As it gears up to move its lead cell therapy into phase 3, Regenerex has closed a $100 million financing, built out its leadership team and renamed itself Talaris Therapeutics after the winged sandals worn by the Greek messenger god Hermes.
Talaris is working on cell therapies that could one day eliminate the need for lifelong immunosuppression in patients who receive organ transplants. Its work is based on technology developed by Dr. Suzanne Ildstad, a transplant surgeon who saw firsthand the challenges and side effects borne by transplant patients.
“Transplants sound easy, but patients need to take up to 25 pills a day,” she said. And, as if juggling many medications isn’t hard enough for patients, they also have to contend with side effects from the drugs, such as high blood pressure, diabetes, high cholesterol and infections that could be life-threatening, she told FierceBiotech.
Talaris’ cell therapies are designed to give transplant patients immune tolerance—that means making the body “see” a transplanted organ as part of itself rather than as a foreign body that it should reject. Its lead program is being developed for patients receiving a kidney transplant from a living donor. The treatment, known as FCR001, is based on stem cells taken from the same person who donated the kidney.
“The goal here is—if this therapy works—then a kidney transplant recipient essentially will have two immune systems,” said Scott Requadt, the newly appointed CEO of Talaris. One of the immune systems is their own, while the second is made up of immune cells produced when the donor stem cells take root in the patient’s bone marrow, he said.
Talaris calls this dual system a “chimeric immune system.” It’s a concept that has been shown to work in mice for more than 60 years but hasn’t been reproduced in humans until recently, Requadt said.
After seeing encouraging phase 2 results, Talaris is planning to move FCR001 into phase 3 later this year. The $100 million financing, drawn from Blackstone Life Sciences, Longitude Capital and Qiming Venture Partners USA, will propel FCR001 into later-stage studies.
The phase 2 study treated 37 patients who received a living kidney donation with FCR001. Twenty-six of them—70%—were able to stop taking their immunosuppressive meds. And it worked in patients and donors who weren’t a perfect match, which could lead to more people being able to donate kidneys.
The patients who managed to get off immunosuppressive meds were still off them, on average, five years later. And some of them were still going strong after 10 years.
With data in hand, Talaris is considering other possibilities for its technology. It currently uses it in new transplant patients, but thinks it might be useful in patients who have already undergone the procedure.
“For patients who have previously received a living donor kidney transplant, we could go back to the original kidney donor, get them to donate stem cells and see if we can induce tolerance in the recipient after the fact,” Ildstadt said.
It could even potentially work in patients who receive organs from deceased donors. “We’ve already done R&D on that—the best source of bone marrow stem cells in deceased donors is the vertebral column [the spine],” Ildstadt said. The idea would be to extract stem cells from the donor’s spine and then freeze them for later treatment.
“People who need a liver or heart transplant are quite sick, so we couldn’t do the treatment immediately after a solid organ transplant,” she said. Talaris has already tried freezing stem cells in the living donor kidney transplant study.
“Logistically, it is very doable,” Ildstadt said.
Transplants aside, the chimeric immune system could also be used to treat autoimmune and immune-mediated diseases.
“If you can train an immune system to see a donated organ as self, then the same technology could also be used to reset the recipient’s immune system to no longer see itself as foreign, which is what you see in autoimmune disease,” Requadt said.
Talaris is working on some autoimmune conditions with plans to start a phase 2 proof-of-concept study in one of them in 2020.
Editor's note: This story was updated to clarify the average amount of time patients in the phase 2 study had been followed, and that the patients followed for 10 years continued to stay off immunosuppressive drugs.