Now CRISPR targets MPN genes.
Suddenly, there was hope, a fresh approach to treat disease that might apply to MPNs. Now there was a technology coming out of the biology labs that would no longer rely on putting out fires downstream of the blaze. This technology promised the possibility of correcting mutations that cause the conflagration of myeloproliferative neoplasm at their very source.
In a report of that meeting with Jennifer Doudna there’s a photograph of her holding a photo model of the CRISPR/Cas9 molecule on her phone. She’s seated before a computer monitor displaying the CRISPR story on an MPN web page. We had been talking about MPNs and gene editing.
It may not have been the first time an MPN patient and editor sat down with a CRISPR/Cas9 scientist to explore therapeutic possibilities. For both of us, however, it was a first deep exposure of the other’s world. Inspired by Jennifer Doudna’s commitment to collaboration, the possibility of joining our two worlds became a reality.
It was the beginning of a four month crusade to help bring gene editing into the treatment options our hematologists could offer us.
…but first, Chicago
Before it could happen, we had to go to the fountainhead of MPN research. Just weeks after picking up that parking lot pass, I went to Chicago to visit the MPN Research Foundation to get its endorsement and support.
That was the beginning. Here’s how it ended:
Now that the gods of Spring are smiling softly down on us, the brutal winter of 2015 is not only forgiven but forgotten. Almost. Reporting on the pair of historic gene editing meetings that took place in the Boston area this winter – the Hanson-Wade and IBC meetings – the chill winter blasts invade my notes, tapes and photos.
The meetings featured CRISPR pioneers, academic and developer labs shaping the DNA of the path gene editing is likely to take. But when it came time to sort out all the notes of interviews and presentations, one image kept intruding. Driving in a sudden blizzard.
The mid-March IBC Genome Editing Applications meeting at the Hilton Boston would have been remarkable enough without the accompaniment of global climate changes funneling into Boston’s Back Bay. Somehow it all made sense: Fundamental meteorological change as the background to the radically disruptive and transformative nature of the new biotechnology. The reality was a lot scarier.
On the first day of Spring, Interstate 495 in Massachusetts was a slippery ghost of a road covered in sliding sheets of snow. In the early morning white-out, lane markers emerged and vanished as the snow slid across the highway driven by strong wind gusts.
I was headed to Logan Airport, following the black tire tracks and red taillights of cars fishtailing ahead of me. Two days earlier, a freak prolonged wind event,with gusts up to 75 miles per hour, packed with claws of ice, had pinned me against a parked car outside the Sheraton, just a few yards from the unreachable IBC meeting site.
All of it, struggling against prevailing winds, following in the tire tracks of winter-hardened Boston drivers opening a path into unknown territory, may have been more Fellini than Isaac Newton but that’s how this story actually came together. Reporting doesn’t always take place on the phone while googling at a warm desk with a cup of coffee by your side.
The IBC gene editing meeting – focused on CRISPR/Cas9 – documented the extraordinary progress of a revolution started less than three years ago. The winds of change had already blown apart perceived limitations on human ability to modify the genome – quickly, cheaply, easily, and efficiently. Now, despite unclear boundaries, intense efforts were underway to improve targeting and delivery systems on the road from laboratory to clinic.
One after another, Speakers rose to report on progress in CRISPR/Cas9 applications in cardiovascular design, blood disorders, nucleic acid delivery systems, drug discovery and validation systems and new means to rejigger the genome and epigenome through gene editing.
She helped introduce us to CRISPR back in November, the MPNforum issue with the giant e-coli bug on the Home Page. Heading out to the coffee bar during a break, there she was.
I wasn’t sure if it was appropriate to ask her for an autograph but I settled for her photo. She’s Namritha Ravinder, Staff Scientist at ThermoFisher.
At least three of the people who played a role in opening the Pandora’s box of gene editing were featured at the meeting: George Church, professor of genetics at Harvard and MIT, Rachel Haurwitz, head of Caribou Biosciences, and Feng Zhang, the Broad Institute of Harvard and MIT. At one point, the legendary George Church took time out to fiddle with my dysfunctional handycam. And sign a copy of his book, Regenesis (strongly recommended).
The approximately 150 registrants at the meeting, most of whom were active in academic or commercial gene editing labs, were starkly different from those who participate in clinical meetings like the annual American Society of Hematology events. Beyond focus, the new genetic editing population was different from ASH attendees in other respects as well. As expected, there were few MDs and many PhDs, more academics than clinicians, a much higher fraction of women than seen at ASH, and, above all, extraordinary youth. (Two of our featured pioneers are barely out of their twenties.)Invariably polite and interested in our clonal mutant disease, nobody appeared to have heard of myeloproliferative neoplasms
The immediate role of CRISPR/Cas9 may be as a tool to improve the efficiency of CAR-T and other Adoptive Cell Transfer immunotherapies.
Putting the CART before the CRISPR
CAR-T requires engineering the body’s own T cells – the basic infantry of the immune system — to express Chimeric Antigen Receptors (CARS) able to recognize cancer targets on cells. Gene editing is used to modify T cells and link to viral vectors to integrate the CAR-Ts into the cell’s DNA. Immediate and dramatic results have been reported in early ALL trials. CRISPR/Cas 9 has the ability to refine and simplify development of CAR-Ts. Now in Phase 2 clinical trial, CAR-Ts are widely expected to apply for INDs in 2016.
And that’s not the only immediate role for CRISPR in human clinical application. This week, The Whitehead Institute in the biomedical supercluster around MIT, announced its use of CRISPR/Cas9 to target killer fungal infections. Gerald Fink, Whitehead founder and a professor of biology at Harvard said, The ability to engineer Candida albicans with CRISPR technology has changed the playing field. We used to attack this human pathogen with our hands tied behind our back. Our findings cut these bonds, freeing us to forge ahead on problems in basic research and human health.”
While the short term clinical application of CRISPR/Cas9 may be as a supplement to the genetic engineer’s toolbox and in a supporting role for the CAR-Ts the transformative therapeutic payoff of CRISPR lies in direct repair of genetic mutation.
First in the queue
Big money, major drug firm collaboration, and professional reputations are all on the line in the race for successful clinical application of CRISPR. And in that race, the low-hanging fruit is the single loss-of-function mutations that cause deadly diseases like Sickle Cell Anemia and Cystic Fibrosis.
Scientific and clinical research at both Boston-area meetings – Hanson Wade and IBC — clearly demonstrated the rapid pace of bioengineering since introduction of CRISPR less than three years ago in the expansion of journal publications and proliferation of commercial development work.
The focus of most CRISPR research is on improving target specificity and delivery systems — part of which involves speeding up the intracellular editing process — and evaluating and sharing editing outcomes. Alternate delivery systems – using plasmids, viruses, oligonucleotides, electroporation and direct delivery to the cell of a modified protein with the DNA molecule—were highlighted. Presentations were made on applying the accuracy of double strand breaks to single strand cleavage — of special interest in MPN patients who are heterozygous for the JAK2 mutation.
There seemed to be a general sense that human clinical CRISPR applications were likely within the next two years. Both the FDA and NIH were represented and presented options to help investigators in the IND process. CR-T and other immunotherapies in which CRISPR plays a supportive role are expected to be approved next year.
First direct CRISPR targets are likely to be the single cell loss of function mutations causing, for example, Sickle Cell Anemia and Cystic Fibrosis. These are applications where repair of the defective cell ex vivo followed by expansion of the edited colony and reintroduction is likely to produce immediate benefit with minimal risk.
George Church’s lab at Harvard and MIT is working on getting systemic delivery incorporated at the genomic level for a variety of cell types including hematopoietic cells. He referred to the gene conversion work presented by Editas, repairing a defective homolog with the correct one, as one option “The issue here may be a competing non-homologous end joining (NHEJ) reaction but if cleavage is site specific we can get a mix of cells repaired to the correct allele and others, if they were heterozygous in the first place, would be hemizygous. “
Church is well aware of the challenge of proliferative diseases where you can wipe out 99% of mutated cells but, in principle, the mutant clone can rebound. He noted the various mutations identified in MPNs are something the CRISPR Cas9 system with multiple targeting capabilities is well positioned to address. Church noted various ways cells can be switched on, expanded, switched off, inserted.
Ex vivo selection, repair and reintroduction seems the preferred route for now. The ex vivo route permits increased efficiency through some sort of selective process, an ability to screen and expand a population of cells before reintroduction.
His lab, as all the researchers we talked with, is open to collaboration with clinicians. His and Feng Zhang’s lab at MIT may not yet have much MPN experience available but they have the Harvard Medical School clinicians available. Other academic research with deep CRISPR credentials need clinical collaborators to bring gene editing to MPNs.