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Could cloned pigs solve the human organ shortage?


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 Slayman recently became the first live human to receive a kidney from a genetically modified pig. He was released from the hospital earlier this week. Now, for many, cloned pigs are the dream solution to organ shortages. More than 100,000 people in the U.S. need an organ transplant. Seventeen people die every day without getting one because there just aren't enough organs available. David Ayares runs a biotech company that breeds the animals.

DAVID AYARES: 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.

KELLY: 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 Gusmano has spent a lot of time thinking on such questions. He's a professor of health policy at Lehigh University. Hi there, Professor Gusmano.

MICHAEL GUSMANO: Hello. How are you?

KELLY: 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 cloned pig?

GUSMANO: Well, 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.

KELLY: 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 cautiously optimistic. Why?

GUSMANO: 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, 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.

KELLY: 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?

GUSMANO: 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 xenoscientists (ph) who have said that it's possible that this could just be a kind of a bridge, right? And 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.

KELLY: So let's go through some of the questions being raised - one, the animal welfare concern. The - why are we breeding pigs just to slaughter them so we can harvest their organs?

GUSMANO: Right. I think the - you know, the positive response is, as one patient I interviewed suggested, you know, 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, you know, 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.

KELLY: Hmm. 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?

GUSMANO: 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.

KELLY: Hmm. 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?

GUSMANO: I think we're rapidly getting to a point where we probably have learned as much as we can from primate studies, from deceased donor modalities, now, of course, this compassionate-use intervention, where, if 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 xeno (ph) pig hearts don't function. These were both incredibly sick human beings who were very frail. It 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.

KELLY: 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?

GUSMANO: 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, you know, 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.

KELLY: Michael Gusmano of Lehigh University, where he is a professor of health policy - thank you so much for talking this through with us.

GUSMANO: Thank you. My pleasure.

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Jonaki Mehta is a producer for All Things Considered. Before ATC, she worked at Neon Hum Media where she produced a documentary series and talk show. Prior to that, Mehta was a producer at Member station KPCC and director/associate producer at Marketplace Morning Report, where she helped shape the morning's business news.
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Mary Louise Kelly is a co-host of All Things Considered, NPR's award-winning afternoon newsmagazine.