Eledon Pharmaceuticals, Inc. (Eledon), is a biotechnology company led by Dr. David-Alexandre C. Gros, its CEO and a 1999 graduate of the Johns Hopkins School of Medicine. Eledon recently announced that two out of the three subjects with Type 1 diabetes treated with Eledon’s drug, tegoprubart, were able to achieve insulin independence after islet cell transplantation between three and six months post-transplant, with the third on the trajectory for insulin independence.
In an interview with The News-Letter, Gros provided a brief history of the company and explained its mission and current work.
“Eledon was founded thanks to patients and patient advocacy. Our drug, tegoprubart, was discovered at the ALS Therapy Development Institute, the world’s largest preclinical ALS research lab. In 2020, with our [Chief Scientific Officer] Dr. Steve Perrin — the inventor of tegoprubart — we founded what is today Eledon,” Gros elaborated. “We did that by taking tegoprubart out of the Institute, putting it into a public company shell, and at the time, we raised about $116 million to enable tegoprubart’s development.”
Gros highlighted the significance of Eledon’s investors, specifically pointing to Breakthrough T1D — a nonprofit organization leading Type 1 diabetes research and advocacy — as well as the families of patients.
“Eledon’s investors include families that have been affected by either ALS, diabetes or end-stage kidney disease. They’ve invested in us not just because they believe we’re a good investment, but because they believe in the difference that we are trying to make,” he said. “That’s very different from your typical biotechnology company — often funded by large institutional funds. We fully recognize that patient connection in everything that we do and are grateful for their support.”
Type 1 diabetes is a condition where the pancreas produces little to no insulin, which prevents the transport of glucose from the blood to the cells and results in elevated blood sugar levels. It currently impacts more than two million Americans. Islet cell transplantation is a developing treatment for patients with Type 1 Diabetes, where islet cells, pancreatic cells that synthesize insulin and control blood sugar levels, are obtained from a donor and are infused into the patient’s liver. Patients take immunosuppressants for the rest of their lives to ensure the body does not reject these islet cells.
Tegoprubart, Eledon’s immunosuppressive drug, is an anti-CD40L antibody that blocks the CD40 ligand from binding to CD40. The CD40L-CD40 interaction plays a key role in amplifying immune responses through multiple mechanisms including T cell regulation and antibody production. In clinical comparisons with tacrolimus, the FDA-approved calcineurin inhibitor standard since 1994, patients treated with tegoprubart demonstrated islet engraftment rates three to five times higher than those observed in patients receiving tacrolimus.
“Historically, drugs that suppress the immune system, like transplant medicines or drugs for autoimmune diseases like arthritis, do so by wiping out the population of white blood cells…Drugs in the past and current standard of care immunosuppression drugs [like tacrolimus] wipe out a part of the immune system,” Gros said.
Tegoprubart, however, differs from the traditional approaches. Tegoprubart is not toxic to white blood cells, and the drug does not wipe out those cells.
“What we’re doing is changing how white blood cells communicate with one another, in particular, T cells, and how they communicate with other cells so that they don’t activate the immune system… Research thus far suggests that this may lead to a safer, more efficient drug,” Gros explained.
Tegoprubart was also used as an immunosuppressant for the first-ever porcine kidney xenotransplantation conducted at Massachusetts General Hospital in March 2024 and the second-ever porcine heart xenotransplantation conducted at the University of Maryland Medical Center in September 2023. Xenotransplantation is seen as a potential method to alleviate the current organ shortage; as of October 2024, more than 100,000 people are on the national transplant waiting list, with 17 people dying each day while waiting for a transplant. Eledon currently has xenotransplant partnerships in countries including US, Europe and Japan.
“Most people would agree that for xenotransplantation to become a reality, we’re going to need to use an anti-CD40L antibody – which is what tegoprubart is... But the lower hanging fruit [to combat the donor organ shortage] is to increase the life of transplanted organs,“ Gros said. “Kidney transplants only survive, on average, 10-15 years. To live a normal life, [younger patients] will need multiple transplants… Each repeat transplant takes up another organ that otherwise would have gone to someone in need and saved their life.”
A side effect of tacrolimus is heart and lung transplant patients often face is kidney problems. A positive dose relationship between tacrolimus concentrations and toxicity in kidneys has been observed in multiple studies. A potential explanation for tacrolimus-caused nephrotoxicity comes from research on cyclosporine, a calcineurin inhibitor immunosuppressant like tacrolimus. This calcineurin inhibitor causes vasoconstriction, the narrowing of blood vessels, specifically the arterioles in the kidneys. In turn, the amount of blood reaching the kidneys decreases, as does the filtered blood, leading to toxin buildup and kidney damage.
“The organ damaging side effects often associated with standard of care immunosuppression drugs [like tacrolimus] are one of the ironies of transplant medicine. Our drug [tegoprubart] was designed not to destroy the kidney and to protect the pancreas, so we expect that there will be fewer repeat kidney transplants, freeing up the organs for other people,” Gros said. “[Transplant patients] have to take an immunosuppressant – we want tegoprubart to be the new cornerstone standard of care that’s used for every transplanted organ — regardless of organ source.”
Currently, tegoprubart’s role in preventing rejection in kidney transplant patients is being studied in three clinical trials, including a Phase 2 BESTOW trial consisting of 120 subjects. The trial aims to analyze the state of kidney transplantation patients who have been treated with tegoprubart compared to patients who have been treated with tacrolimus a year post-transplant. The study has clinical sites at Johns Hopkins University.
Beyond Eledon’s collaboration with Johns Hopkins University, Gros reflected on his time as a medical student at the Johns Hopkins School of Medicine.
“Everything I do goes back to my time at Hopkins. My first surgeries, which included liver and kidney transplantations, and then, the research I did throughout my four years in med school. The research changes, but the ability to comprehend the scientific research is the same,” he reflected.
