Typewriter raises $56 million to generate CAR-T cells directly in the body
Typewriter raises $56 million to generate CAR-T cells directly in the body
On September 2, Typewriter Therapeutics emerged from stealth with a $56 million Series A round. The biotechnology company is developing a lipid nanoparticle therapy containing two RNAs that is intended to equip a patient’s T cells with a receptor that recognizes a selected target. Typewriter reports proof of concept in humanized mice, which have components of a human immune system, and plans to begin its first studies in nonhuman primates by the end of 2026.
CAR-T cells are immune T cells engineered with an added receptor that recognizes a selected target, such as a molecule on a tumor. These cells are currently produced outside the body in most cases. Clinicians collect a patient’s cells, modify them in a laboratory, and return them to the patient. Growing demand for CAR-T therapies made from a patient’s own cells is constrained by the need for separate manufacturing for each person, including production facilities, quality control, shipping, and coordination with the clinic. Typewriter aims to insert the gene encoding the receptor directly into the patient’s T cells.
The system is based on R2, a retrotransposon that copies its RNA into DNA. In a 2019 study, an R2Ol variant from medaka fish inserted genetic material into a specified sequence within human 28S ribosomal DNA. This is a repetitive region of the genome associated with the assembly of ribosomes, the cellular machinery that produces proteins. In that experiment, the researchers delivered R2Ol using an adenovirus and supplied the template gene as a circular DNA molecule to test targeted insertion.
According to the company’s description of its technology, it packages two RNAs in a lipid nanoparticle. One is messenger RNA containing the instructions for producing the R2 protein, while the other carries the therapeutic gene. The R2 protein is intended to bind the second RNA, nick one DNA strand at the 28S site, and copy the gene into that location. The company identifies in vivo CAR-T therapy and inherited liver diseases as its initial areas of interest. The funding is intended to support the selection of its first development program.