New drug for schizophrenia could meet desperate need for better treatments
Schizophrenia is a debilitating mental health condition that affects around 24 million people worldwide. Patients experience hallucinations and delusions when they develop schizophrenia, with experts referring to these new thoughts and behaviors as positive symptoms. They also suffer from negative symptoms in which they lose important functions, suffering from dulled emotions, lack of purpose and social withdrawal.
Currently available drugs can control only a portion of these symptoms but, on August 8th, Karuna Therapeutics announced its completion of a phase 3 clinical trial that found a new drug called KarXT could treat both positive and negative symptoms of schizophrenia. It could mean substantial progress against a problem that has stymied scientists for decades.
A long-standing problem
Since the 1950s, antipsychotics have been used to treat schizophrenia. People who suffer from it are thought to have too much of a brain chemical called dopamine, and antipsychotics work by blocking dopamine receptors in the brain. They can be effective in treating positive symptoms but have little impact on the negative ones, which can be devastating for a patient’s quality of life, making it difficult to maintain employment and have successful relationships. About 30 percent of schizophrenia patients don't actually respond to antipsychotics at all. Current drugs can also have adverse side effects including elevated cholesterol, high blood pressure, diabetes and movements that patients cannot control.
The recent clinical trial heralds a new treatment approach. “We believe it marks an important advancement for patients given its new and completely different mechanism of action from current therapies,” says Andrew Miller, COO of Karuna.
Scientists have been looking to develop alternatives. However, “the field of drug treatment of schizophrenia is currently in the doldrums,” says Peter McKenna, a senior researcher at FIDMAG Research Foundation in Spain which specialises in mental health.
In the 2000s there was a major push to target a brain receptor for a chemical called glutamate. Evidence suggested that this receptor is abnormal in the brains of schizophrenia patients, but attempts to try glutamate failed in clinical trials.
After that, many pharmaceutical companies dropped out of the race for a more useful treatment. But some companies continued to search, such as Karuna Therapeutics, led by founder and Chief Operating Officer Andrew Miller and CEO Steve Paul. The recent clinical trial suggests their persistence has led to an important breakthrough with their drug, KarXT. “We believe it marks an important advancement for patients given its new and completely different mechanism of action from current therapies,” Miller says.
How it works
Neurotransmitters are chemical messengers that pass signals between neurons. To work effectively, neurotransmitters need a receptor to bind to. A neurotransmitter called acetylcholine seems to be especially important in schizophrenia. It interacts with sites called muscarinic receptors, which are involved in the network of nerves that calm your body after a stressful event. Post mortem studies in people with schizophrenia have shown that two muscarinic receptors in the brain, the M1 and M4 receptors, are activated at unusually low levels because they don’t receive enough signals from acetylcholine.
The M4 receptor appears to play a role in psychosis. The M1 receptor is also associated with psychosis but is primarily thought to be involved in cognition. KarXT, taken orally, works by activating both of these receptors to signal properly. It is this twofold action that seems to explain its effectiveness. “[The drug’s] design enables the preferential stimulation of these muscarinic receptors in the brain,” Miller says.
How it developed
It all started in the early 1990s when Paul was at pharmaceutical company Eli Lilly. He discovered that Xanomeline, the drug they were testing on Alzheimer's patients, had antipsychotic effects. It worked by stimulating M1 and M4 receptors, so he and his colleagues decided to test Xanomeline on schizophrenia patients, supported by research on the connection between muscarinic receptors and psychosis. They found that Xanomeline reduced both positive and negative symptoms.
Unfortunately, it also caused significant side effects. The problem was that stimulating the M1 and M4 receptors in the brain also stimulated muscarinic receptors in the body that led to severe vomiting, diarrhea and even the temporary loss of consciousness.
In the end, Eli Lilly discontinued the clinical trials for the drug, but Miller set up Karuna Therapeutics to develop a solution. “I was determined to find a way to harness the therapeutic benefit demonstrated in studies of Xanomeline, while eliminating side effects that limited its development,” Miller says.
He analysed over 7,000 possible ways of mixing Xanomeline with other agents before settling on KarXT. It combines Xanomeline with a drug called Trospium Chloride, which blocks muscarinic receptors in the body – taking care of the side effects such as vomiting – but leaves them unblocked in the brain. Paul was so excited by Miller’s progress that he joined Karuna after leaving Eli Lilly and founding two previous startups.
“It's a very important approach,” says Rick Adams, Future Leaders Fellow in the Institute of Cognitive Neuroscience and Centre for Medical Image Computing at University College London. “We are in desperate need of alternative drug targets and this target is one of the best. There are other alternative targets, but not many are as close to being successful as the muscarinic receptor drug.”
Clinical Trial
Following a successful phase 2 clinical trial in 2019, the most recent trial involved 126 patients who were given KarXT, and 126 who were given a placebo. Compared to the placebo, patients taking KarXT had a significant 9.6 point reduction in the positive and negative syndrome scale (PANSS), the standard for rating schizophrenic symptoms.
KarXT also led to statistically significant declines in positive and negative symptoms compared to the placebo. “The results suggest that KarXT could be a potentially game-changing option in the management of both positive and negative symptoms of schizophrenia,” Miller says.
Robert McCutcheon, a psychiatrist and neuroscientist at Oxford University, is optimistic about the side effects but highlights the need for more safety trials.
McKenna, the researcher at FIDMAG Foundation, agrees about the drug’s potential. “The new [phase 3] study is positive,” he says. “It is reassuring that one is not dealing with a drug that works in one trial and then inexplicably fails in the next one.”
Robert McCutcheon, a psychiatrist and neuroscientist at Oxford University, said the drug is an unprecedented step forward. “KarXT is one of the first drugs with a novel mechanism of action to show promise in clinical trials.”
Even though the drug blocks muscarine receptors in the body, some patients still suffered from adverse side effects like vomiting, dizziness and diarrhea. But in general, these effects were mild to moderate, especially compared to dopamine-blocking antipsychotics or Xanomeline on its own.
McCutcheon is optimistic about the side effects but highlights the need for more safety trials. “The trial results suggest that gastrointestinal side effects appear to be manageable,” he says. “We know, however, from previous antipsychotic drugs that the full picture regarding the extent of side effects can sometimes take longer to become apparent to clinicians and patients. Careful ongoing assessment during a longer period of treatment will therefore be important.”
The Future
The team is currently conducting three other trials to evaluate the efficacy and long-term safety of KarXT. Their goal is to receive FDA approval next year.
Karuna is also conducting trials to evaluate the effectiveness of KarXT in treating psychosis in patients suffering from Alzheimer’s.
The big hope is that they will soon be able to provide a radically different drug to help many patients with schizophrenia. “We are another step closer to potentially providing the first new class of medicine in more than 50 years to the millions of people worldwide living with schizophrenia,” says Miller.
How Can We Decide If a Biomedical Advance Is Ethical?
"All fixed, fast-frozen relations, with their train of ancient and venerable prejudices and opinions, are swept away, all new-formed ones become antiquated before they can ossify. All that is solid melts into air, all that is holy is profaned…"
On July 25, 1978, Louise Brown was born in Oldham, England, the first human born through in vitro fertilization, through the work of Patrick Steptoe, a gynecologist, and Robert Edwards, a physiologist. Her birth was greeted with strong (though not universal) expressions of ethical dismay. Yet in 2016, the latest year for which we have data, nearly two percent of the babies born in the United States – and around the same percentage throughout the developed world – were the result of IVF. Few, if any, think of these children as unnatural, monsters, or freaks or of their parents as anything other than fortunate.
How should we view Dr. He today, knowing that the world's eventual verdict on the ethics of biomedical technologies often changes?
On November 25, 2018, news broke that Chinese scientist, Dr. He Jiankui, claimed to have edited the genomes of embryos, two of whom had recently become the new babies, Lulu and Nana. The response was immediate and overwhelmingly negative.
Times change. So do views. How will Dr. He be viewed in 40 years? And, more importantly, how should we view him today, knowing that the world's eventual verdict on the ethics of biomedical technologies often changes? And when what biomedicine can do changes with vertiginous frequency?
How to determine what is and isn't ethical is above my pay grade. I'm a simple law professor – I can't claim any deeper insight into how to live a moral life than the millennia of religious leaders, philosophers, ethicists, and ordinary people trying to do the right thing. But I can point out some ways to think about these questions that may be helpful.
First, consider two different kinds of ethical commands. Some are quite specific – "thou shalt not kill," for example. Others are more general – two of them are "do unto others as you would have done to you" or "seek the greatest good for the greatest number."
Biomedicine in the last two centuries has often surprised us with new possibilities, situations that cultures, religions, and bodies of ethical thought had not previously had to consider, from vaccination to anesthesia for women in labor to genome editing. Sometimes these possibilities will violate important and deeply accepted precepts for a group or a person. The rise of blood transfusions around World War I created new problems for Jehovah's Witnesses, who believe that the Bible prohibits ingesting blood. The 20th century developments of artificial insemination and IVF both ran afoul of Catholic doctrine prohibiting methods other than "traditional" marital intercourse for conceiving children. If you subscribe to an ethical or moral code that contains prohibitions that modern biomedicine violates, the issue for you is stark – adhere to those beliefs or renounce them.
If the harms seem to outweigh the benefits, it's easy to conclude "this is worrisome."
But many biomedical changes violate no clear moral teachings. Is it ethical or not to edit the DNA of embryos? Not surprisingly, the sacred texts of various religions – few of which were created after, at the latest, the early 19th century, say nothing specific about this. There may be hints, precedents, leanings that could argue one way or another, but no "commandments." In that case, I recommend, at least as a starting point, asking "what are the likely consequences of these actions?"
Will people be, on balance, harmed or helped by them? "Consequentialist" approaches, of various types, are a vast branch of ethical theories. Personally I find a completely consequentialist approach unacceptable – I could not accept, for example, torturing an innocent child even in order to save many lives. But, in the absence of a clear rule, looking at the consequences is a great place to start. If the harms seem to outweigh the benefits, it's easy to conclude "this is worrisome."
Let's use that starting place to look at a few bioethical issues. IVF, for example, once proven (relatively) safe seems to harm no one and to help many, notably the more than 8 million children worldwide born through IVF since 1978 – and their 16 million parents. On the other hand, giving unknowing, and unconsenting, intellectually disabled children hepatitis A harmed them, for an uncertain gain for science. And freezing the heads of the dead seems unlikely to harm anyone alive (except financially) but it also seems almost certain not to benefit anyone. (Those frozen dead heads are not coming back to life.)
Now let's look at two different kinds of biomedical advances. Some are controversial just because they are new; others are controversial because they cut close to the bone – whether or not they violate pre-established ethical or moral norms, they clearly relate to them.
Consider anesthesia during childbirth. When first used, it was controversial. After all, said critics, in Genesis, the Bible says God told Eve, "I will greatly multiply Your pain in childbirth, In pain you will bring forth children." But it did not clearly prohibit pain relief and from the advent of ether on, anesthesia has been common, though not universal, in childbirth in western societies. The pre-existing ethical precepts were not clear and the consequences weighed heavily in favor of anesthesia. Similarly, vaccination seems to violate no deep moral principle. It was, and for some people, still is just strange, and unnatural. The same was true of IVF initially. Opposition to all of these has faded with time and familiarity. It has not disappeared – some people continue to find moral or philosophical problems with "unnatural" childbirth, vaccination, and IVF – but far fewer.
On the other hand, human embryonic stem cell research touches deeper issues. Human embryos are destroyed to make those stem cells. Reasonable people disagree on the moral status of the human embryo, and the moral weight of its destruction, but it does at least bring into play clear and broadly accepted moral precepts, such as "Thou shalt not kill." So, at the far side of an individual's time, does euthanasia. More exposure to, and familiarity with, these practices will not necessarily lead to broad acceptance as the objections involve more than novelty.
The first is "what would I do?" The second – what should my government, culture, religion allow or forbid?
Finally, all this ethical analysis must work at two levels. The first is "what would I do?" The second – what should my government, culture, religion allow or forbid? There are many things I would not do that I don't think should be banned – because I think other people may reasonably have different views from mine. I would not get cosmetic surgery, but I would not ban it – and will try not to think ill of those who choose it
So, how should we assess the ethics of new biomedical procedures when we know that society's views may change? More specifically, what should we think of He Jiankui's experiment with human babies?
First, look to see whether the procedure in question violates, at least fairly clearly, some rule in your ethical or moral code. If so, your choice may not be difficult. But if the procedure is unmentioned in your moral code, probably because it was inconceivable to the code's creators, examine the consequences of the act.
If the procedure is just novel, and not something that touches on important moral concerns, looking at the likely consequences may be enough for your ethical analysis –though it is always worth remembering that predicting consequences perfectly is impossible and predicting them well is never certain. If it does touch on morally significant issues, you need to think those issues through. The consequences may be important to your conclusions but they may not be determinative.
And, then, if you conclude that it is not ethical from your perspective, you need to take yet another step and consider whether it should be banned for people who do not share your perspective. Sometimes the answer will be yes – that psychopaths may not view murder as immoral does not mean we have to let them kill – but sometimes it will be no.
What does this say about He Jiankui's experiment? I have no qualms in condemning it, unequivocally. The potential risks to the babies grossly outweighed any benefits to them, and to science. And his secret work, against a near universal scientific consensus, privileged his own ethical conclusions without giving anyone else a vote, or even a voice.
But if, in ten or twenty years, genome editing of human embryos is shown to be safe (enough) and it is proposed to be used for good reasons – say, to relieve human suffering that could not be treated in other good ways – and with good consents from those directly involved as well as from the relevant society and government – my answer might well change. Yours may not. Bioethics is a process for approaching questions; it is not a set of universal answers.
This article opened with a quotation from the 1848 Communist Manifesto, referring to the dizzying pace of change from industrialization and modernity. You don't need to be a Marxist to appreciate that sentiment. Change – especially in the biosciences – keeps accelerating. How should we assess the ethics of new biotechnologies? The best we can, with what we know, at the time we inhabit. And, in the face of vast uncertainty, with humility.
This Brain Doc Has a “Repulsive” Idea to Make Football Safer
What do football superstars Tom Brady, Drew Brees, Philip Rivers, and Adrian Peterson all have in common? Last year they wore helmets that provided the poorest protection against concussions in all the NFL.
"You're only as protected as well as the worst helmet that's out there."
A Dangerous Policy
Football helmets are rated on a one-star to five-star system based on how well they do the job of protecting the player. The league has allowed players to use their favorites, regardless of the star rating.
The Oxford-trained neuroscientist Ray Colello conducted a serious analysis of just how much the protection can vary between each level of star rating. Colello and his team of graduate students sifted through two seasons of game video to identify which players were wearing what helmets. There was "a really good correlation with position, but the correlation is much more significant based on age."
"The average player in the NFL is 26.6 years old, but the average age of a player wearing a one-star helmet is 34. And for anyone who knows football, that's ancient," the brain doc says. "Then for our two-star helmet, it's 32; and for a three-star helmet it's 29." Players were sticking with the helmets they were familiar with in college, despite the fact that equipment had improved considerably in recent years.
"You're only as protected as well as the worst helmet that's out there," Colello explains. Offering an auto analogy, he says, "It's like, if you run into the back of a Pinto, even if you are in a five-star Mercedes, that gas tank may still explode and you are still going to die."
It's one thing for a player to take a risk at scrambling his own brain; it's another matter to put a teammate or opponent at needless risk. Colello published his analysis early last year and the NFL moved quickly to ban the worst performing helmets, starting next season.
Some of the 14 players using the soon-to-be-banned helmets, like Drew Brees and Philip Rivers, made the switch to a five-star helmet at the start of training camp and stayed with it. Adrian Peterson wore a one-star helmet throughout the season.
Tom Brady tried but just couldn't get comfortable with a new bonnet and, after losing a few games, switched back to his old one in the middle of the season; he says he's going to ask the league to "grandfather in" his old helmet so he can continue to use it.
As for Colello, he's only just getting started. The brain doc has a much bigger vision for the future of football safety. He wants to prevent concussions from even occurring in the first place by creating an innovative new helmet that's unlike anything the league has ever seen.
Oxford-trained neuroscientist Ray Colello is on a mission to make football safer.
(Photo credit: VCU public affairs)
"A Force Field" of Protection
His inspiration was serendipitous; he was at home watching a football game on TV when Denver Bronco's receiver Wes Welker was hit, lay flat on the field with a concussion, and was carted off. As a commercial flickered on the screen, he ambled into the kitchen for another beer. "What those guys need is a force field protecting them," he thought to himself.
Like so many households, the refrigerator door was festooned with magnets holding his kids' school work in place. And in that eureka moment the idea popped into his head: "Maybe the repulsive force of magnets can put a break on an impact before it even occurs." Colello has spent the last few years trying to turn his concept into reality.
Newton's laws of physics – mass and speed – play out graphically in a concussion. The sudden stop of a helmet-to-helmet collision can shake the brain back and forth inside the skull like beans in a maraca. Dried beans stand up to the impact, making their distinctive musical sound; living brain tissue is much softer and not nearly so percussive. The resulting damage is a concussion.
The risk of that occurring is greater than you might think. Researchers using accelerometers inside helmets have determined that a typical college football player experiences about 600 helmet-to-helmet contacts during a season of practice and games. Each hit generates a split second peak g-force of 20 to 150 within the helmet and the odds of one causing a concussion increase sharply over 100 gs of force.
By comparison, astronauts typically experience a maximum sustained 3gs during lift off and most humans will black out around 9gs, which is why fighter pilots wear special pressure suits to counter the effects.
"It stretches the time line of impact quite dramatically. In fact in most instances, it doesn't even hit."
The NFL's fastest player, Chris Johnson, can run 19.3 mph. A collision at that speed "produces 120gs worth of force," Colello explains. "But if you can extend that time of impact by just 5 milliseconds (from 12 to 17msec) you'll shift that g-force down to 84. There is a very good chance that he won't suffer a concussion."
The neuroscientist dived into learning all he could about the physics magnets. It turns out that the most powerful commercially available magnet is an alloy made of neodymium, iron, and boron. The elements can be mixed and glued together in any shape and then an electric current is run through to make it magnetic; the direction of the current establishes the north-south poles.
A 1-pound neodymium magnet can repulse 600 times its own weight, even though the magnetic field extends less than an inch. That means it can push back a magnet inside another helmet but not affect the brain.
Crash Testing the Magnets
Colello couldn't wait to see if his idea panned out. With blessing from his wife to use their credit card, he purchased some neodymium magnets and jury-rigged experiments at home.
The reinforced plastics used in football helmets don't affect the magnetic field. And the small magnets stopped weights on gym equipment that were dropped from various heights. "It stretches the time line of impact quite dramatically. In fact in most instances, it doesn't even hit," says Colello. "We are dramatically shifting the curve" of impact.
Virginia Commonwealth University stepped in with a $50,000 innovation grant to support the next research steps. The professor ordered magnets custom-designed to fit the curvature of space inside the front and sides of existing football helmets. That makes it impossible to install them the wrong way, and ensures the magnets' poles will always repel and not attract. It adds about a pound and a half to the weight of the helmet.
a) The brain in a helmet. b) Placing the magnet. c) Measuring the impact of a helmet-to-helmet collision. d) How magnets reduce the force of impact.
(Courtesy Ray Colello)
Colello rented crash test dummy heads crammed with accelerometers and found that the magnets performed equally well at slowing collisions when fixed to a pendulum in a test that approximated a helmet and head hitting a similarly equipped helmet. It impressively reduced the force of contact.
The NFL was looking for outside-the-box thinking to prevent concussions. It was intrigued by Colello's approach and two years ago invited him to submit materials for review. To be fair to all entrants, the league proposed to subject all entries to the same standard crush test to see how well each performed in lessening impact. The only trouble was, Colello's approach was designed to avoid collisions, not lessen their impact. The test wouldn't have been a valid evaluation and he withdrew from consideration.
But Colello's work caught the attention of Stefan Duma, an engineering professor at Virginia Tech who developed the five-star rating system for football helmets.
"In theory it makes sense to use [the magnets] to slow down or reduce acceleration, that's logical," says Duma. He believes current helmet technology is nearing "the end of the physics barrier; you can only absorb so much energy in so much space," so the field is ripe for new approaches to improve helmet technology.
However, one of Duma's concerns is whether magnets "are feasible from a weight standpoint." Most helmets today weigh between two and four pounds, and a sufficiently powerful magnet might add too much weight. One possibility is using an electromagnet, which potentially could be lighter and more powerful, particularly if the power supply could be carried lower in the body, say in the shoulder pads.
Colello says his lab tests are promising enough that the concept needs to be tried out on the playing field. "We need to make enough helmets for two teams to play each other in a regulation-style game and measure the impact forces that are generated on each, and see if there is a significant reduction." He is waiting to hear from the National Institutes of Health on a grant proposal to take that next step toward dramatically reducing the risk of concussions in the NFL.
Just five milliseconds could do it.