During the 2026 BIO International convention in San Diego, GEN sat down with Aki Ko, CEO of Elixirgen Therapeutics, to discuss the company’s multi-platform technology development efforts. The company, which was founded in 2017, is developing what it believes are breakthrough technologies that target telomere biology disorders (TBD) and aging as well as mRNA-based therapies.
Its therapy for addressing telomere biology disorders, based on its proprietary ZSCAN4 approach, is the furthest to the clinic. The biotech company will also target other aging-related diseases with the technology. Meanwhile, its efforts in the mRNA space are currently focused on Duchenne Muscular Dystrophy (DMD), although there are plans to pursue other targets there as well.
Ko founded the company with CSO Minoru Ko, MD, PhD, in 2017. Elixirgen’s 15 employees are based in Baltimore in its office space in the Johns Hopkins Medical campus, although there is no affiliation with the university. This location offers some advantages to the company, according to Ko. Specifically, “we have a wet lab and an animal lab” that has “helped us go from in vivo to in vitro very quickly to test concepts or optimize formulations and things like that.”
Recently, Elixirgen announced an option agreement with Japan’s Nippon Shinyaku focused on DMD. Under the terms of the agreement, Elixirgen will be responsible for the development of an asset dubbed EXG-7001, a locally administered, full-length dystrophin mRNA therapeutic that is currently in preclinical development for the treatment of DMD.
As part of the deal, Nippon Shinyaku will provide funding for the developmental costs of the therapy. Meanwhile, Elixirgen will receive an upfront payment and is eligible to receive additional development and sales-based milestone payments if the option were to be exercised. Also, Nippon Shinyaku may obtain exclusive worldwide rights to commercialize EXG-7001.
“Current approaches for treating DMD focus on delivering or restoring an incomplete dystrophin protein, and there still remains a significant unmet need for a therapy that can successfully deliver a full-length dystrophin protein,” Ko said in comments about the announcement. “By design, EXG-7001 has the potential to deliver the full-length, complete dystrophin protein that is missing in DMD patients, regardless of their genetic mutation.”
EXG-7001 leverages one of Elixirgen’s core technologies. The company has developed a platform for delivering mRNA-based therapies that it claims addresses the major delivery limitations of current methods. “The key features are that it is a lipid nanoparticle-free, localized mRNA therapeutics platform,” Ko explained to GEN. With this approach, “we’re avoiding some of the complications of gene therapies and delivering genes systemically by going local” and avoiding liver accumulation, which remains “a big issue” for mRNA therapeutics.
The system has two components. The first component, called RNA tether, is designed to ensure that the RNA stays in the tissue that is injected without migrating to the liver. The second component is the mRNA cargo itself, which the company calls Bobcat® mRNA. Though the lead indication for this technology is DMD, there are other diseases involving large genes that the company could target.
“We’re able to express the full length protein as mRNA as a single strand” and “it stays where you administer it, which is kind of unusual,” Ko said. Combining RNA tether and Bobcat makes it possible to express large genes and localize them to target tissues even without accumulation in the liver. Preclinical data has demonstrated its effectiveness in mice with no safety concerns associated with administration or treatment. “A full length dystrophin being given to kind of key muscles could potentially change quality of life,” particularly for the non-ambulatory population, Ko said.
Beyond EXG-7001, Elixigen has other candidates in its pipeline that are much closer to the clinic. Its lead candidate is currently in Phase I/II testing at Cincinnati Children’s Hospital Medical Center. This is an ex vivo cell therapy based on the company’s ZSCAN4 technology, which is designed to extend the telomeres of stem cells in “a controlled way” using a telomerase-independent mechanism. EXG-34217 is comprised of autologous CD34+ hematopoietic stem cells that have been treated ex vivo with EXG-001, a non-integrating, non-transmissible, temperature-sensitive Sendai virus vector encoding human ZSCAN4.
The features of that technology were identified by the company’s CSO and his team while he worked at the National Institutes of Health’s National Institute on Aging. In 2024, the U.S. Food and Drug Administration granted Rare Pediatric Disease Designation to the treatment, dubbed EXG-34217, for the treatment of patients with dyskeratosis congenita and related telomere biology disorders.
“Telomeres obviously have a relationship with aging, and there are in fact genetic diseases associated with short telomeres and telomerase mutations,” CEO Ko told GEN at BIO. People with TBDs are “born with shorter telomeres typically, but also have a mutation in their telomerase so they are not necessarily maintaining them either.” The result is a type of premature aging, so conditions like bone marrow failure and cytopenia happen earlier in the life of the patient. In fact, “bone marrow failure is one of the largest issues” affecting both adults and young children, CEO Ko said.
One treatment option in these cases is allogeneic hematopoietic stem cell transplantation (HSCT), he continued. However, people with short telomeres have more fragile genomes that are less resistant to chemotherapy and radiotherapy and are at greater risk of cancer even after HSCT treatment. In an ideal scenario, it would be possible to postpone or avoid HSCT for these patients, and the company’s ZSCAN4-based therapy could make it possible to do that.
The treatment is currently being tested in adult and pediatric patients in Cincinnati. “We started in adults because this is first-in-human,” but the disease is also very severe in children, Ko said. “Our target ultimately is to make sure as many people with TBDs can get this if they need it.” Early clinical results published in 2025 in a paper in NEJM Evidence show durable telomere extension overall with no treatment-related safety concerns observed over a 24-month and 5-month period after infusion. The trial has been going on for some time, and “we have a lot of longer-term data now” and are “looking toward potential accelerated approval.”
But targeting TBDs is just one indication. “Short telomeres manifest in many different ways,” Ko said. Other potential targets for the company’s technology are aging-related diseases, including things like idiopathic pulmonary fibrosis.
To date, Elixirgen has raised roughly $34 million from existing investors.
