Rubius Therapeutics, a biotechnology company pioneering the development of a new class of extraordinarily active and differentiated cell therapies, announced today that it has raised $120 million in a highly oversubscribed private financing. Rubius has developed the technology to grow, genetically engineer and mature long-circulating red cell therapeutics which will provide transformational clinical benefits to a wide range of patients across multiple therapeutic areas. These allogeneic, off-the-shelf products offer the additional advantage of extended stability and storage to allow for rapid, universal access by the medical community. Proceeds will be used to accelerate the advancement of Rubius' breakthrough Red-Cell Therapeutics (RCT) product portfolio, to further build out the team and to prepare to enter human clinical trials in 2018. This financing follows the successful achievement of several key milestones, including the clinical scale production of cultured red cells in bioreactors and the generation of preclinical proof-of-concept data for several lead programs.

"With this financing, Rubius is well positioned to focus on the continued development of our platform to advance a broad range of therapeutic candidates that have the potential to make a significant difference in the lives of patients," said Torben Straight Nissen, Ph.D., President of Rubius Therapeutics.

"Rubius has achieved multiple scientific and manufacturing milestones in the first six months of this year. Those achievements plus the trust that Flagship and our new investors have put in Rubius with this financing sets us up to turn our RCTs into important new treatment options," said David Epstein, Chairman of Rubius Therapeutics and Executive Partner of Flagship Pioneering.

The RCT platform allows Rubius to express enzymes, agonists, antagonists, binders and combinations in their natural conformation on or inside of red cells. Lead RCT programs include enzyme replacement therapies as well as therapies targeting solid tumors and hematological cancers. Further, Rubius has demonstrated that RCTs provide potential applications across additional therapeutic areas, such as autoimmune disease, infectious disease, metabolic disease and rare diseases, including hemophilia.

"We are excited to expand our support of Rubius in this next round of funding as the company continues to advance its technology and programs -- following in the footsteps of Flagship's family of successful multiproduct platform companies," said Noubar Afeyan, CEO of Flagship Pioneering and Co-Founder of Rubius. "The team at Rubius has made great strides over the past three years and we are pleased to support the company's continued growth. This new financing, together with a leadership team with unparalleled expertise, positions Rubius to deliver on the promise of the RCT platform and bring transformative therapies to patients."

Rubius was conceived, launched and funded by Flagship VentureLabs, the innovation foundry of Flagship Pioneering. Joined by undisclosed large institutional investors, Flagship Pioneering significantly increased its investment in this financing.

About Red-Cell Therapeutics

Red-Cell Therapeutics are genetically engineered, enucleated red cells that provide allogeneic, off-the-shelf therapies to patients across multiple therapeutic areas. RCT advantages over other therapies include immuno-privileged presentation of proteins within or on the red cell, high target avidity and affinity resulting in highly potent and selective therapies, and long circulation half-life. Rubius RCTs exhibit fundamentally unique biology and have been engineered to replace missing enzymes for patients living with a variety of rare diseases, to kill tumors, and upregulate or downregulate the immune system to treat both cancer and autoimmune disorders.

About Rubius Therapeutics

Rubius Therapeutics is developing Red-Cell Therapeutics (RCTs) as a new class of medicines to address a wide array of indications, with leading applications in cancer, rare and autoimmune disease, as well as additional potential in hemophilia, infectious and metabolic diseases. The company was founded and launched in 2014 by Flagship VentureLabs, the innovation foundry of Flagship Pioneering. Rubius has successfully engineered and manufactured red cells that express therapeutic proteins for use in the treatment of serious diseases. The company is now demonstrating that these newly equipped high performing, off-the-shelf Red-Cell Therapeutics have pre-clinical activity across a spectrum of medical applications. Rubius has generated more than 200 prototypes to date. For more information, please visit www.rubiustx.com.

About Flagship Pioneering

Flagship Pioneering conceives, creates, resources and develops first-in-category life sciences companies. Its institutional innovation foundry, Flagship VentureLabs, is where Flagship's team of scientific entrepreneurs systematically evolves enterprising ideas into new fields, or previously undiscovered areas of science into real-world inventions and ventures. Since its launch in 2000, the firm has applied its hypothesis-driven innovation process to originate and foster nearly 100 scientific ventures, resulting in over $20 billion in aggregate value, 500+ issued patents and more than 45 clinical trials for novel therapeutic agents.

Since inception, Flagship has capitalized its growing portfolio with over $1 billion coming from $1.75 billion of aggregate investor capital committed across five funds. The firm's current portfolio includes pioneering ventures that are transforming human health and sustainability, including: Agios Pharmaceuticals (NASDAQ: AGIO), Editas Medicine (NASDAQ: EDIT), Seres Therapeutics (NASDAQ: MCRB) and Syros Pharmaceuticals (NASDAQ: SYRS), as well as private companies, including Axcella Health, Indigo Agriculture, Moderna Therapeutics and Rubius Therapeutics. Flagship has ongoing corporate innovation alliances with several market leaders, including: AstraZeneca, the Crop Science Division of Bayer and Nestlé Health Science. To learn more about Flagship Pioneering, please visit our website: www.FlagshipPioneering.com.