Faster, Please! — The Podcast #32: The Accelerating CRISPR Revolution

Welcome to Faster, Please! — The Podcast. Several times a month, host Jim Pethokoukis will feature a lively conversation with a fascinating and provocative guest about how to make the world a better place by accelerating scientific discovery, technological innovation, and economic growth.

On Faster, Please! — The Podcast, I’ve interviewed guests on exciting new technologies like artificial intelligence, fusion energy, and reusable rockets. But today’s episode explores another Next Big Thing: biotechnology. To discuss recent advances in CRISPR gene editing and their applications for medicine, I’m sitting down with Kevin Davies.

Kevin is executive editor of The CRISPR Journal and author of the excellent 2020 book, Editing Humanity: The CRISPR Revolution and the New Era of Genome Editing.

In This Episode

• CRISPR advances over the past decade (1:13)
• What CRISPR therapies will come next? (8:46)
• Non-medical applications of gene editing (13:11)
• Bioweapons and the ethics of CRISPR (18:43)
• Longevity and genetic enhancements (25:48)

Below is an edited transcript of our conversation

CRISPR advances over the past decade

When people talk about AI, for instance, they might be talking about different versions or applications of AI—machine learning being one. So when we talk about CRISPR, are we just talking about one technique, the one they figured out back in 2012? Are there different ones? Are there improvements? So it’s really a different technique. So how has that progressed?

You’re right. CRISPR has become shorthand for genome editing. But the version of CRISPR that was recognized with the Nobel Prize three years ago in 2020 to Jennifer Doudna and Emmanuelle Charpentier was for one, we can call it the traditional form of CRISPR. And if I refer to it again, I’ll call it CRISPR-Cas9. Cas9 is the shorthand name for the enzyme that actually does the cutting of the DNA. But we are seeing extraordinary progress in developing new and even more precise and more nuanced forms of genome editing. They still kind of have a CRISPR backbone. They still utilize some of the same molecular components as the Nobel Prize–winning form of CRISPR. But in particular, I’m thinking of techniques called base editing and prime editing, both of which have commercial, publicly funded biotech companies pushing these technologies into the clinic. And I think over the next five to 10 years, increasingly what we refer to as “CRISPR genome editing” will be in the form of these sort of CRISPR 2.0 technologies, because they give us a much broader portfolio of DNA substitutions and changes and edits, and give the investigators and the clinicians much more precision and much more subtlety and hopefully even more safety and more guarantees of clinical efficiency.

Right. That’s what I was going to ask. One advantage is the precision, because you don’t want to do it wrong. You don’t want mutations. Do no harm first. A big advantage is maybe limiting some of the potential downsides.

In the ideal gene-editing scenario, you would have a patient with, say, a genetic disease that you can pinpoint to a single letter of the genetic code. And we want to fix that. We want to zero in on that one letter—A, C, T, or G is the four-letter alphabet of DNA, as I hope most of your listeners know—and we want to revert that back to whatever most normal, healthy people have in their genetic code at that specific position. CRISPR-Cas9, which won the Nobel Prize, is not the technology to do that sort of single base edit. It can do many other things, and the success in the clinic is unquestionable already in just a few years. But base editing and, in particular, prime editing are the two furthest developed technologies that allow investigators to pinpoint exactly where in the genome we want to make the edit. And then without completely cutting or slicing the double helix of DNA, we can lay up the section of DNA that we want to replace and go in and just perform chemistry on that one specific letter of DNA. Now, this hasn’t been proven in the clinic just yet. But the early signs are very, very promising that this is going to be the breakthrough genome-editing technology over the next 10 to 20 years.

Is CRISPR in the wild yet, or are we still in the lab?

No, we’re in the clinic. We are in human patients. There are at least 200 patients who have already been in or are currently enrolled in clinical trials. And so far, the early results—there are a few caveats and exceptions—but so far the overwhelming mood of the field is one of bullish enthusiasm. I don’t want to complete this interview without singling out this one particular story, which is the clinical trial that has been sponsored by CRISPR Therapeutics and Vertex Pharmaceuticals for sickle cell disease. These are primarily African-American patients in this country because the sickle cell mutation arose in Africa some 7,000 years ago.

We’re talking about a pretty big share of the African-American population.

This is about 100,000 patients just in America, in the US alone. And it’s been a neglected disease for all kinds of reasons, probably beyond the scope of our discussion. But the early results in the first few dozen patients who have been enrolled in this clinical trial called the exa-cel clinical trial, they’ve all been cured. Pretty much all cured, meaning no more blood transfusions, no more pain crises, no more emergency hospitalizations. It is a pretty miraculous story. This therapy is now in the hands of the FDA and is speeding towards—barring some unforeseen complication or the FDA setting the bar so high that they need the investigators to go back and do some further checks—this should be approved before the end of this year.

There’s a catch, though. This will be a therapy that, in principle, will become—once approved by the FDA and the EMA in Europe, of course—will become available to any sickle cell patient. The catch will, of course, be the cost or the price that the companies set, because they’re going to look for a return on their investment. It’s a fascinating discussion and there’s no easy answer. The companies need to reward their shareholders, their investors, their employees, their staff, and of course build a war chest to invest in the next wave, the next generation of CRISPR therapies. But the result of that means that probably we’re going to be looking at a price tag of, I mean, I’m seeing figures like $1.9 million per patient. So how do you balance that? Is a lifetime cure for sickle cell disease worth $2, maybe $3 million? Will this patient population be able to afford that? In many cases, the answer to that will be simply, no. Do you have to remortgage your house and go bankrupt because you had a genetic quirk at birth? I don’t know quite how we get around this.

Different countries will have different answers with different health systems. Do you have a sense of what that debate is going to be like in Washington, DC?

It’s already happening in other contexts. Other gene therapies have been approved over the last few years, and they come with eye-watering price tags. The highest therapy price that I’ve seen now is $3.5 million. Yes, there are discounts and waiver programs and all this sort of stuff. But it’s still a little obscene. Now, when those companies come to negotiate, say, with the UK National Health Service, they’ll probably come to an agreement that is much lower, because the Brits are not going to say that they’re going to be able to afford that for their significant sickle cell population.

Is it your best guess that this will be a treatment the government pays for?

What’s interesting and what may potentially shift the calculus here is that this particular therapy is the disease affects primarily African-Americans in the United States. That may change the political calculus, and it may indeed change the corporate calculus in the boardrooms of Vertex and CRISPR Therapeutics, who may not want the backlash that they’re going to get when they say, “Oh, by the way, guys, it’s $2 million or you’re out of luck.”

What CRISPR therapies will come next?

And after this CRISPR treatment for sickle cell disease is available, what therapies will come next?

Probably a bunch of diseases that most people, unless they are unfortunate enough to have it in their family, won’t have heard of. There are companies that are studying using CRISPR to potentially correct the mutations that cause genetic forms of blindness, genetic forms of liver disease. It turns out the liver is an organ that is very amenable to taking up medicines that we can inject in the blood. The other big clinical success story has come from another company in the Boston area called Intellia Therapeutics. Also publicly traded. They’ve developed CRISPR therapies that you can inject literally into the body, rather than taking cells out and doing it in the lab and then putting those cells back in, as in the case of sickle cell.

I’m not sure that was actually even clear: that you can do it more than one way.

Yes.

And obviously it sounds like it would be better if they could just inject you.

Exactly. That’s why people are really excited about this, because this now opens up the doors for treating a host of diseases. And I think over the next few years we will see a growing number of diseases, and it won’t just be these rare sort of genetic diseases with often unpronounceable names. It may be things like heart disease. There’s another company—they’re all in Boston, it seems—Verve Therapeutics, which is taking one of these more recent gene-editing technologies that we talked about a minute ago, base editing, and saying that there’s a gene that they’re going to target that has been clearly linked with cholesterol levels. And if we can squash production of this gene, we can tap down cholesterol levels. That will be useful, in the first instance, for patients with genetic forms of high cholesterol. Fair enough. But if it works in them, then the plan is to roll this out for potentially thousands if not millions of adults in this country who maybe don’t feel that they have a clearly defined genetic form of high cholesterol, but this method may still be an alternative that they will consider versus taking Atorvastatin for the rest of your life, for example.

Where are the CRISPR cancer treatments?

They’re also making progress, too. Those are in clinical trials. A little more complicated. Of course, cancer is a whole slew of different diseases, so it’s a little hard to say, “Yeah, we’re making progress here, less so there.” But I think one of the most heartwarming stories—this is an n of one, so it’s an anecdotal story—but there was a teenager in the UK treated at one of the premier London medical schools who had a base editing form of CAR T therapy. A lot of people have heard of CAR T therapy for various cancers. And she is now in remission. So again, early days, but we’re seeing very positive signs in these early clinical tests.

It sounds like we went from a period where it was all in the lab and that we might be in a period over the next five years where it sounds like a wave of potential treatments.

I think so, yeah.

And for as much as we’ve seen articles about “The Age of AI,” it really sounds like this could be the age of biotechnology and the age of CRISPR…

I think CRISPR, as with most new technologies, you get these sort of hype cycles, right? Two and a half years ago, CRISPR, all the stocks were at peak valuations. And I went on a podcast to say, why are the CRISPR stocks so high? I wasn’t really sure, but I was enjoying it at the time. And then, of course, we entered the pandemic. And the biotech sector, perversely, ironically, has really been hit hard by the economy and certainly by the market valuations. So all of the CRISPR gene-editing companies—and there are probably at least eight or 10 now that are publicly traded and many more poised to join them—their valuations are a fraction of what they were a couple of years ago. But I suspect as these first FDA approvals and more scientific peer review papers, of course, but more news of the clinical success to back up and extend what has already been clearly proven as a breakthrough technology in the lab with the Nobel Prize—doesn’t get much better than that, does it?—then I think we’re going to start to see that biotech sector soar once again.

Non-medical applications of gene editing

There are also non-medical applications. Can you just give me a little state of play on how that’s looking?

I think one of the—when CRISPR…

And agriculture.

Feeding the planet, you could say.

That’s certainly a big application.

It’s a human health application—arguably the biggest application.

I think one of the fun ones is the work of George Church at Harvard Medical School, who’s been on 60 Minutes and Stephen Colbert and many other primetime shows, talking about his work using CRISPR to potentially resurrect the woolly mammoth, which sort of sounds like, “That’s Jurassic Park on steroids. That’s crazy.” But his view is that, no, if we had herds—if that’s the technical term—of woolly mammoths—roaming Siberia and the frozen tundra, they’ll keep the ground, the surface packed down and stop the gigatons of methane from leaching out into the atmosphere. We have just seen a week, I’ve been reading on social media, of the hottest temperatures in the world since records began. And that’s nothing compared to what we’re potentially going to see if all these greenhouse gases that are just under the surface in places like Siberia further leach into the atmosphere. So that’s the sort of environmental cause that Church is on. I think many people think this is a rather foolish notion, but he’s launched a company to get this off the ground called Colossal Biosciences, and they’re raising a lot of money, it appears. I’m curious to see how it goes. I wish him well.

Also, speaking of climate change, making crops more resilient to the heat. That’s another I’ve heard…

One of the journals I’m involved in, called GEN Biotechnology, just published a paper in which investigators in Korea have used CRISPR to modify a particular gene in the tomato genome to make it a higher source of vitamin D. And that may not seem to be the most urgent need, but the point is, we can now engineer the DNA of all kinds of plants and crops, many of which are under threat, whether it’s from drought or other types of climate change or pests, bacteria, parasites, viruses, fungi, you name it. And in my book Editing Humanity, which came out a couple of years ago, there was a whole chapter listing a whole variety of threats to our favorite glass of orange juice in the morning. That’s not going to exist. If we want that all-natural Florida orange juice, we’re not going to have that option. We’ve either got to embrace what technology will allow us to do to make these orange crops more resistant to the existential threat that they’re facing, or we’re going to have to go drink something else.

I started out talking about AI and machine learning. Does that play a role in CRISPR, either helping the precision of the technology or in some way refining the technology?

Yeah, hopefully you’ll invite me back in a year and I’ll be able to give you a more concrete answer. I think the short answer is, yes. Certainly, there are a lot of computational aspects to CRISPR in terms of designing the particular stretches of nucleic acid that you’re going to use to target a specific gene. And AI can help you in that quest to make those ever more precise. When you do the targeting in a CRISPR experiment, the one thing you don’t want to have happen is for the little stretch of DNA that you’ve synthesized to go after the gene in question, you don’t want that to accidentally latch onto or identify another stretch of DNA that just by statistical chance has the same stretch of 20 As, Cs, Ts, and Gs. AI can help give us more confidence that we’re only honing in on the specific gene that we want to edit, and we’re not potentially going to see some unforeseen, off-target editing event.

Do you think when we look back at this technology in 10 years, not only will we see a wider portfolio of potential treatments, but we’ll look at the actual technique and think, “Boy, back in 2012, it was a butchery compared to what we’re doing; we were using meat cleavers, and now we’re using lasers”?

I think, yeah. That’s a slightly harsh analogy. With this original form of CRISPR, published in 2012, Nobel Prize in 2020, one of the potential caveats or downsides of the technology is that it involves a complete snip of the double helix, the two strands of DNA, in order to make the edit. Base editing and prime editing don’t involve that double-stranded severance. It’s just a nick of one strand or the other. So it’s a much more genetically friendly form of gene editing, as well as other aspects of the chemistry. We look forward to seeing how base and prime editing perform in the clinic. Maybe they’ll run into some unforeseen hurdles and people will say, “You know what? There was nothing wrong with CRISPR. Let’s keep using the originally developed system.” But I’m pretty bullish on what base and prime editing can do based on all of the early results have been published in the last few years on mice and monkeys. And now we’re on the brink of going into the clinic.

Bioweapons and the ethics of CRISPR

This podcast is usually very optimistic. So we’re going to leave all the negative stuff for this part of the podcast. We’re going to rush through all the downsides very quickly.

First question: Especially after the pandemic, a lot more conversation about bioweapons. Is this an issue that’s discussed in this community, about using this technology to create a particularly lethal or virulent or targeted biological weapon?

Not much. If a rogue actor or nation wanted to develop some sort of incredibly virulent bioweapon, there’s a whole wealth of genetic techniques, and they could probably do it without involving CRISPR. CRISPR is, in a way, sort of the corollary of another field called synthetic biology or synthetic genomics that you may have talked about on your show. We’ve got now the facility, not just to edit DNA, but to synthesize custom bits of DNA with so much ease and affordability compared to five or 10 years ago. And we’ve just seen a global pandemic. When I get that question, I’ve had it before, I say, “Yeah, did we just not live through a global pandemic? Do we really need to be engineering organisms?” Whether you buy the lab leak hypothesis or the bioengineering hypothesis, or it was just a natural transfer from some other organism, nature can do a pretty good job of hurting human beings. I don’t know that we need to really worry too much about bioweapons at this point.

In 2018, there was a big controversy over a Chinese researcher who created some genome-edited babies. Yeah. Is there more to know about that story? Has that become a hotter topic of discussion as CRISPR has advanced?

The Chinese scientist, He Jiankui, who performed those pretty abominable experiments was jailed for the better part of three years. He got early release in China and slowly but surely he’s being rehabilitated. He’s literally now moved his operation from Shenzhen to Beijing. He’s got his own lab again, and he’s doing genome editing experiments again. I saw again on social media recently, he’s got a petition of muscular dystrophy families petitioning Jack Ma, the well-known Chinese billionaire, to fund his operation to devise a new gene editing therapy for patients with Duchenne muscular dystrophy and other forms of muscular dystrophy. I wouldn’t want He Jiankui let within a thousand miles of my kids, because I just wouldn’t trust him. And he’s now more recently put out a manifesto stating he thinks we should start editing embryos again. So I don’t know quite what is going on.

It seems the Chinese threw the book at him. Three years is not a trivial prison sentence. He was fined about half a million dollars. But somebody in the government there seems to be okay with him back at the bench, back in the lab, and dabbling in CRISPR. And I don’t know that he’s been asked, does he have any regrets over the editing of Lulu and Nana. There was a third child born a few months later as well. All he will say is, “We moved too fast.” That is the only caveat that he has allowed himself to express publicly.

We know nothing more about the children. They’re close to five years old now. There’s one particular gene that was being edited was pretty messed up. But we know it’s not an essential gene in our bodies, because there are many people walking around who don’t have a functional copy of this CCR5 receptor gene, and they’re HIV resistant. That was the premise for He Jiankui’s experiment. But he has said, “No, they are off limits. The authorities are not going to reveal their identities. We are monitoring them, and we will take care of them if anything goes wrong.” But I think a lot of people in the West would really like to help, to study them, to offer any medical assistance. Obviously, we have to respect their privacy. The twin girls and the third child who was born a bit later, maybe they’re being protected for their own good. How would you like it if you grew up through childhood and into your teenage years, to walk around knowing that you were this human experiment? That may be a very difficult thing to live with. So more to come on that.

There’s no legitimate discussion about changing that in the West or anywhere else?

Obviously, in the wake of what He Jiankui did, there were numerous blue ribbon panels, including one just organized by the National Academy of Sciences, just a stone’s throw from where we’re talking today. And I thought that report was very good. It did two things. This was published a couple of years ago. Two important things came out of it. One is this all-star group of geneticists and other scientists said, “We don’t think that human embryo editing should be banned completely. There may be scenarios down the road where we actually would want to reserve this technology because nothing else would help bring about a particular medical outcome that we would like.” And the one medical scenario that they laid out would be, what if two people with a deadly recessive disease like sickle cell disease, or perhaps a form of cystic fibrosis, wanted to have a healthy biological child?

There are clinics around the country and around the world now doing something called pre-implantation genetic diagnosis. If you have a family history of a genetic disease, you can encourage the couple to do IVF. We form an embryo or bunch of embryos in the test tube or on the Petri dish. And then we can do a little biopsy of each embryo, take a quick sneak peek at the DNA, look to see if it’s got the bad gene or perhaps the healthy gene, and then sort of tag the embryos and only implant the embryos that we think are healthy. This is happening around the country as we speak for hundreds, if not thousands, of different genetic diseases. But it won’t work if mom and dad have a recessive, meaning two copies of a bad gene, because there’s no healthy gene that you can select in any of those embryos. It would be very rare, but in those scenarios, maybe embryo editing is a way we would want to go. But I don’t see a big clamor for this right now. And the early results have been published using CRISPR on embryos in the wake of He Jiankui did have said, “It’s a messy technique. It is not safe to use. We don’t fully understand how DNA editing and DNA repair works in the human embryo, so we really need to do a whole lot more basic science, as we did in the original incarnation of CRISPR, before we even dare to revisit editing human embryos.”

Longevity and genetic enhancements

Another area is using these treatments not to fix things, but to enhance people, whether it’s for intelligence or some other trait. A lot of money pouring into longevity treatments from Silicon Valley. Do we know more about the potential of CRISPR for either extending lifespans or selecting for certain desirable traits in people?

This sort of scenario is never going to go away. When it comes up, if I hear someone say, “Could we use CRISPR or any gene editing technology to boost intelligence or mathematical ability or music musical ability, or anything that we might want…”

Or speed in the hundred meters.

“…or speed in the hundred meters, to enhance our perfect newborn?” I would say, what gene are you going to enhance? Intelligence—are you kidding me? Half of the 10,000 genes are expressed in the human brain. You want to start meddling with those? You wouldn’t have a prayer of having a positive outcome. I think we can pretty much rule that out. Longevity is interesting because, of course, in the last 18 months there’s a company in Silicon Valley called Altos, funded by Yuri Milner, employing now two dozen of the top aging researchers who’ve been lured away from academia into this transnational company to find hopefully cures or insights into how to postpone aging. That’s going to be a long, multi-decade quest to go from that to potentially, “Oh, let’s edit a little embryo, our newborn son or daughter so they have the gift of 120 years on this decaying, overheating planet…” Yes, there’s a lot to wade through on that.

And you have another book coming out. Can you give us a preview of that?

I’m writing a book called Curved Air, which is about the story of sickle cell disease. It was first described in a paper from physicians in Chicago in 1910 who were studying the curious anemia of a dental student who walked into their hospital one day. That gentleman, Walter Noel, is now buried back in his homeland, the island of Grenada. But in the 1940s, it was described and characterized as the first molecular disease. We know more about sickle cell disease than almost any other genetic disease. And yet, as we touched on earlier, patients with this who have not had the wealth, the money, the influence, they’ve been discriminated against in many walks of life, including the medical arena.

We’re still seeing terribly, tragically, videos and stories and reports of sickle cell patients who are being turned away from hospital rooms, emergency rooms, because the medical establishment just looks at a person of color in absolute agony with one of these pain crises and just assumed, “Oh, they want another opioid hit. Sickle cell? What is that?” There’s a lot of fascinating science. There’s all this hope in the gene editing and now in the clinic. And there’s all this socioeconomic and other history. So I’m going to try to weave all this together in a format that hopefully everyone will enjoy reading.

Hopefully a book with a happy ending. Not every book about a disease has a wonderful…

I think a positive note to end on is the first American patient treated in this CRISPR clinical trial for sickle cell disease four years ago, Victoria Gray, has become something of a poster child now. She’s been featured on National Public Radio on a whole series of interviews and just took her first overseas flight earlier this year to London to speak at a CRISPR gene editing conference. She gave a lovely 15-minute personal talk, shaking with nerves, about her personal voyage, her faith in God, and what’s brought her here now, pain-free, traveling the world, and got a standing ovation. You don’t see many standing ovations at medical conferences or genetics conferences. And if ever anybody deserved it, somebody like Victoria Gray did. Early days, but a very positive journey that we’re on.