CRISPR Tech Heralds Hype, Hope, and Hurdles for Gene-Based Therapeutics

December 12, 2016

or: How to Cure Cancer and AIDS with This One Weird Trick

By Joe Stanganelli 

December 12, 2016 | CRISPR, which has been lauded as a “jawdropping breakthrough” and “the biggest biotech discovery of the century” (the fact that more than 80% of the 21st century still lies ahead of us notwithstanding), has been an especially hot topic of late. The age of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) has heralded in new lines of business based on cutting-edge, gene-editing technologies.

"There is not a program or platform in this building that is not using CRISPR in some way," said Paul Goldsmith, a media relations specialist at the Broad Institute, in an interview with Bio-IT World.

Recent highlights include:

  • Discoveries by transgenic lab rodent and CRISPR-based genome-editing company Applied StemCell, in a study titled CRISPR Efficiency in Blood Derived Immune Cells using Cas9 Plasmids and RNA binding protein (RNP), that the activity of synthetic "Guide RNAs" (a.k.a. gRNA) that serve as Cas9-based sequences in CRISPR editing varies across different cell lines. The discovery suggests that the efficiency of CRISPR-based gene editing differs in different tissue—even varying among cells from the same lineage. (Applied StemCell shared hard copies of the study at the Discovery on Target conference.)
  • Thermo Fisher Scientific is in the process of developing and releasing CRISPR-based tools that can inhibit or activate mRNA without resorting to permanent gene edits that are typical to Cas9-based gene editing

CRISPR: Cutting to the Chase

CRISPR-based gene-editing is akin to taking microscopic scissors—typically Cas9 (CRISPR-associated protein 9)—to a specific spot in the genome guided by an RNA molecule, snipping, and then splicing the genome back together, like a film editor might do with a movie reel in the pre-digital era. Accordingly, CRISPR offers an extremely high level of precision in gene editing, requiring less customization than alternative gene-editing vehicles, such as zinc-finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs). It is unsurprising, therefore, that CRISPR/Cas9-based genetic editing has been hailed a major improvement.

November 2016 marked the third anniversary of initial announcements of CRISPR's potential as a "breakthrough." Since then, the CRISPR industry has been one of warp-speed evolution and constant upheaval.

"CRISPR technology is changing so rapidly on a month-to-month basis that our tools are becoming outdated," lamented Vinit Mahajan, Assistant Professor of Ophthalmology and Visual Sciences at the University of Iowa College of Medicine, at Discovery on Target 2016* in Boston earlier this year as he presented a CRISPR-focused session titled CRISPR in Mouse Models of Eye Disease.

Both industry conference presentations and news announcements alike over the past few months have been rife with new scientific developments in the CRISPR realm.

“Advances in genome modulation have the potential to change the way we create energy, produce food, optimize industrial processing, and detect, prevent, and cure diseases—improving the human condition and the world around us,” reads a Thermo Fisher Scientific report titled Genome Modulation and Engineering Services—Collaborating as Partners to Accelerate Your Discovery. “Through innovative design and engineering, this unique science enables researches to study, alter, create, and re-create highly complex pathways, DNA sequences, genes, and natural biological systems in order to understand and answer some of life's most challenging questions.”

CRISPR Breeds Caution

Despite the hoopla over CRISPR this year, however, not everyone in the genomics industry is sold on the immediacy of the hype.

“This is a great technology. I think CRISPR is really a breakthrough technology [and] has a lot of potential, but [with] this version of CRISPR—I call it ‘Version 1.0’—we should not expect therapeutic application for [another] 10 years,” opined Ruhong Jiang, CEO of Applied StemCell, in an interview with Bio-IT World. “You cannot push science; you need time to accumulate.”

CRISPR’s three-year history is not really all that long in the realm of the life sciences, a field where experiments and studies that are more than 20 years old are still referenced, cited, and built upon. And Jiang cited a laundry list of obstacles still facing CRISPR, related technologies, and the companies creating, using, and licensing them. Not least of these—as with all therapeutic developments—is a regulatory one.

“This is a regulatory business,” said Jiang. “Number one: you look at the number of papers published [in the area]. Number two: [you] look at the clinical trials.”

The CRISPR Rat Race (or: Of Mice and Men)

Despite conceding that “the FDA really understands the genetic technology [and] how gene-editing technology works,” Jiang maintained that “It takes 20 years for a given technology [to be approved for] clinical application.”

“Drugs are expensive to bring into trial,” points out geneticist and former Broad Institute affiliate Jim Kozubek in a recent Boston Globe op-ed, “[and] the FDA has identified CRISPR/Cas9 as a drug, not a device[.]”

Indeed, while CRISPR played a feature role throughout much of this year's Discovery on Target conference, most presentations, whitepapers, and other discussions highlight just how nascent the technology is: most materials featured CRISPR- and Cas9-based technology's application to lab mice and lab rats (developments in CRISPR-modified produce, such as corn and cabbage, notwithstanding).

One of the latest and greatest new developments in CRISPR/Cas9 technology application was announced on November 30 by biomedical researchers at the University of Pennsylvania. “For the first time”, they said, they have corrected clotting problems in both newborn and adult mice using CRISPR/Cas9. Their eventual aim is to one day cure the “majority of patients” with hemophilia B via CRISPR/Cas9-based gene targeting.

“Basically, we cured the mice,” said Lili Wang, a research associate professor at U-Penn and the study's first author. “This study provides convincing evidence for efficacy in a hemophilia B mouse model following in vivo genome editing by CRISPR/Cas9.”

To be certain, even Jiang’s Applied StemCell’s marketing collateral is focused on the effects of the company’s gene-editing products on gene knock-in, knockout, and conditional knockout for mouse models and rat models.

Exceptionally heightened interest in the technology is speeding the transition to research in humans. Late last month, CRISPR/Cas9 gene-editing technology was tested on a human being for the first time. Scientists at West China Hospital in Chengdu, China, injected an apparently-terminal lung cancer patient (who is very much human) with CRISPR/Cas9-modified cells as part of a clinical trial. While far from the first time a gene-editing therapy has been tested on a human subject, the Chengdu clinical trial could launch a gene-editing "cold war" of sorts between Chinese and American biomedical clinicians—while accelerating gene-editing therapeutics in humans worldwide, with CRISPR leading the way.

The first human clinical trials in the United States to use CRISPR gene-editing technology are anticipated to begin in the next few months; the University of Pennsylvania is manufacturing the edited cells for cancer patients. Meanwhile, a research group at Beijing's Peking University is awaiting approval and funding for three separate CRISPR-based clinical trials of its own—anticipated to begin in March.

“I think this is going to trigger ‘Sputnik 2.0’, a biomedical duel on progress between China and the United States," Carl June, a University of Pennsylvania immunologist who led a 2014 gene-editing study involving testing ZFNs on humans and is currently helping to lead U-Penn's CRISPR cancer-cell research, told Nature, “which is important since competition usually improves the end product.”

Nonetheless, these whims and demands of the free market—despite being the very antithesis to regulation—may simultaneously hold back the hopes and dreams (for the time being, anyway) of those banking of CRISPR technologies, according to Jiang.

“Technology has a development cycle [and an] investment cycle… based on 20-plus years of experience,” said Jiang. “You need to be Wall Street-recognized… Venture capital follows technology.”

CRISPR Revitalizing “Gene Therapy”

Jiang pointed to cases of so-called “gene therapy” clinical trials in 2001 in Philadelphia (involving hemophilia) and Paris (involving x-linked severe combined immunodeficiency, a.k.a. SCID) respectively. Back then, and for years after, gene therapy had trouble attracting investment from venture capitalists—not least of all because Jesse Gelsinger, an 18-year-old liver-disease patient, died in 1999 from the very adenovirus used as the delivery mechanism for a “corrective” gene.

“Before, they called it ‘gene therapy.’ Today you call it ‘gene-editing therapy,’” said Jiang with some nakedly observable measure of sardonic glee. “No VC want[ed] to invest in that area.”

Only in the past couple of years has the 1990s’ trend of gene-therapy research and experimentation begun to make a comeback—thanks in large part to new innovation and CRISPR-driven rebranding of the field. Just as the putative end of gene therapy had a poster child of doom and gloom in the tragically deceased Gelsinger, CRISPR has its own poster child of hope in Ben Dupree, a 24-year-old man with Duchenne muscular dystrophy, who doctors think could one day be cured thanks to CRISPR/Cas9's first Duchenne muscular dystrophy clinical trial for human patients coming in the next couple of years.

What makes Dupree's case different from other human gene-therapy cases is that his genetic lack of dystrophin has been traditionally incompatible with virus-based gene therapies; the gene responsible for dystrophin is too large to fit inside a tiny virus. CRISPR's Cas9 gene-splicing scissors, however, are small enough to fit inside such a virus, and the proof of concept has already been demonstrated with (what else?) lab mice.

Now, as some doctors and pundits have dubbed CRISPR “gene therapy 2.0,” so-called “gene therapy” (i.e., by way of gene editing) has been undergoing a major investment boom—thanks in no small part to CRISPR/Cas9 gene-editing technology.

For instance:

  • A year ago, on the heels of a $65 million Series C round of venture-capital financing, gene therapy Audentes Therapeutics filed for an IPO with the SEC—eventually raising $75 million.
  • Applied StemCell completed a $19 million Series D round this past June. Relatively paltry as the figure may seem, Applied StemCell's Series D was nonetheless an “up” round by an extremely large margin of nearly 720%; its Series C round, in early 2013, garnered but $2.64 million. The company’s Series B saw an infusion of $1.88 million in 2010—back when, according to Applied StemCell's Jiang, et alia, gene therapy was a turnoff to venture capitalists.


These examples are, of course, but a few highlights (and don’t include the hundreds of millions of dollars raised by several “seminal” CRISPR/Cas9 companies embroiled in patent litigation over the technology).

The Market, the Market, and the Market

To be absolutely clear, the lines are blurry at best when distinguishing between “gene therapy” and “gene-editing therapy.” CRISPR touches it all.

Just ask Eric Kmiec, director of the Gene Editing Institute at the Helen F. Graham Cancer Center and Research Institute. Kmiec is also the lead author of “Analyses of point mutation repair and allelic heterogeneity generated by CRISPR/Cas9 and single stranded DNA oligonucleotides,” a study that extensively maps out everything that happens throughout a gene when a CRISPR cut is made—and how oligonucleotides can minimize deleterious (pun unintended) effects.

“[F]or gene therapy, you want a clean cut at a precise spot with minimal fraying, like cutting a ribbon with scissors, so that the ends can re-close,” explained Kmiec in a statement given to Bio-IT World. “CRISPR can leave frayed ends in the DNA. [The oligonucleotide] helps to maintain the cut, like using a Band-Aid to hold the ends together. Without the oligonucleotide, the ends fray and we lose the gene.”

Recent improvements to CRISPR-based gene editing make the technology that much more of a market driver, even as it continues to evolve. Applied StemCell, for instance, proposes that Cas9 ribonucleoprotein (“RNP”) “is the solution to improve CRISPR efficiency, especially in hard to transfect and sensitive cell lines such as the blood lineage cells.”

“The first thing I [am] thinking about is the market,” acknowledged Applied StemCell's Jiang, for all of his cautions about regulators and VC firms. “If there’s a market demand, obviously, we move faster [adopting the technology] than without.”

At the end of the day, CRISPR—for all its uncertainty—retains its crown as king of genomics hype. How long that can remain the case with constant advances in CRISPR technology and competing (or “complementary”) technology is anyone’s guess.

“You have to respect the technology development cycle. I’m very positive [about CRISPR], but you really need to be patient,” said Jiang. “[This is] just the starting time for gene-editing technology... Once you have a breakthrough, more people [and] more resources move in that direction.”

* Discovery on Target, Cambridge Healthtech Institute, September 19-22, Boston, Mass.