Saving lives with pig livers: FDA approves new trial with a spin on an old treatment

Another promising medical trial that could save lives thanks to genetically modified pigs: The FDA has given a select group of companies permission to use modified pig livers as a dialysis-like treatment for people with liver failure.

The process would involve circulating a patient’s blood through the pig liver to help clean the blood of contaminants, excess fluids and waste products to improve or stabilize the health of a patient. The clinical trial would include up to 20 patients who don’t qualify for a liver transplant.

UNOS Chief Medical Officer and former liver transplant surgeon Dr. Andrew Klein says this new advancement is based on a treatment that was first used in the 1970s called xenoperfusion. He spoke recently about what this new FDA trial could mean for saving lives.

How does this compare to a kidney dialysis machine?

Dr. Klein: One of the things that distinguishes a liver transplant from a kidney transplant, which happens more frequently, is in most cases with kidney failure, there are other therapies which can take over the kidney’s function for a period of time, such as dialysis. You don’t really have anything that could take over liver function aside from a new liver. That’s what this new development is trying to become, a sort of dialysis function for people experiencing liver failure.

Do you have experience with xenoperfusion?

Dr. Klein: In 1993 or 1994, I had a patient at John’s Hopkins, a woman who had acute liver failure, was comatose, and was listed as a candidate for a liver transplant. We didn’t have an organ available, but I had a young surgeon working with me who recalled xenoperfusion from the 1970’s as a viable potential treatment for this patient.

So, we got in touch with a farm that housed pigs in an appropriate way for research and went through a whole process. We got consent, procured a liver from the pig, brought it up to the ICU and started the process of perfusing the patient’s blood through the pig liver and then returning it to the patient.

Within 20 minutes, the patient woke up out of her coma and she improved clinically for a number of hours. Eventually the pig liver deteriorated but the good news is we got extra time to find a liver transplant for her. She was transplanted with a donated (human) liver, and she survived and went home.

So, this treatment is not entirely new, but what probably makes it novel and perhaps more durable is the fact that they’re using genetically modified pigs.

How could this be applied to patients today?

Dr. Klein: Two applications come to mind immediately. It could serve as a bridge to transplant, buying a patient time while transplant teams wait for a viable donated organ to become available. It could also be used as a standalone treatment that makes transplantation not necessary, giving the patient’s liver time to regenerate a certain amount and resume functions.

The companies running the FDA trial will need to determine what functions will be restored by this dialysis, will the treatment act as a liver cleanse, removing the body of toxins and waste products, and/or will it restore synthetic functions, such as resupplying the body with substances livers normally produce? I am really intrigued by this second potential application; it could be something that saves someone from being on the transplant waitlist entirely.

Positive results from this FDA trial could mean another step towards saving the lives of patients experiencing organ failure. Read how UNOS is building technology to connect patients with lifesaving organs and how else doctors are using genetically modified animals to save lives.