CAMBRIDGE, MA, USA I March 11, 2019 I Rubius Therapeutics, Inc. (Nasdaq:RUBY), a biopharmaceutical company that is generating red blood cells and bioengineering them into an entirely new class of cellular medicines, today announced that the U.S. Food and Drug Administration (FDA) has cleared the company’s Investigational New Drug (IND) application for RTX-134, an allogeneic, off-the-shelf cellular therapy for the potential treatment of patients with phenylketonuria (PKU). The Phase 1b clinical trial is expected to be the first-ever clinical investigation of genetically engineered red blood cells. The Company plans to begin enrollment during the second quarter of 2019, with initial clinical data expected during the second half of 2019.

“The clearance of the RTX-134 IND is a historic event for Rubius as we advance one step closer to treating patients with phenylketonuria, an inherited metabolic disorder that is characterized by the body’s inability to metabolize the essential dietary amino acid, phenylalanine. PKU is a devastating disease that when not properly treated can cause intellectual disability, delayed development, impaired cognitive function and, in some cases, irreversible brain damage,” said Pablo J. Cagnoni, M.D., chief executive officer of Rubius. “Our goal with RTX-134 is to overcome this brain-threatening metabolic disorder by providing patients with a safe and effective treatment option to lower phenylalanine levels via infrequent administration, allowing people with PKU to return to a normal diet.”

RTX-134 is a Red Cell Therapeutic™ (RCT) product candidate that is genetically engineered to express the enzyme phenylalanine ammonia lyase (PAL) inside the cell. RTX-134 is designed to circulate in the blood stream and degrade toxic levels of phenylalanine that accumulate due to a deficiency in the phenylalanine hydroxylase (PAH) enzyme. Compared to current therapeutic interventions, RTX-134 may have a more sustained treatment effect given the 120-day circulating time of red blood cells and may have a lower incidence of immune-driven adverse events, including the formation of neutralizing antibodies to the therapeutic enzyme, which often results in a reduction in efficacy. As a result, RTX-134 may provide a more efficacious and convenient treatment option to patients.

About the RTX-134-01 Phase 1b Clinical Trial
The Phase 1b clinical trial is an open-label, single-dose safety, tolerability and pharmacokinetics study of RTX-134 in adults with PKU. The primary objectives of the study are to evaluate preliminary safety, longevity of the RTX-134 cells in circulation, to obtain proof-of-mechanism as measured by production of trans-cinnamic acid (the byproduct of PAL) and select a preliminary dose and schedule. Rubius expects to report initial data during the second half of 2019. Following FDA review of the data from the Phase 1b study, the Company plans to investigate multi-dose administration of RTX-134 to further evaluate safety and efficacy.

About Rubius Therapeutics
Rubius Therapeutics is a biopharmaceutical company that is generating red blood cells and bioengineering them into an entirely new class of cellular medicines. The Company’s proprietary RED PLATFORM® is designed to genetically engineer and culture Red Cell Therapeutics™ that are selective, potent, ready-to-use allogeneic cellular therapies. Rubius is leveraging three distinct therapeutic modalities — cellular shielding, potent cell-cell interaction and tolerance induction for the potential treatment of rare enzyme disorders, cancer and autoimmune diseases. For more information, visit or follow us on Twitter and LinkedIn.

SOURCE: Rubius Therapeutics