Unum Therapeutics has completed a $65 million Series B financing. New investor New Leaf Venture Partners led the round. The company was launched by Fidelity Biosciences, Atlas Venture and Sanofi-Genzyme BioVentures with a $12 million Series A financing in October 2014.
Unum is developing the antibody-coupled T-cell receptor (ACTR) technology developed by Dr. Dario Campana. At St. Jude Children’s Research Hospital, Campana previously created the anti-CD19 CAR-T that Dr. Carl June at the University of Pennsylvania took into clinical trials.
ACTR is a chimeric protein that combines the Fc receptor (CD16) with the signal transduction domains (4-1BB/CD3ζ). Engineered T cells bearing the ACTR can bind to a monoclonal antibody which then acts as a bridge to the tumor cells.
In contrast to other CAR-T therapies that hit a single target, Unum’s approach is not restricted by antigens. In other words, one ACTR therapy can be used in combination with a variety of antibodies like Rituxan or Herceptin to attack many different cancers.
In addition, the activity of CAR-T therapy can be turned up or down by adjusting antibody dose. Furthermore, Unum uses mRNA instead of a virus to modify T cells. The modified cells are disarmed in about a week. These features may avoid safety problems that were commonly reported in CAR-T trials.
Unum is testing its lead ACTR therapy, ATTCK20, in combination with Rituxan in a Phase I trial. The new money gives the company enough fuel to complete a series of proof-of-concept studies.