Beyond cold storage: Technology designed to keep organs warm, helps liver transplant patients in key study
Since the 1960s, cold storage emerged as the preferred method for organ preservation for transplantation, but it didn’t tick all the boxes — limitations such as the risk of early graft dysfunction still contribute to chronic complications. So an upgrade was in order. Instead of flushing and preserving the procured organ at roughly freezing temperatures, new technology actually keeps the organs warm and toasty for transplantation in a bid to improve organ accessibility and improve transplantation outcomes.
The technology, pioneered by Andover, Massachusetts-based TransMedics, approved for use by the FDA for lung preservation, is under regulatory review for the heart — and is being tested for the liver. On Tuesday, the developer unveiled late-stage data that showed its product, called the Organ Care System (OCS) System, lowered the incidence of early allograft dysfunction (EAD) — an initial poor function of the transplanted liver that typically portends poor allograft and patient survival.
The 300-patient trial, christened PROTECT, assessed the impact of the OCS system on preserving and assessing donor livers intended for transplantation — 153 patients were transplanted with the OCS Liver and 147 patients were on the control group, which employed cold storage methods.
The primary effectiveness endpoint was the incidence of EAD in the first 7 days following transplant procedures, and that was met: 17.3% for OCS versus 30.5% for control (p=0.009). The main safety goal, the average number of liver graft-related serious adverse events per patient measured over 30 days following transplantation, was also achieved 0.046 for the OCS group, compared to 0.075 in the control arm (p<0.0001).
Secondary efficacy endpoints, including a significantly lower incidence of ischemic cholangiopathy complications at 6 months post-transplantation, were also met.
“To our knowledge, these results from the OCS Liver PROTECT trial represent the first time a new technology or therapy has had a positive impact on both EAD and ischemic cholangiopathy in liver transplantation,” said Malcolm MacConmara, the trial’s co-investigator and director of the organ research lab at UT Southwestern Medical Center. “If approved, this would safely expand the utilization of donor livers and significantly increase the number of livers available for life-saving transplantation.”
For now, the OCS system is approved for lung preservation — it is designed to reduce the time during which the lungs lack blood and oxygen support outside of the body. It includes a portable enclosure with mechanical and electrical components used to warm, ventilate and perfuse the lungs — as well as a lung preservation solution combined with packed red blood cells. The transplant team can also monitor and assess the donor lungs while they are being perfused before transplantation.
Initially it was sanctioned for use in only standard-criteria donor lungs, but last year the FDA expanded its use in donor lung pairs initially considered unacceptable for transplantation based on limitations of cold storage preservation, for example for patients that are geographically distant.