[Updated 6/21/17, 4:05 pm. See below.] The main role of red blood cells is to carry life-sustaining oxygen throughout the body. Rubius Therapeutics believes these cells can carry something more: therapeutic payloads delivered directly to the organs and tissues of patients with severe diseases.
Less than two years after launch, Cambridge, MA-based Rubius has reeled in $120 million in funding from Cambridge-based venture firm Flagship Pioneering and other investors to bring therapies into clinical trials as soon as next year.
Rubius is engineering red blood cells to carry disease-fighting proteins either inside the cell or on the cell’s surface. Torben Straight Nissen, a former Pfizer (NYSE: PFE) executive who joined Rubius as its president in January, calls red blood cells a “potent and convenient” way to deliver a drug and likens them to engineered immune cells that are becoming cancer-fighting drugs in their own right. “The platform is more than a delivery vehicle,” says Straight Nissen. “It’s a cell therapy.” [Paragraph updated to clarify description of the therapy.]
These cells naturally circulate in the blood stream, with a life span of up to 120 days, he says. That means that a red blood cell therapeutic could potentially have a much longer effect compared to other mechanisms of drug delivery.
The concept has been studied for years but has yet to reach human trials. At the Joint School of Biomedical Engineering at North Carolina State University and the University of North Carolina at Chapel Hill, researchers are studying how to use red blood cells to deliver insulin faster and more precisely.
In a study published in January, researchers at the University of Pennsylvania researchers said that drugs the loading of “many drugs” has been successfully demonstrated, both inside red blood cells as well as onto the cells’ surface. These drugs include anti-inflammatory, anti-microbial, and anti-clotting medicines. But they offered some caveats: internal loading can disrupt the cell membrane, for example.
Rubius produces its red blood cells from donated human stem cells. To overcome the risk of rejection, the company uses cells from O-negative donors—the blood type compatible with all major blood groups.
Since emerging from VentureLabs, part of Flagship Pioneering, Straight Nissen says the Rubius technology has expressed many types of proteins. The company has also developed a way to manufacture cells in bioreactors, which makes the production process scalable. Straight Nissen says Rubius already has the capacity to manufacturing red blood cells for clinical trials.
Two years ago, Rubius’ lead target was phenylketonuria (PKU), a rare inherited disorder in which an amino acid called phenylalanine builds up in the body. A Rubius treatment would engineer red blood cells to carry the enzyme to break down that amino acid. When asked if PKU is still a top priority, Straight Nissen demurred and said that it was part of a broader strategy that now includes other diseases. The technology could have applications in other enzyme replacement therapies, as well as in other diseases, such as cancer and autoimmune disorders, he says. The company’s first studies in humans could start next year.
Flagship supported Rubius’ 2015 launch with $25 million in funding and was among the investors in the latest investment. Straight Nissen said the round was oversubscribed but declined to disclose the names of other investors, other to say they included large institutional investors.