Tag Archives: gene editing

Top Ten Stories in Genetics in 2017

Mark it in your calendar: 2017 was the year when gene therapy (broadly defined) became something more than hypothetical.  Hard to talk about 2017 as a great year, but that’s the storyline in genetics.  Here’s the countdown:

  1. Ohio Bans Abortions for a Fetus Affected with Down Syndrome

In December 2017, Ohio became the 3rd state to criminalize abortion to avoid the birth of a child with a genetic condition. The first law was passed in North Dakota in 2013 and remains on the books, and a similar measure in Indiana that focuses specifically on Down syndrome was enjoined by court order after an ACLU challenge.

Ohio’s law makes it a felony to perform an abortion if the patient’s motivation is to avoid the birth of a child with Down syndrome. These laws appear unlikely to be enforced: unconstitutional under Roe v Wade, they should not survive a court challenge, and if they did, they would be incredibly difficult to enforce. Still, there are several reasons why it is worth paying attention to what must now officially be called a trend.

First, these laws didn’t pop up organically, and they indicate that therapeutic abortion is on the radar of anti-abortion groups. Expect more of the same, and battles on related fronts, including insurance coverage for prenatal testing.

Second, even if the law is never enforced, it could affect practice. A woman’s motivation is hard to prove, but the motivation of a genetic counselor or a physician discussing termination after a diagnosis of Down syndrome is crystal clear, and could put them at risk. Even a distant and unlikely threat of a felony prosecution is a great disincentive to any clinician. Discouraging counseling may pr may not prevent abortion but it absolutely deprives couples of the good, unbiased information that Down syndrome advocates have been working on for years. And as usual, it increases disparities in care for individuals with fewer resources or less education.

Third, polling suggests that a slim majority of the country believes abortion should be available for pregnant women when the fetus faces cognitive impairment, but it’s emotionally tricky territory and norms may shift to make therapeutic abortion more stigmatized. There’s a reason why the second and third iterations of the law specified Down syndrome: this is a public relations campaign and Down syndrome kids present a sweet and photogenic face. “Every Ohioan deserves a right to life, no matter how many chromosomes they have,” said the head of the Ohio Right to Life, neatly eliminating the difference between a fetus and a child.

Fourth, expect a whole lot more of this if we lose Roe v Wade.

  1. STAT names the Swiss Army Knife the top CRISPR metaphorScreen Shot 2017-12-29 at 7.26.31 PM.png

Bacteria have been using CRISPR for aeons, but humans have only had it in their gene editing toolkit for five years. In that short span, technical advancements have occurred so quickly that 2012 CRISPR is starting to feel a bit old school. Some of these innovations improve the original CRISPR search-and-delete functionality – reducing off target effects, for example, or improving the odds of replacing deleted DNA segments with a scripted sequence delivered via a template. Other advancements add new types of functionality. In 2017, researchers introduced a modified CRISPR system uses the same search function but doesn’t cut; instead, it alters gene expression by changing the elaborate system of packaging that turns gene on or off. In another iteration of CRISPR search-and-don’t-cut functionality, scientists from Harvard and the Broad Institute have pioneered a technique called base editing, which locates a specific spot in the DNA sequence and replaces a single base through a series of chemical reactions without the riskier business of inducing a double-stranded break. In October, researchers from China announced that they had tested base editing in human embryos, and were able to correct a mutation that causes the blood disease beta thalassemia 23% of the time.

The proliferation of CRISPR varietals led writers at STAT to give top honors to “the Swiss army knife” in a ranking of CRISPR metaphors (runner up: “organic photoshop”).

 

  1. Harvard’s George Church opens up the George Church Institute in ChinaScreen Shot 2017-12-10 at 4.37.03 PM.png

Synthetic DNA made significant steps forward this year, starting with an announcement in January that researchers at the Scripps Institute in La Jolla have produced a modified a strain of E coli whose DNA has six rather than the usual four base pairs. The following October, in a story that my be the epitome of 2017, Harvard professor George Church traveled to China to announce the opening of the eponymous George Church Institute of Regenesis. This collaboration with Chinese giant BGI has plans to develop clinical applications of synthetic biology. The investment of substantial resources in artificial life forms and bio-manufacturing is one indication of where we are headed; sadly, the decision by one of America’s great science talents to launch an ambitious project halfway across the world may also prove to be a sign of things to come.

 

  1. Popular Culture Discovers CRISPR

This was the year I read my first sci-fi novel about a world where children (and pets) are routinely gene-edited. Although it was a dystopian vision, I have to admit I was intrigued by the tiger-ized house cat…

CRISPR has definitely captured the imagination of a good part of the universe, and my sense is that the jury is out on whether our new powers of gene editing are going to be viewed as cool or creepy. Meanwhile, here’s some unexpected places where CRISPR popped up in 2017.

On Jeopardy!

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In Ashton Kutcher’s twitter feed:

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Graffitied on the mean streets of San Francisco:

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This is a sleeper pick at number 7, but I believe it’s important to understand that people are paying attention, because (like the rest of us) they don’t yet know what to think. The early uses of CRISPR will have a great impact on public opinion, and very likely on support for research, development and commercialization of gene editing down the road. It’s something to think about.

 

  1. The FDA Changes Direction on DTC Genetic Testing

The FDA executed a remarkable about-face on direct-to-consumer genetic testing in 2017, beginning in April when the agency approved a new iteration of their SNP scan for liability to disease, 3 ½ years after they shut down sales of the alpha version, claiming it posed a risk to the health of those who bought it. In addition to signing off on testing for 10 complex conditions where the genetic contribution is important but not definitive, the FDA announcement established some ground rules that could be applied to other tests and other companies. First, the decision identified 23andMe as what they called a ‘trusted provider’ and indicated that having been so designated, they would not have to jump through regulatory hoops for every new test, and would be exempt from premarket review. Second, the agency created a category called “genetic health risk (GHR)” tests, as distinct from genetic tests that were diagnostic, which were explicitly excluded from exemption.

Presumably, the agency’s goal was twofold: to remove impediments to the growth of DTC, while carving out some rules for what belonged in that realm, as distinct from what belonged in a clinical setting. In November, the FDA made this explicit, announcing its intention to establish a new regulatory structure for GHR tests which would formalize the ‘trusted provider’ approach through a one-day FDA review, allowing them to introduce non-diagnostic tests and carrier screens without further premarket scrutiny.

This change in governance is likely a response to what is happening in Washington, where anti-regulatory sentiment is rife, and may also be due to changes in the marketplace, with major players like Illumina and Google making sizeable bets on DTC genetic testing ventures. There is little question that the FDA moves have had a big impact, and the fledgling DTC industry appears to have spread its wings and taken off. Strong Christmas sales for both Ancestry.com and 23andMe indicate that consumers are willing to give genetic testing a try; sustained success may be contingent on how that experience goes for the recipients.

 

  1. First RNAi Drugs Show Promise in Human Trials

Many of the early targets of gene therapy are diseases caused by a single missing or defective protein, and the goal in these cases is to introduce a gene that will produce what the body is lacking. Despite the fact that we have not been very successful to date, it is a simple model; often replacing a small fraction of normal production is enough to treat or effectively cure the disease. In some diseases, however, the problem is not the absence of a normal protein but the presence of an abnormal one which disrupts function or damages healthy tissue. In these cases, you can’t simply (‘simply’) replace what you don’t have but must find a way to silence the gene product that is causing all the trouble.

One way to do this is to intercept the RNA messages before they are made into protein via RNA interference – designer RNA’s that find and bind to specific transcripts to prevent translation. Like many other forms of what might broadly be called gene therapy (I’m not into fights about semantics so don’t @ me), RNAi has not fulfilled it’s conceptual promise to date, but that seems to be on the verge of changing. In October Ionis Pharmaceuticals launched the first human trials of a RNAi drug for Huntington’s disease, and in November a Cambridge-based company called Alnylam announced that its RNAi drug for hereditary ATTR amyloidosis was showing success in phase 3 trials and might be up for FDA review in 2018.

 

  1. In Vivo Gene Editing Mitigates Deafness (in Mice)

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In another late entry into the Top Stories of 2017, researchers from the lab of David Liu published a December article in nature describing the use of in vivo gene editing to facilitate hearing in mice bred to exhibit a form of genetic deafness found in humans. Mice injected with CRISPR-Cas9 complexes showed more hair cells and improved response to auditory testing. While it is always good practice to remind ourselves that not everything that works in rodents works in people but… in vivo gene editing is a remarkable technical achievement with incredible potential. Brought to you, by the way, by a co-founder of Editas Medicine, so this maybe this blog post can double as a stock tip. 2017, ladies and gentlemen.

 

  1. A Gene Therapy Ready for Prime Time at Last!

We’ve been talking about gene therapy for so long it seems like old hat, except that this particular old hat has never been thrown into the ring… until now. On December 19th, the FDA approved Luxturna, a gene therapy for blindness. First of its kind, Luxturna introduces a gene into retinal cells by a viral vector and, in cells where uptake of the wildtype variant increases the production of normal protein.

Eyeballs are a uniquely accessible body part, making them low-hanging fruit for gene therapy, but low-hanging fruit is the place to start, and the take-home point here is that the new and improved gene editing technology and gene delivery systems are for real, as is (finally) gene therapy. Coming soon: gene therapies for blood-based diseases such as hemophilia and sickle cell. Still to be determined: how much all of this will cost.

 

  1. Immunotherapy Delivers a One-two Punch

The cancer field has been buzzing about Car-T therapy for years, hopeful that this new class of therapies designed to harness the body’s own immune system would not only expand the range of cancers we could fight, but do so in a targeted fashion that would reduce the toxicity associated with current chemotherapies. Immunotherapy has been through several rounds of hype-and-hate before getting out of the clinical trial phase, as stories about patients rescued from the deathbed have sent up smiley face trial balloons and deaths from unanticipated side effects have popped them.

After all the anticipation, approval of the first two Car-T drugs came only weeks apart, with Kymriah, a drug for pediatric leukemia, approved in August and Yescarta, for some forms of B-call lymphoma, following close behind. All the usual caveats apply – real-world safety and efficacy still to be worked out over time, and price price price price price plus access, but without setting that aside, I want to take a moment to congratulate everyone who worked to create and validate this new and important class of cancer therapies.

 

  1. The Boy who Got New Skin Is Everything You Ever Hoped For in a Stem Cell Success Story

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I was six paragraphs into Ed Yong’s story about a boy with epidermolysis bullosa when I realized it was going to be my top story in genetics for 2017. How many things are there to love about this story? First of all, it’s about a cure for EB, a disease that disrupts the normal structure of the skin, making it fragile, so that it is prone to rupture and blister. In bad cases, people are plagued with open sores that will not heal. It’s a biblical plague of a disease, and this kid was in terrible shape – shape – seven years old, and headed to hospice care.

And they fixed him.  This is also a stem cell success story, joining the list of finally-finally-at last therapeutic success stories in 2017. Doctors removed a small patch of precious intact skin from seven-year-old Hassan and sent it to researchers in Italy, who isolated and corrected skin stem cells, and then used them to grown sheets of skin in which to sheath the dying child. They replaced an astounding 80% of his old skin and – here’s the part from paragraph six – less than a year later he is back in school, playing sports and living the life of a normal child.

I promised myself never to talk about these high tech miracles without discussing cost and access, so here I raise relevant questions: what’s this going to cost, and who will be able to get it?   Honestly, I have no idea.   And for the record, this technique won’t work for all variants of the disease.  But there is a lot to celebrate.

It seems strange to talk about 2017 as a series of victories for humanity, but the year in genetics was full of hope and promise, and nowhere was that contrast more on display than here, in the a story of a global community coming together to save a life. A Syrian child, treated by German doctors together with Italian researchers who were mentored by an American pioneer…  It was the epitome of 2017 in genetics, though sadly not the epitome of 2017 in any other sphere.

 

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