Tome Says PKU is Lead Indication

Rare Daily Staff

Tome Biosciences, the gene editing company that says its technology can insert any genetic sequence of any size at any location in the genome with site-specific precision, said its lead program is in preclinical development to treat the rare metabolic disorder phenylketonuria.

The company, which launched with $210 in backing at the end of 2023, had not previously disclosed the targets of its programs. During a presentation at the American Society of Gene & Cell Therapy annual meeting, it shared preclinical data highlighting its progress in developing its programmable gene insertion (PGI) technology.

The company reported that it achieved therapeutically relevant targeted gene integration and functional protein expression in vivo in non-human primates.

It also demonstrated efficient multiplex editing and integration of large DNA sequences with functional gene expression in iPSC-derived NK cells, a type of white blood cell that destroys infected cells.

Phenylketonuria (PKU) is a rare condition caused by uncontrollable levels of the amino acid phenylalanine (Phe), which can lead to neurocognitive deficits. Despite two approved treatments, approximately 75 percent of patients in the United States remain untreated because they are either unresponsive to current therapies or these options present safety risks. Given that Phe is found in all sources of natural protein, the only option for most patients is a challenging diet virtually free of protein, with supplemental formula requirements for the rest of their lives to try to lower neurotoxic Phe levels.

Tome also showed progress in its lead programs of an integrative gene therapy for phenylketonuria and a CD19/BCMA CAR-iNK for renal autoimmune diseases.

“Our presentations at ASGCT provided a snapshot of the broad capabilities afforded by PGI technologies, from rapid, efficient and multiplex editing of iPSCs and HSCs to targeted integration of functional genes at therapeutically relevant levels in non-human primates,” said John Finn, chief scientific officer of Tome.

Photo: John Finn, chief scientific officer of Tome