member of several societies and currently serving ACS as a long-term Councilor. He has also published books, more than 50 scientific articles, delivered many keynote speeches, and co-authored several patents. Sadettin has a MS in Chemical Engineering from the University of Ankara, Turkey, a PhD from the University of Michigan, Ann Arbor., and an MBA certificate from UC Berkeley, Haas School of Business.

Board of Directors


Founder & CEO, Flagship Pioneering


Senior Partner, Flagship Pioneering


Senior Vice President Manufacturing, Rubius Therapeutics


Founding CEO, Ring Therapeutics; Partner, Flagship Pioneering

Advisory Team


Adjunct Professor & Gene Therapy Innovator, UMass Medical School


Professor, Stanford University


Professor, University of California, San Francisco


Independent Consultant; Founder and President, Q-One Biotech


Associate Professor, Scripps Research


Chief Technical Operations and Quality Officer, Moderna Therapeutics


Ring Therapeutics co-founder and Senior Associate, Flagship Pioneering


Operating Partner, Flagship Pioneering