Gene Writing Technology Company Tessera Therapeutics Emerges from Stealth

Rare Daily Staff

Flagship Pioneering unveiled Tessera Therapeutics, a new company that seeks to treat diseases at their source by writing therapeutic messages into the genome.

Tessera said its Gene Writing platform addresses key limitations of gene therapy and gene editing. Gene Writing technology can alter the genome by efficiently inserting genes and exons, introducing small insertions and deletions, or changing single or multiple DNA base pairs.

The technology could enable cures for diseases that arise from errors in the genome, including monogenic disorders. It could also allow precise gene regulation in other diseases such as neurodegenerative diseases, autoimmune disorders, and metabolic diseases.

“While profound advancements in genetic medicine over the last two decades had therapeutic promise for many previously untreatable diseases, the intrinsic properties of existing gene therapy and editing have significant shortcomings that limit their benefits to patients,” says Noubar Afeyan, founder and CEO of Flagship Pioneering and chairman of Tessera Therapeutics. “Our scientists have invented a new technology, called Gene Writing, that has the ability to write therapeutic messages into the genomes of somatic cells. We created Tessera to pioneer its applications for medicine. However, the breakthrough is broad and could be applied to many different genomes from humans to plants to microorganisms.”

Geoffrey von Maltzahn, an MIT-trained biological engineer; Jacob Rubens, an MIT-trained synthetic biologist; and other scientists at Flagship Labs, the enterprise’s innovation foundry, co-founded Tessera in 2018 to create a platform that could design, make, and launch Gene Writing medicines. A general partner at Flagship Pioneering, von Maltzahn is CEO of Tessera. He has co-founded numerous biotechnology companies, including Sana Biotechnology, Indigo Agriculture, Kaleido Biosciences, Seres Therapeutics, and Axcella Health.

Mobile genetic elements served as the inspiration for Gene Writing. The first mobile genetic element was discovered by Barbara McClintock, who won the 1983 Nobel Prize for revealing the mobile nature of genes. Mobile genetic elements code for the machinery to move or copy themselves into a new location in the genome, and they have been selected over billions of years to autonomously and efficiently “write” their DNA into new genomic sites. Today, mobile genetic elements are among the most abundant and ubiquitous genes in nature.

Over the past two years, Tessera has been mining genomes to discover novel mobile genetic elements and engineering them to create Gene Writing technology. Tessera’s Gene Writers write therapeutic messages into the genome using RNA or DNA templates. RNA-based Gene Writing uses an RNA template and Gene Writer protein to either write a new gene into the genome or guide the rewriting of a pre-existing genomic sequence to make a small substitution, insertion, or deletion. DNA-based Gene Writing uses a DNA template to write a new gene into the genome.

The company said the approach holds the potential to overcome the limitations of current genetic medicine approaches by efficiently writing small and large alterations to the genome of somatic cells with minimal reliance upon host DNA repair pathways, unlike nuclease-based gene editing technologies.

It also permanently adds new DNA to dividing cells, unlike AAV-based gene therapy technologies, writes new DNA sequences into the genome by delivering only RNA, and allows repeated administration of treatments to patients in order to dose genetic medicines to effect, which is not possible with current gene therapies.

Tessera has licensed Flagship Pioneering’s intellectual property estate, which was begun in 2018 with seminal patent filings supporting both RNA and DNA Gene Writing technologies.