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.



Tuyen Ong, MBA, MD

CEO, Ring Therapeutics;
CEO Partner, Flagship Pioneering

Dr. Ong is a Physician, Bioentrepreneur and Ring's CEO. Prior to joining Ring Therapeutics, Dr. Ong served as Senior Vice President at Biogen. Previously, Dr. Ong served as Chief Development Officer at Nightstar Therapeutics up until its acquisition by Biogen. During this time, he was involved with the company’s public listing on the NASDAQ, corporate and gene therapy strategy, investor, and M&A activities. Dr. Ong brings over 20 years of clinical and drug development experience from both large pharma and biotech, working in the fields of genetic, ophthalmology, and rare disease at PTC Therapeutics Inc., Bausch and Lomb Inc. (acquired by Valeant Pharmaceuticals International, Inc.), and Pfizer.

Dr. Ong holds an M.D. from the University College London and an M.B.A. from New York University Stern School of Business. He is a member of the Royal College of Ophthalmologists and a Churchill Fellow.



Simon Delagrave, PhD

VP of 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.



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


Founder, Ring Therapeutics; Partner, Flagship Pioneering


CEO, Ring Therapeutics; CEO Partner, Flagship Pioneering


Executive Partner, Flagship Pioneering

Advisory Team


Associate Professor, Scripps Research


EVP, Bioprocess & Manufacturing and CTO


Professor, University of California, San Francisco


Operating Partner, Flagship Pioneering


Founder, Ring Therapeutics; Partner, Flagship Pioneering


Professor, Stanford University


Adjunct Professor & Gene Therapy Innovator, UMass Medical School


Independent Consultant; Founder and President, Q-One Biotech


Operating Partner, Flagship Pioneering


Ring Therapeutics co-founder and Senior Associate, Flagship Pioneering