biomedical research

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Nobel art of science

Santiago Ramón y Cajal’s drawings lay out the brain in surprising detail—and beauty.

“An entire universe that has scarcely been explored lies before the scientist… Each cell presents us with the unknown, and each heartbeat inspires profound meditation within us.”

He grew up in poor Spanish hill towns near the French border, bright, impulsive, strong-willed, prone to escapades that have more than a touch of the medieval. He was endlessly curious, experimental, energetic, determined to think things through by himself. By eight years old he was drawing incessantly wherever he could, coloring his drawings with paint flaked from walls, bitterly opposed by his doctor father. He was a famously disobedient student, often beaten by teachers, once locked up by himself for more than a day. His father pulled him out of school and apprenticed him to a shoemaker for a year. He was an enthusiast and expert for drawing, painting, birds, nature walks, wooden cannons he built himself. Years later, he plunged deeply into gymnastics, chess, gymnastics, philosophy, hypnotism and whatever else caught his interest. When he grew excited by photography, he not only taught himself excellent shooting skills but developed emulsions for developing prints that were better than what he could buy. He and his father stole bones from a graveyard to help their anatomy studies. He joined the Spanish army as it fought rebellions at home and in Cuba. He survived malaria and then tuberculosis.

Such was the education of Santiago Ramón y Cajal, who became the world’s greatest neuroscientist.

He won the Nobel Prize in 1906 and is best known for his theory that nerve cells in the brain are not directly wired together but connected by chemicals—a theory not confirmed until the electron microscope debuted, decades later. He possessed an astonishing intuition for guessing at brain function based on structure, backed by an astonishing amount of hard work to reveal that structure. He couldn’t afford a good microscope until he was given one for his help in a cholera epidemic. He taught himself German, the language of biomedical science, to keep in touch with the latest findings. He published his own scientific journal when it was the only way to spread his own discoveries, which were numerous and major.

Perhaps most famously, Ramón y Cajal presented what he saw in the brain in thousands of drawings that elegantly show the brain’s wild menageries under the microscope, artwork that is stunningly created to emphasize structure and concepts. You can now see 80 of these masterpieces in the well-received Beautiful Brain exhibition at the MIT Museum.

Ramón y Cajal lived in a very different time—for instance, his autobiography has nothing but good to say about his wife but never mentions her name. He was not just genius but appealing human being. He was thoughtful, kind, wryly humorous, sociable, patient with others, resourceful, surprisingly tough, endlessly curious.  He wrote superbly on science and his own remarkable life. His aphorisms are still quoted. His lessons still stand.

“Drawing enhances discipline and attention, for it forces us to observe the totality of the phenomenon and see details overlooked in ordinary observation.”

“In our parks are there any trees more elegant and luxurious than the Purkinje cell from the cerebellum?”

“Nature is a harmonious mechanism where all parts, including those appearing to play a secondary role, cooperate in the functional whole.”

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Celling out cancer

As immunotherapies start to change clinical practice, we hope for more.

CI_cover_crop

For a blockbuster drug, pembrolizumab comes with a strange history, nicely told here by David Shaywitz.

Pembro is a “checkpoint inhibitor”, a biologic designed to take the brakes off T cells so that they can wipe out tumors. Back in 2014, it was the first drug that targets the PD-1 protein on the surface of T cells to get FDA approval. Also now known as Keytruda, pembro has received FDA green lights for many kinds of cancers. It accounts for billions of dollars each year and is in more than 500 clinical studies.

But it was born in a small Israeli biotech trying to develop treatments for autoimmune diseases by putting brakes on T cells (yes, the reverse of checkpoint inhibition).  The small biotech that created pembro and realized it was a promising cancer drug candidate was soon bought by a larger pharma firm, which was then acquired by Merck & Co. As Shaywitz notes, the giant pharma shut down development not once but twice, before successful trials of other checkpoint inhibitors changed its mind.

Today pembro comes as a colorless liquid in a small IV pouch, looking very much like saline solution. It lists at around $50 a milligram, one case in point for the extremely real concern about how any country can pay for such drugs as they start to become standard of care.

You don’t think about costs, however, if you’re in a clinic as I was earlier this month, watching a friend with metastatic melanoma joke with the nurse hooking up his IV. You just hope the treatment works.

It’s been a pleasure to edit this month’s Nature Outlook on cancer immunotherapy. Many thanks to the outstanding authors, editors and designers who put it together! And to Elin Svensson, who created the great cover art above.

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Blossoms in biomedicine

The remarkable global push for cancer immunotherapies.
El_Talayón.byJose Ignacio Martinez Navarro
Editing a Nature special report on cancer immunotherapies, I’m struck most by the sheer scale of the development effort. Something like 3,000 clinical trials are underway, 800 of them combining treatments. The FDA has approved five checkpoint inhibitors, designed to unleash T cells against tumors. The agency seems close to approving the first CAR-T cell treatment, in which a patient’s T cells are removed, reengineered to attack cancer cells, regrown in volume and returned to the patient. Old dogs of immunotherapies are learning new tricks. Some newer approaches are getting much attention—notably personalized neoantigen vaccines, in which individual tumors are sequenced to give clues on how to best target their unique sets of immune-system-alarming antigens. Some clinical trials fail, some do surprisingly well.  The competition is more than intense and trials are not always carefully planned or analyzed. But the landscape is changing.

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Moving the needles

Updates on progress in research against type 1 diabetes.

BetaBionics

JDRF New England’s annual research briefing offers a quick summary of research for type 1 diabetes. Here are four snapshots from last night’s talks by JDRF’s Julia Greenstein and University of Colorado’s Peter Gottlieb:

  1. The march continues toward an “artificial pancreas” that automatically provides just the right amounts of insulin around the clock. The first of four NIH-sponsored pivotal clinical trials kicked off in February. Many of us are most intrigued by the Beta Bionics combo device, designed to deliver both insulin (which lowers blood glucose levels) and glucagon (which raises them). This device is a few years behind some of its competitors, but we like it for the same reason we would prefer a self-driving car with brakes.
  1. JDRF has awarded more than 50 grants for research on encapsulating insulin-producing beta cells derived from stem cells, to initiatives such as the Boston Autologous Islet Replacement Therapy Program. News from the much-watched Viacyte clinical trial, however, is not so good. The Viacyte capsule prevents against some immune response but generates a foreign-body reaction. Next–generation encapsulation technologies may do better on immune response but must still grapple with another fiendishly tricky issue—admitting suitably high levels of oxygen to the beta cells. (The pancreas is even hungrier for oxygen than the brain, Greenstein noted.)
  1. For decades, immunologists in both cancer and autoimmune diseases like type 1 diabetes made important discoveries that didn’t translate into better treatments. That unhappy situation has changed bigtime with cancer immunology, and diabetes researchers are now adopting two general strategies in cancer treatment. One strategy is to recognize that the disease may work quite differently in different people—for example, in trials of drugs designed to delay or prevent progression of the disease, often one group responds much better than another. So “personalized medicine”, tailored to specific groups of patients, may recast the field in type 1 just as it has done with many forms of cancer. The second strategy aims to confront the complexity of the disease by combining treatments, as the University of Miami’s Jay Skyler has proposed.
  1. No clear winners have ever emerged from the dozens of trials of drugs designed to delay or prevent type 1 diabetes onset. One contender that’s still standing is oral insulin acting as a vaccine. Drug companies have chased the elusive goal of an insulin pill for a century (with a few recent signs of progress) but such pills typically get ripped apart in your gut without lowering your blood glucose levels. However, the resulting fragments of insulin may generate an anti-immune protective response in the pancreas. Early clinical tests of this vaccine concept (such as this one reported in 2015) have shown promise for some patients. The latest clinical results, including early findings from a phase II trial with higher doses, will be announced on June 12th at the American Diabetes Association annual scientific sessions. We’ll be watching!
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Clean genes

Twenty years on, James Wilson’s vision is redeemed.

aav_3-02017 probably will be the year in which gene therapies will be first approved by the Food and Drug Administration—a positive move in a year that’s not looking so positive overall.

These successes were built in part on experience from a tragic clinical failure back in 1999, with the death of a teenage volunteer in the far-too-aggressive early gene therapy trial spearheaded by James Wilson of the University of Pennsylvania.

“This event had far-reaching effects on the trajectory of gene therapy research and oversight of all clinical trials,” Wilson noted a decade later in a commentary on lessons learned.

“My deepest regret is that a courageous young man who agreed to participate in this clinical trial with the hope of making life better for others with this disease lost his life in the process,” he wrote. “The immunologic response that precipitated the lethal syndrome of systemic inflammation was unanticipated and not predicted based on the preclinical and clinical data available at the time. However, some of the problems in the design and conduct of the clinical trial that surfaced in the subsequent investigations were real and absolutely unacceptable and ultimately were my responsibility.”

Wilson lost his government research funding. But with initial backing from a former mentor at GlaxoSmithKline, he went back into the lab to develop more advanced gene therapy delivery systems,  “adeno-associated” virus (AAV) vectors, that are a cornerstone of many therapies now approaching approval.

“We characterized these vectors and started to distribute them to academic researchers,” Wilson told me last year for a story in Nature. “Over the next 10 to 15 years, these vectors have formed the basis for most of the clinical translation and most of the companies that have been founded.”

One of these companies is Spark Therapeutics, whose treatment for a rare genetic eye disease may be the first gene therapy to get FDA approval. Spark also is among several biotechs with candidates for treating hemophilia that appear both surprisingly effective and, so far, acceptably safe.

True, no one really knows if the effects of these new therapies will last a lifetime. Or exactly how payers will view their high prices.

“If we can deliver transformative therapies, we’ll see huge effects on the practice of medicine,” said Wilson, who is now leading the creation of a third generation of AAV vectors (above). “The concept is so fundamental: engineering a cell to modify expression of a gene to prevent, cure or treat a disease. This will only grow.”

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Beta living through stem cells

Insulin-producing cells will be tested first in patients lacking a pancreas.

insulin

Diabetes is way complex. “But it’s a simple disease conceptually—your body doesn’t produce enough insulin,” notes Joslin Diabetes Center researcher Gordon Weir.

In type 1 diabetes, an autoimmune attack wipes out insulin-producing beta cells, which are found in clusters of pancreatic cells called islets. In type 2 diabetes, the beta cells are still there but not hauling all the freight. That disease can be treated with many other types of drugs, along with lifestyle changes. But over time, beta cells wear out. In fact, more people with type 2 take insulin than people with type 1.

And there’s no way to make insulin injections pleasant or easily controllable or as good as insulin production by beta cells.

Thus the huge interest in a long-term research project spearheaded by Harvard’s Doug Melton to create working beta cells by manipulating stem cells. An update on the ambitious project from Melton, Weir and other partners drew a crowd at Harvard on Monday.

Making insulin-producing cells good enough for clinical trials “turns out to be rather difficult; it took more than a decade,” Melton said. “We haven’t made it really perfect, but it’s at the goal line.”

Technology from Melton’s lab has been licensed exclusively to the startup Semma Therapeutics, which is joining with Joslin, Brigham & Women’s Hospital and Dana-Farber Cancer Institute to move toward clinical trials. Traveling under the ungainly title of the Boston Autologous Islet Replacement Therapy Program (BAIRT), the collaboration launched in June.

The first BAIRT studies, starting at least three years from now, will not be among people with type 1 diabetes. Instead, they will recruit people who have had their pancreases removed, usually because of uncontrollable pain after the organs are chronically inflamed by years of heavy drinking.

This approach bypasses the biggest problem in cell treatments for type 1 diabetes: the body renews its autoimmune attack and wipes out the newly introduced cells. “We decided to solve one problem at a time,” Melton explained.

Patients who have prostatectomies often now are given islet cells salvaged from their own pancreas, which helps to improve their diabetes control, but those cells may themselves be damaged or in short supply, said Brigham surgeon Sayeed Malek. Transplants of brand-new beta cells, made from the patients’ own blood, should help.

These reengineered cells will be injected in the arm, where they will be easy to monitor  and to remove if necessary, said Semma CEO Robert Millman. Decades of experience transplanting cells from cadavers has shown that “you can put beta cells just about anywhere,” Weir added.

Against autoimmunity. If all goes well, the project will continue into trials for type 1 diabetes with non-personalized beta cells, where the autoimmune attack will be blunted via encapsulating the cells. Seema is spending about half its budget on encapsulation technologies, Millman said.

Encapsulation is the near-term solution to fend off the autoimmune attack. “The long-term solution is to use the power of biology to understand why the immune system has made this mistake,” Melton remarked.

He briefly mentioned two promising research thrusts. One effort is to learn from the rapid advances in knowledge about how cancer cells dodge the immune system.

Another, led by Chad Cowan of Massachusetts General Hospital, aims to create a “universal donor pluripotent stem cell.” Missing all the billboard signs that alert immune enforcers, these cells could play a role like that of O-positive cells in blood transfusions.

Asked about his own take on the causes of type 1, Melton mentioned one theory that the autoimmune attack may be triggered by gut cells that naturally produce insulin or similar substances under certain conditions.

Slow and steady. Bringing beta cell therapies to the clinic will be a marathon march with not only many scientific steps but many regulatory steps. Millman emphasized, however, that “the FDA is working with us very early on the regulatory path.”

Among potential safety risks, all stem cell therapies must be carefully vetted to avoid the growth of teratomas—tumors with a jumbled mix of cells, usually benign. These cellular junk piles would be relatively easy to remove, but much better to avoid altogether, Millman said.

Another concern is that the cells will secrete insulin even when it’s not needed, dropping the recipient’s blood sugar levels to dangerously low levels.

There also is much cause for worry that the cells won’t last long, a major problem in transplants of cadaver beta cells. However, built-from-scratch cells function “for more than a year in mice, which bodes well for people,” Weir commented. And Millman pointed out that the cells resemble juvenile cells, which may help them withstand the high stresses of transplantation better than worn-out adult beta cells do. “We hope these almost pristine cells going into the patients will last a lot longer,” he said.

None of this will come cheap. Asked about pricing for cell therapies, way down the road when and if they hit the market, Millman was understandably wary. Initial costs for these treatments will be very high, accompanied by very close regulatory scrutiny. Semma has raised about $50 million, but “we need philanthropy and we need institutions to support this,” he said.

Melton suggested, though, that successful cell-based therapies will make complete  economic sense, given the soaring numbers of people with diabetes and the huge costs of diabetes care. Each year the world spends about $30 billion on insulin alone. “Diabetes is not an orphan disease,” he said. “The cost will come down very quickly.”

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Unlocking the combinations

tsMouse regulatory T cell and human T cell, courtesy NIAID.

The autoimmune attack that triggers type 1 diabetes has been beaten in the non-obese diabetic mouse, the best animal model of the disease.

More than 500 times, in fact, notes Jay Skyler, professor of medicine at the University of Miami.

But in humans: never.

Researchers have painstakingly picked apart the genetics of the disease and many of the intricacies of the immune attack that wipes out insulin-creating cells in the pancreas. And recent studies suggest that we might, just might, have a smoking gun in the form of disease-triggering populations of gut microbes. But we don’t really know the trigger mechanisms and we really can’t stop the disease.

However, as Skyler reviewed the disappointing decades of type 1 trials in a lecture last week at Joslin Diabetes Center, he pointed out research approaches that might lead closer to a cure.

Among them: examining the effects of treatments by subgroups (such as age), coordinating dosing with the timing of immune events, and administering multiple doses or higher doses of a drug.

Given the unending complexity of the immune system, though, maybe the most promising strategy is to hit it at multiple points. That’s the thinking behind Skyler’s upcoming Diabetes Islet Preservation Immune Treatment (DIPIT) trial.

DIPIT will compare two groups of people recently diagnosed with type 1, one group given five drugs and the other a placebo. The drugs, all giving hints of helpfulness in earlier type 1 trials and approved by the Food and Drug Administration for other conditions, are

• anti-thymocyte globulin (an antibody used to prevent rejection in organ transplants)
• etanercept (which inhibits tumor necrosis factor, a master regulator of immune response)
• pegylated granulocyte colony stimulating factor (a growth factor that boosts production of certain white blood cells)
• Interleukin 2 (a cytokine whose effects include increasing growth of the regulatory T cells that can guard against autoimmune onslaughts), and
• exenatide (a synthetic hormone that boosts glucose-dependent insulin secretion).

As Skyler told the Miami Herald, “we have one drug to stop the cavalry; one drug to stop the artillery; two drugs that help bring in support systems that favor the immune response; and one drug that helps beta cell health so they can resist the attack better.”

When he first proposed this kitchen-sink idea, “everybody said I was crazy,” Skyler remarked to his Joslin audience. The trial did get FDA approval. He’s still looking for funding, though.

Okay, let’s contrast these combinations with those in another arena of biomedical research that’s almost the reverse of type 1: cancer immunotherapy.

This field tries to activate (rather than suppress) the immune system at multiple points. Also unlike the case with type 1 and other autoimmune diseases, it is awash in drug-discovery money.

In fact, we’re living in the breakthrough decade for cancer immunotherapy. The two clear winners so far are CAR-T cells (chimeric antigen receptor T cells, in which a patient’s own cells are re-engineered to seek and destroy blood cells gone bad) and checkpoint blockade drugs (which prevent tumors from presenting false IDs).

The first checkpoint blockade drug approved by the FDA targets CTLA-4, a surface receptor on T cells and B cells. About a fifth of advanced melanoma patients given the drug survive for ten years with no further treatment. And in clinical trials, combining a CTLA-4 inhibitor with a drug that clogs up another checkpoint receptor, PD-1, has significantly broadened the population of survivors.

Combination is a familiar theme in cancer treatment, since tumors are so adept at evolving to resist whatever you throw at them. There are very high hopes for adding immunotherapies to the mix.

And in that mix, proven treatments like checkpoint blockaders will be joined by other drugs that hit different points of immune activation. There’s much excitement, for instance, about agents that activate the STING (stimulator of interferon genes) pathway, which can kick off defenders in both the innate and the adaptive immune systems and maybe act as a kind of cancer vaccine.

In both cancer and diabetes, nothing will be easy in bringing combination therapies into clinical trials and then ideally into regular practice. Researchers must identify exactly which patients might benefit from which combos, juggle drug dosages and timing, watch for serious side effects and struggle to quantify any improvements in health. These will be long rough roads. But for some patients, we hope, combos will lead to cures.