Geron To End Embryonic Stem Cell Research

Citing "capital scarcity" the Geron Corporation said it will abandon its research into using human embryonic stem cells to treat spinal cord injuries. Stem cell expert Leonard Zon discusses the announcement and what it means for the future of embryonic stem cell research.

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IRA FLATOW, HOST:

This is SCIENCE FRIDAY. I'm Ira Flatow.

For the rest of the hour, we'll look at the state of embryonic stem cell research. Earlier this week, the Geron Corporation announced it was abandoning its research into using embryonic stem cells to treat spinal cord injury. Geron was the first company to get the green light from the FDA to conduct clinical trials using embryonic stem cells. That was way back in 2009. And now, citing, quote, "capital scarcity and uncertain economic conditions," the company is looking to sell off that part of its business and focus on other work.

Joining me now to talk about the announcement, what it means for other research using embryonic stem cells is Leonard Zon. He is an investigator at the Howard Hughes Medical Institute and also director of the stem cell program at Children's Hospital Boston and professor of pediatrics at Harvard Med School. Welcome to SCIENCE FRIDAY. Welcome back.

DR. LEONARD ZON: Oh, thank you, Ira. It's a pleasure to be here.

FLATOW: Is this a real blow to stem cell, the embryonic stem cell research?

ZON: Well, we're certainly saddened by the decision to stop the trial in its midst, and it is, you know, upsetting that something would get this far along and have an issue. I think there's a lot going on in the field, and we still are very excited about the promise of stem cell research. But I think, as this illustrates, funding that research and looking for the ultimate therapies is going to take some time.

FLATOW: It's sort of a purely business decision then?

ZON: From my understanding, that's what happened here. So the company Geron had two paths: one was an oncology drug that seemed rather promising, was in phase two trial, and the other was to continue its stem cell research. It was clear that they had put a lot of money into stem cell research, and so they thought that would be a good path. But having to choose one or the other, they then chose the oncology drug path.

Now, we don't know everything about those decisions, and obviously there were some patients who were treated. So we don't know if all the decision was made as a business decision. But that's what I've been told informally.

FLATOW: So as you say, there were four patients who were under treatment, and they had hoped to treat 10 patients?

ZON: That's right. That's right. This is a very interesting trial. The idea was that there are embryonic stem cells which can make all the cells of your body, and these cells could be turned into supportive cells for neurons, for the brain cells and also for the spinal cord cells. And so the idea was once these cells were made, these supportive cells, they could be introduced into a patient who had a spinal cord injury, and they would start supporting the cells, and the repair of the neurons would be better if they were treated with the cell product. So, you know, we have four patients who are treated, and I guess they wanted to treat 10, and we'll have to follow those patients and see how they do.

FLATOW: 1-800-989-8255 is our number if you'd like to talk about this. You can also tweet us at scifri. These were early stage trial, right, just phase one?

ZON: That's right. So the idea was, really, a safety trial. If you were to take patients who are obviously devastated from having a spinal cord injury and then put in these supportive cells, we would want to make sure that they wouldn't cause any damage. And at least from the, you know, texts that we've had and other messages, it seems that there wasn't any major problem in terms of safety with the four patients who were treated.

A safety trial is only done for safety purposes. It's not to necessarily evaluate efficacy, how well it works. So I think we need to still see how the patients do, but again, it was to find out is the drug or these cells safe if you put them into a patient who's had a spinal cord injury.

FLATOW: By this company pulling out of actual testing of embryonic stem cell treatments, doesn't that cut drastically the number of companies left who are actually making those tests?

ZON: Yes, it's a very small list of companies. So actually, there's only one other company that's doing embryonic stem cell research, and that's a company called ACT. And they're trying to turn these embryonic stem cells into a cell that's in the eye. It's called a retinal pigment epithelial cell. But there are patients who have a genetic disease where those cells are defective, and they end up becoming blind. And the also more common disease, macular degeneration, also affects that cell population.

So that company hopes to use the embryonic stem cells to inject them into the eye and try to rescue the blindness or prevent the blindness that occurs in this particular genetic disease called Stargardt's disease. So short of that, there aren't other companies who are using embryonic stem cells, but there's a growing number of companies that are switching and trying to use reprogrammed skin cells.

When we talked last time a few years ago, we discussed how this new technology could take a skin cell and reprogram it to think it's an embryonic stem cell. And these cells, in many ways, have great abilities to be matched for the patient, let's say for their immune system. So there's a number of companies now who are trying to make those cells functional, and then trying to use them to do transplantation to fix a disease.

Those cells also end up being very interesting because you can make disease-specific cells. So you can take a disease and actually study it in a dish, a disease in a dish, and then try to find drugs that would be used to treat those diseases. And this is something that we're even seeing pharmaceutical companies get involved in, using stem cell technology.

FLATOW: What about the shortage now? As Geron backs out, don't they have a whole population of cells to use, and what's going to happen to that cell line or those cell lines that they have?

ZON: Absolutely. It's a very interesting discussion. We have to know that Geron has the largest number of cell lines that we know of for embryonic stem cells, and we would like to know what's going to happen to those stem cell lines. Obviously it's a business, and they probably will want, in their partnering opportunities, to sell it to another business. But it does create an issue for the stem cell field what will happen to those lines and how the - how will they be used in the future.

FLATOW: And would somebody take over continuing those lines, or do they just throw them out?

ZON: Well, that would be a very significant shame. I think that, you know, those lines are incredibly valuable, and we'd like to see them used for both biology as well as for medicine. And so, hopefully, they'll be placed in the care of a good company and they'll use them.

And, you know, I think what's interesting now when we look at this clinical trial is how it will - the results of the clinical trial actually get reported. You have four patients treated, and, you know, will they be followed? Will they be reported in the scientific literature? Those are also important things for the company to decide.

And if they're trying to partner that opportunity, how will their new partner or new - or when they sell the business, how will that company actually deal with that information? So both the lines as well as the dealing with the clinical trial that obviously these patients are already transplanted and will be followed, that's going to require some insight from the new company.

FLATOW: And if I recall, it was a huge regulatory hurdle for the company to overcome, all kinds of paperwork and documentation and expenses that way?

ZON: That's right. It's a - yeah. Absolutely. There was an amazing amount of paperwork that went into this. As you might expect when a totally new therapy comes about, the FDA is going to be involved in a very responsible way, ask for a number of experiments to be done, pre-clinical experiments that would allow them to ultimately do the trial. This took many, many years and many millions of dollars.

So, in a significant way, Geron has played an important role by forging this pathway of regulatory hurdles. So I think for future companies that come in, the FDA will know how to deal with this, to some degree, and I think that new therapies won't have to do as much work as has been done for Geron.

FLATOW: All right. Let's go to the phones, 1-800-989-8255. Let's go to Jerry(ph) in Cookeville, New Jersey. Hi, Jerry.

JERRY: Oh, that's Cookeville, Tennessee.

FLATOW: I'm sorry. Cookeville...

JERRY: That's OK.

FLATOW: That's close by, right?

JERRY: Yeah, but very interesting conversation with the - what the gentleman was just talking about with the human stem cells and all the promise that that's really showing. And as far as embryonic stem cells go, I really don't think that it's really done a whole lot, you know, considering all the different treatments. They use human stem cells. I mean, before long that will be like wanting to keep building wagons when the car is the wave of the future.

ZON: Well, I think it's interesting that the embryonic stem cell field really started in 1998 when the first human embryonic stem cells were derived. And you have a need to study those cells for many years before they can become interesting for biology, but also interesting as new therapies.

I often discuss - if you look at the history of organ transplant, for instance, bone marrow transplantation, a procedure that's done every day - even here at Children's Hospital we do hundreds every year - what happens is is that, in 1961, there was the discovery of the stem cell, and it didn't become a standard of therapy until about the late 1970s. So there's a large gap between the initial discoveries and then ultimately being successful.

And I do think that what this illustrates from Geron is it took a long time for the company to actually get this therapy into a patient, and that was very costly to deal with all the regulatory hurdles. And so that timeline is just not appetizing for venture capital companies as well as for large pharma. And so the timeline is long, and I think that makes people think, as the caller just said, that it's taking a long time before embryonic stem cells could be therapeutically useful.

FLATOW: Isn't that the weakness of the system, of allowing pharma to do this kind of research instead of having it, let's say, federally funded at NIH or someplace to develop this therapy? Because if they don't do it, if they drop it, it's not going to be developed.

ZON: Well, as you know, the entire field of organ transplantation was done completely academically initially. And then once it was clear that it was successful - and I would argue as soon as there's a success for embryonic stem cells or these new reprogrammed skin stem cells - then there will be an entire industry around being able to make it better.

I do think we were held up tremendously by NIH funding, which was not available in the 1990s through a presidential policy. But then, over time, that's been loosened up, and there is more money for embryonic stem cell research, and also for these skin reprogrammed cells that the NIH is investing in that particular area. So hopefully this will continue and that we'll see, over time, and, you know, over coming years, that this will be interesting therapeutically.

FLATOW: Mm-hmm. And where do we - let's talk about these stem cells, not the embryonic ones, but the other kinds that people can actually use their own cells and reprogram them. Is there any one disease to you, looking, surveying the field, that seems most promising at this point?

ZON: Well, I mean, at Children's Hospital, we're trying to use these to turn those cells into blood stem cells and being able to use those for patients who don't have a donor for marrow transplantation. I think that there's a lot of research going on in these skin cells - they're called iPS cells - and these skin cells, again, could be made from patients who have a particular disease. So we are making hundreds of lines of different genetic diseases.

We just made lines from a very rare blood disease - there's only 100 patients in the world who have that particular disease - so that we can study it and understand it. We make it from very common diseases, diabetes and Parkinson's disease also. So pretty much stem cell research could help the many diseases, but they're going to require significant investigation to study each of those diseases and their organs that are affected.

FLATOW: I'm Ira Flatow. This is SCIENCE FRIDAY from NPR. Talking with Leonard Zon, investigator at the Howard Hughes Medical Institute. Our number: 1-800-989-8255. Let's go to Richard in Penngrove, California. Hi.

RICHARD: Hi, Ira. Just love the show. And, Dr. Zon, I wondered if you were aware - I'm sure you are - of the story, which I only heard about on NPR in the last couple of days. And you'll forgive me. I've forgotten - I don't even think it was in the United States, and probably not because of the unfortunate backward policies that have caused some delay in our research. But the young - the very young, actually, baby - I guess it was in the first five days - was born and - either obtained or born with a virus which destroyed its - the young person's liver.

They were - they had done some clearance work before in research, before and had approval to go ahead, and this was the first case, apparently, that it was appropriate, injecting a liver stem cell into the young person - injecting or placing, I don't know how it was - with a coating from an algae, which allowed the membrane of the algae to provide a protective coating against the virus but permeable still so that it could actually take over and support liver functions until the young person's liver is healthy enough to restore him to normal health. And I believe he's several months old. Are you aware of this, sir?

ZON: Well, I'm, you know, I don't know that particular case. I heard a little bit about it, but not that much about it. It does illustrate how you can use a variety of cells and do transplantation and really affect things, affect organ function. And so we're just at the beginning of seeing how cell therapy can actually work, and so we see a number of studies to try to fix different heart disease and also, as you're illustrating, liver disease. I think that it's important that the people who are listening realize that some of these therapies are rational and have a scientific basis and should be done, and I believe what you're talking about was done in the correct - in a reputable institution.

I also just want to say that we are very concerned about stem cell tourism, so you do need to worry about some company, let's say, that is telling you they'll fix any type of disease through a particular cell population. And very frequently, we find that that group of companies is trying to make money rather than actually trying to help people. Having said that, I don't know this particular instance, so it sounds very fascinating.

FLATOW: But what you're saying is that as soon as someone, some company has a breakthrough in this and creates a real product, everybody else will want to join in on the bandwagon and starts investing more money and research in it.

ZON: I think that's true. I mean, we go back to - if you think about IVF, and at a certain point in time, there was a large debate about whether this was ethical as well as whether it should be done at all. And then as soon as there was a baby, I think that entire debate went away. I think if you look at organ transplants in the early - in the '60s and '70s, there were a number of patients who did extremely poorly from organ transplants and a number of the doctors were heavily criticized by trying to do these types of procedures as, you know, it would never work. But then as soon as there was a success, the entire field became much more invigorated, and we were able to see how it could become an industry as well as it could become a standard of therapy.

FLATOW: Dr. Zon, thank you for taking time to be with us today.

ZON: Well, thank you, Ira. It's a pleasure.

FLATOW: Happy holidays to you. Leonard Zon is a professor of pediatrics at Harvard Med School and also director of the Stem Cell Program at Children's Hospital in Boston.

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