Consider This from NPR - In U.S., Over 100,000 Await Organ Transplants. Are Pig Organs The Solution?

Episode Date: April 3, 2024

The recent transplant of a genetically modified pig kidney into a living human raises hopes that lives will no longer depend on the availability of human donor organs.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

Today we recognize a truly monumental milestone, one we hope is a giant leap forward. Dr. David Brown of Boston's Massachusetts General Hospital. Advancing transplant surgery to provide viable, readily available organs to patients who so desperately need them. For the first time, a genetically modified pig's kidney was transplanted successfully into a living person. This was a couple of weeks ago. The patient, Richard Slayman, is 62 years old. He's recovering well so far, expected to be discharged from the hospital today. The new kidney inside Slayman comes from a cloned pig that was genetically modified nearby in Massachusetts by a company named eGenesis. It's one of many biotech companies

racing to develop a supply of cloned pigs whose DNA has been genetically altered so their organs will not be rejected by the human body or cause other complications. NPR health correspondent Rob Stein recently became the first journalist to tour one of the research farms where pigs are being bred, cloned, and gene edited in the hope of providing organs to people who need life-saving transplants. We have 22 buildings and a census of pigs, around 300 pigs, all for research purposes. That is David Ayers, who runs Revivacor, a biotech company in southwest Virginia's Blue Ridge Mountains. Before meeting the pigs, Ayers had our colleague Rob change into hospital scrubs. Their truck had to be disinfected.

And their boots. Finally, after several rounds of decontamination, Rob got to meet the little guys. So those are genetically modified piglets? Yes, all these piglets are genetically modified. Wow. Each of these piglets was genetically modified by fusing edited pig skin cells with pig eggs. Two zaps of electricity turn them into cloned pig embryos that are implanted into the wombs of adult pigs. Then, four months later, cloned piglets were born. If you want, you know, you can hold one.

Yeah, that'd be great. You'll be surprised at how dense they are. Oh, that's okay. Yeah, that's okay. You'll be surprised at how dense they are. Aww. That's okay. Yeah. That's okay. You're so cute. Each of these cute piglets has 10 identical genetic modifications designed to make sure their organs do not get too big for a human

and won't cause blood clots or be rejected by the human immune system. Those litters will allow us to do multiple organ procurements from one animal. For example, we can get two kidneys and a heart, and the holy grail would be to get all the organs that you need for human transplant from one donor animal. That could change the game in the U.S., where some 100,000 people are on the waiting list for transplants. But before we get carried away, there is still a lot to be learned about transplants from cloned pigs to humans. Before Richard Sleeman's kidney transplant, two men received pig hearts. Both died a few weeks

after their procedures. Some scientists worry that even with careful gene editing, there's a chance of pig viruses accidentally being passed to humans. And ethicists, they have all kinds of concerns about these transplants. I worry that we are using these individuals in these very speculative experiments. You want to worry about really vulnerable patients who are really desperate, who perhaps are being given an offer they can't refuse. Consider this. Cloned pigs could end the long-standing organ shortage problem in the U.S. But how safe and how permanent a solution are pig to human transplants? And what are the medical ethics of such procedures?

From NPR, I'm Mary Louise Kelly. It's Consider This from NPR. Like a page out of a sci-fi novel, a man in Massachusetts is now walking around with a kidney from a cloned pig. Richard Sleeman recently became the first live human to receive a kidney from a genetically modified pig. For many, cloned pigs are the dream solution to organ shortages. More than 100,000 people in the U.S. need an organ transplant. 17 people a day die without getting one because there are just not enough organs available. David Ayers runs a biotech company that breeds the animals.

It's exciting. We've been working on this for more than 20 years, and it's no longer a science fiction experiment. It's actually reality. But ethicists point to the many, many unanswered questions. Like, what if pig viruses are accidentally transmitted to humans? Is it right to breed pigs just to slaughter them and harvest their organs? And what are the implications of genetically engineering animals? Well, Michael Guzmano has spent a lot of time thinking on such questions. He's a professor of health policy at Lehigh University. Professor Guzmano, welcome. Hello. How are you?

I am well, thank you. I know we're going to get to the concerns and all the questions, but let's start with the promise of this. How big a deal is this transplant, a kidney from a clone pig? I think it's a very big deal. It is something that's been worked on for decades. And until the 1990s, a lot of the research was halted because of concerns about viral transmission. And with the development of gene editing tools, it has really picked up steam quite a bit. This is a huge step forward potentially, but it's a one-off compassionate use case. So we're going to need a lot more information to know whether it actually represents a solution. But the organ shortage is enormous, so we need to do something. Yeah. You just said a number of things I want to follow up on.

The first is just to this point of whether pig organs are indeed the dream solution. They could end the organ shortage problem. Some scientists say yes. You, I'm already gathering, are more the dream solution. They could end the organ shortage problem. Some scientists say yes. You, I'm already gathering, are more cautiously optimistic. Why? Well, first of all, just technically, we don't know whether this is going to work. So far, the news from this one patient is terrific. The kidney seems to be functioning.

But it's been a few weeks, right? We want to make sure that the kidney is going to last much longer than that. And there's a limit to what you can generalize, whether you're talking about the function of the kidney transplant or any downside risks, whether it's zoonotic disease infection or other problems that may come about, that's really going to require a much larger clinical trial. And when we speak about this as a possible solution, is the hope that pig kidneys or other organs could serve as a lifelong replacement for a human organ? Or at this point, at least, does it feel more like a temporary solution while a patient waits for a human organ to

become available? I think the honest answer is we don't know. I think the hope is that it would become a long-term solution, something that works as well as a human kidney and would last as long as a human kidney. But I've heard a number of xeno scientists who have said that it's possible that this could just be a kind of a bridge, right? So if you had a graft that could last six months or a year and function reasonably well, that could take people off of dialysis. And if you can remove someone from dialysis for a full year, that alone would improve their health and their well-being. And it's possible that that would allow them to sort of last longer until a human kidney is available.

So let's go through some of the questions being raised. One, that question of whether pig viruses might accidentally be transmitted. Our correspondent, NPR correspondent Rob Stein, went to a farm. He saw where these genetically modified pigs are being bred. He described how careful the researchers are about cleanliness, how the pigs are genetically modified in part to remove potentially harmful viruses, and yet it's a risk. How real a risk? Well, the big concern, I think, is unknown unknowns, if you will. If we have knowledge of zoonotic infection, it is now possible with genetic modifications to knock that out so that you really minimize the risk of transmission.

The question is, are there zoonotic viruses that we don't know about that haven't been addressed by the genetic modifications? Most of the physicians I've interviewed about this suggest that they think the risk is relatively low, but they're not willing to rule it out entirely. So that's the big unknown that we need to explore with more research. Yeah. What about the animal welfare concern? Why are we breeding pigs just to slaughter them so we can harvest their organs? Right. I think the positive response is, as one patient I interviewed suggested, we breed pigs and slaughter pigs so that people can eat their BLTs. Why wouldn't we do it to save human life? I think the counter to that is we shouldn't be doing

the former, and that doesn't justify the latter. What we ought to be doing is exploring other alternatives, whether it is mechanical dialysis that has been miniaturized or whether it's finding creative solutions to increase the number of people who are willing to become live donors. You used a term a moment ago, compassionate use trials, and I want you to explain that. What does it mean? What is the concern? Well, one important thing to note is that it's not a trial. So it is a compassionate use experiment. It is a one-off use of an emerging technology that has not yet been approved by the FDA for routine clinical use. In the case of the patient who just received the pig kidney, this person had run out of other options and was likely to die. And so the thought was we should give permission for this to take

place, even though we don't have data from clinical trials. My concern about that and the difference between this and a clinical trial is these are one-time uses, and therefore there's a limited amount of information that you're going to learn. So where do you fall, understanding there's a huge range of views in the scientific community on how much research needs to be done to feel more comfortable with all this. Where do you fall on that question? I think we're rapidly getting to a point where we probably have learned as much as we're going to move forward, I would prefer the FDA authorize a first in human clinical trial. Because if we're going to start doing this and actually placing the genetically modified pig kidneys in human beings, I would like to do it in a context where we're doing it systematically.

We have selection criteria for who receives the organ, and we're gathering better information about whether it will work. If you think back to the two pig heart transplantations, both of those patients died in about two months. I don't think you can conclude from that that, you know, pig hearts don't function. These were both incredibly sick human beings who were very frail. They may not have worked simply because of their underlying health conditions.

And so we need better scientific information before we invest more in this kind of work. You're making me think there's the question of clinical trials and what kind of scientific data we need to gather. Also, just the importance of a public conversation about this, about educating people on the risks and rewards. Where does that conversation stand? I think it's in a nascent stage. You can find a number of early public opinion polls where people are asked about this.

Recently, there was an effort, I believe last year in Germany, to do a form of public deliberation, which resulted in cautious support for doing this. And so I do suspect that the public would support moving forward on this. But I think given the number of big issues that it raises around animal welfare, around zoonotic disease, it's important for the public to have a trust that this is being done for the right reasons and in the right way. Michael Guzmano of Lehigh University, where he is a professor of health policy. Thank you so much for chatting this through with us. Thank you. My pleasure. This episode was produced by Janaki Mehta with audio engineering by David Greenberg and Stu Rushfield. It was edited by Jeanette Woods and Scott Hensley.

It featured reporting from Rob Stein. Our executive producer is Sammy Yenigan. It's Consider This. From NPR, I'm Mary Louise Kelly.