United Therapeutics’ Liver Assist Product Earns FDA Regenerative Medicine Advanced Therapy Designation

The U.S. Food and Drug Administration (FDA) has granted Regenerative Medicine Advanced Therapy (RMAT) designation to United Therapeutics Corporation’s investigational external liver assist product, miroliverELAP.

Developed by Miromatrix Medical Inc., a wholly owned United Therapeutics subsidiary, miroliverELAP consists of an external blood circuit and a single-use bioengineered liver, maintained outside the human body, to provide temporary liver support for acute liver failure (ALF) patients. The bioengineered liver is manufactured by seeding a decellularized porcine liver scaffold with allogeneic human endothelial cells and human liver cells isolated from donated human livers. The donated human livers are not suitable for transplant and are provided by organ procurement organizations.

Earlier this year, United Therapeutics announced positive results from its phase 1 study of miroliverELAP in patients with acute forms of liver failure, acute-on-chronic liver failure, and severe acute alcoholic hepatitis, collectively called acute liver failure. Full study results will be published in the second half of 2026. miroliverELAP is investigational and is not approved for any use in any country.

In addition to miroliverELAP, United Therapeutics and Miromatrix are developing mirokidney, a fully transplantable bioengineered kidney, using the same decellularization and seeding technology found in miroliverELAP.

The FDA’s RMAT designation is a specialized program to help accelerate the development and regulatory review of promising regenerative medicine therapies that target serious or life-threatening diseases with unmet medical needs while maintaining rigorous safety and efficacy standards. To receive RMAT designation, a therapy must demonstrate preliminary clinical evidence of potential efficacy in treating, modifying, reversing, or curing such conditions. Once designated, sponsors receive intensive FDA guidance throughout the development process, including advice on efficient study design, surrogate endpoints, and pathways to accelerated approval. The designation also provides significant regulatory advantages such as eligibility for priority review, rolling review of Biologics License Application materials, and enhanced organizational commitment from the FDA to expedite the overall development and approval timeline.

“Receiving this designation from the FDA highlights both the critical unmet need we are addressing and the promising potential of miroliverELAP as a novel therapeutic option,” Miromatrix President Jeff Ross, Ph.D., said. “We look forward to continuing our collaborative exchange with the FDA as we advance the clinical development of miroliverELAP for patients with acute liver failure.”

A condition that affects thousands of patients annually, ALF is characterized by a rapid loss of liver function in a matter of days or weeks. Approximately 45% of ALF patients experience spontaneous recovery, while 25% receive a liver transplant, the only effective ALF treatment. Approximately 30% of ALF patients die because they are ineligible for a liver transplant or are unable to receive one in time due to the disease’s rapid onset and the shortage of transplantable organs.¹

United Therapeutics’ organ and organ alternative manufacturing efforts consist of three platforms— xenotransplantation, allogeneic regenerative medicine, and autologous regenerative medicine—encompassing four different organs: hearts, kidneys, livers, and lungs. These programs aim to address the ongoing shortage of transplantable organs for patients with end-stage organ disease.

Founded by CEO Martine Rothblatt to discover a cure for her daughter’s pulmonary arterial hypertension, United Therapeutics transforms rare disease treatment and pioneers alternatives to expand the transplantable organ supply. From its therapies to its manufactured organs, the company moves quickly from scientific theory to practical technologies that can save lives.

Reference
¹ Lee, W. M., Squires, R. H., Jr, Nyberg, S. L., Doo, E., & Hoofnagle, J. H. (2008). Acute liver failure: Summary of a workshop. Hepatology (Baltimore, Md.), 47(4), 1401–1415. https://doi.org/10.1002/hep.22177