New drug for schizophrenia could meet desperate need for better treatments
The field of treating schizophrenia with drugs has been stuck in a long drought but, this month, a late-stage clinical trial found a new drug called KarXT could treat a range of symptoms.
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.
“Young Blood” Transfusions Are Not Ready For Primetime – Yet
A young woman donates blood.
The world of dementia research erupted into cheers when news of the first real victory in a clinical trial against Alzheimer's Disease in over a decade was revealed last October.
By connecting the circulatory systems of a young and an old mouse, the regenerative potential of the young mouse decreased, and the old mouse became healthier.
Alzheimer's treatments have been famously difficult to develop; 99 percent of the 200-plus such clinical trials since 2000 have utterly failed. Even the few slight successes have failed to produce what is called 'disease modifying' agents that really help people with the disease. This makes the success, by the midsize Spanish pharma company Grifols, worthy of special attention.
However, the specifics of the Grifols treatment, a process called plasmapheresis, are atypical for another reason - they did not give patients a small molecule or an elaborate gene therapy, but rather simply the most common component of normal human blood plasma, a protein called albumin. A large portion of the patients' normal plasma was removed, and then a sterile solution of albumin was infused back into them to keep their overall blood volume relatively constant.
So why does replacing Alzheimer's patients' plasma with albumin seem to help their brains? One theory is that the action is direct. Alzheimer's patients have low levels of serum albumin, which is needed to clear out the plaques of amyloid that slowly build up in the brain. Supplementing those patients with extra albumin boosts their ability to clear the plaques and improves brain health. However, there is also evidence suggesting that the problem may be something present in the plasma of the sick person and pulling their plasma out and replacing it with a filler, like an albumin solution, may be what creates the purported benefit.
This scientific question is the tip of an iceberg that goes far beyond Alzheimer's Disease and albumin, to a debate that has been waged on the pages of scientific journals about the secrets of using young, healthy blood to extend youth and health.
This debate started long before the Grifols data was released, in 2014 when a group of researchers at Stanford found that by connecting the circulatory systems of a young and an old mouse, the regenerative potential of the young mouse decreased, and the old mouse became healthier. There was something either present in young blood that allowed tissues to regenerate, or something present in old blood that prevented regeneration. Whatever the biological reason, the effects in the experiment were extraordinary, providing a startling boost in health in the older mouse.
After the initial findings, multiple research groups got to work trying to identify the "active factor" of regeneration (or the inhibitor of that regeneration). They soon uncovered a variety of compounds such as insulin-like growth factor 1 (IGF1), CCL11, and GDF11, but none seemed to provide all the answers researchers were hoping for, with a number of high-profile retractions based on unsound experimental practices, or inconclusive data.
Years of research later, the simplest conclusion is that the story of plasma regeneration is not simple - there isn't a switch in our blood we can flip to turn back our biological clocks. That said, these hypotheses are far from dead, and many researchers continue to explore the possibility of using the rejuvenating ability of youthful plasma to treat a variety of diseases of aging.
But the bold claims of improved vigor thanks to young blood are so far unsupported by clinical evidence.
The data remain intriguing because of the astounding results from the conjoined circulatory system experiments. The current surge in interest in studying the biology of aging is likely to produce a new crop of interesting results in the next few years. Both CCL11 and GDF11 are being researched as potential drug targets by two startups, Alkahest and Elevian, respectively.
Without clarity on a single active factor driving rejuvenation, it's tempting to try a simpler approach: taking actual blood plasma provided by young people and infusing it into elderly subjects. This is what at least one startup company, Ambrosia, is now offering in five commercial clinics across the U.S. -- for $8,000 a liter.
By using whole plasma, the idea is to sidestep our ignorance, reaping the benefits of young plasma transfusion without knowing exactly what the active factors are that make the treatment work in mice. This space has attracted both established players in the plasmapheresis field – Alkahest and Grifols have teamed up to test fractions of whole plasma in Alzheimer's and Parkinson's – but also direct-to-consumer operations like Ambrosia that just want to offer patients access to treatments without regulatory oversight.
But the bold claims of improved vigor thanks to young blood are so far unsupported by clinical evidence. We simply haven't performed trials to test whether dosing a mostly healthy person with plasma can slow down aging, at least not yet. There is some evidence that plasma replacement works in mice, yes, but those experiments are all done in very different systems than what a human receiving young plasma might experience. To date, I have not seen any plasma transfusion clinic doing young blood plasmapheresis propose a clinical trial that is anything more than a shallow advertisement for their procedures.
The efforts I have seen to perform prophylactic plasmapheresis will fail to impact societal health. Without clearly defined endpoints and proper clinical trials, we won't know whether the procedure really lowers the risk of disease or helps with conditions of aging. So even if their hypothesis is correct, the lack of strong evidence to fall back on means that the procedure will never spread beyond the fringe groups willing to take the risk. If their hypothesis is wrong, then people are paying a huge amount of money for false hope, just as they do, sadly, at the phony stem cell clinics that started popping up all through the 2000s when stem cell hype was at its peak.
Until then, prophylactic plasma transfusions will be the domain of the optimistic and the gullible.
The real progress in the field will be made slowly, using carefully defined products either directly isolated from blood or targeting a bloodborne factor, just as the serious pharma and biotech players are doing already.
The field will progress in stages, first creating and carefully testing treatments for well-defined diseases, and only then will it progress to large-scale clinical trials in relatively healthy people to look for the prevention of disease. Most of us will choose to wait for this second stage of trials before undergoing any new treatments. Until then, prophylactic plasma transfusions will be the domain of the optimistic and the gullible.
Who’s Responsible for Curbing the Teen Vaping Epidemic?
A teenage girl vaping in a park.
E-cigarettes are big business. In 2017, American consumers bought more than $250 million in vapes and juice-filled pods, and spent $1 billion in 2018. By 2023, the global market could be worth $44 billion a year.
"My nine-year-old actually knows what Juuling is. In many cases the [school] bathroom is now referred to as 'the Juuling room.'"
Investors are trying to capitalize on the phenomenal growth. In July 2018, Juul Labs, the company that owns 70 percent of the U.S. e-cigarette market share, raised $1.25 billion at a $16 billion valuation, then sold a 35 percent stake to Phillip Morris USA owner Altria Group in December. The second transaction valued the company at $38 billion. While the traditional tobacco market remains much larger, it's projected to grow at less than two percent a year, making the attractiveness of the rapidly expanding e-cigarette market obvious.
While Juul and other e-cigarette manufacturers argue that their products help adults quit smoking – and there's some research to back this narrative up – much of the growth has been driven by children and teenagers. One CDC study showed a 48 percent rise in e-cigarette use by middle schoolers and a 78 percent increase by high schoolers between 2017 and 2018, a jump from 1.5 million kids to 3.6 million. In response to the study, F.D.A. Commissioner Scott Gottlieb said, "We see clear signs that youth use of electronic cigarettes has reached an epidemic proportion."
Another study found that teenagers between 15 and 17 were 16 times more likely to use Juul than people aged 25-34. In December, Surgeon General Jerome Adams said, "My nine-year-old actually knows what Juuling is. In many cases the [school] bathroom is now referred to as 'the Juuling room.'"
And the product is seriously addictive. A single Juul pod contains as much nicotine as a pack of 20 regular cigarettes. Considering that 90 percent of smokers are addicted by 18 years old, it's clear that steps need to be taken to combat the growing epidemic.
But who should take the lead? Juul and other e-cigarette companies? The F.D.A. and other government regulators? Schools? Parents?
The Surgeon General's website has a list of earnest possible texts that parents can send to their teens to dissuade them from Juuling, like: "Hope none of your friends use e-cigarettes around you. Even breathing the cloud they exhale can expose you to nicotine and chemicals that can be dangerous to your health." While parents can attempt to police their teens, many experts believe that the primary push should come at a federal level.
The regulation battle has already begun. In September, the F.D.A. announced that Juul had 60 days to show a plan that would prevent youth from getting their hands on the product. The result was for the company to announce that it wouldn't sell flavored pods in retail stores except for tobacco, menthol, and mint; Juul also shuttered its Instagram and Facebook accounts. These regulations mirrored an F.D.A. mandate two days later that required flavored e-cigarettes to be sold in closed-off areas. "This policy will make sure the fruity flavors are no longer accessible to kids in retail sites, plan and simple," Commissioner Gottlieb said when announcing the moves. "That's where they're getting access to the e-cigs and we intend to end those sales."
"There isn't a great history of the tobacco industry acting responsibly and being able to in any way police itself."
While so far, Gottlieb – who drew concerns about conflict of interest due to his past position as a board member at e-cigarette company, Kure – has pleased anti-smoking advocates with his efforts, some observers also argue that it needs to go further. "Overall, we didn't know what to expect when a new commissioner came in, but it's been quite refreshing how much attention has been paid to the tobacco industry by the F.D.A.," Robin Koval, CEO and president of Truth Initiative, said a day after the F.D.A. announced the proposed regulations. "It's important to have a start. I certainly want to give credit for that. But we were really hoping and feel that what was announced...doesn't go far enough."
The issue is the industry's inability or unwillingness to police itself in the past. Juul, however, claims that it's now proactively working to prevent young people from taking up its product. "Juul Labs and F.D.A. share a common goal – preventing youth from initiating on nicotine," a company representative said in an email. "To paraphrase Commissioner Gottlieb, we want to be the off-ramp for adult smokers to switch from cigarettes, not an on-ramp for America's youth to initiate on nicotine. We won't be successful in our mission to serve adult smokers if we don't narrow the on-ramp... Our intent was never to have youth use Juul products. But intent is not enough, the numbers are what matter, and the numbers tell us underage use of e-cigarette products is a problem. We must solve it."
Juul argues that its products help adults quit – even offering a calculator on the website showing how much people will save – and that it didn't target youth. But studies show otherwise. Furthermore, the youth smoking prevention curriculum the company released was poorly received. "It's what Philip Morris did years ago," said Bonnie Halpern-Felsher, a professor of pediatrics at Stanford who helped author a study on the program's faults. "They aren't talking about their named product. They are talking about vapes or e-cigarettes. Youth don't consider Juuls to be vapes or e-cigarettes. [Teens] don't talk about flavors. They don't talk about marketing. They did it to look good. But if you look at what [Juul] put together, it's a pretty awful curriculum that was put together pretty quickly."
The American Lung Association gave the FDA an "F" for failing to take mint and menthol e-cigs off the market, since those flavors remain popular with teens.
Add this all up, and in the end, it's hard to see the industry being able to police itself, critics say. Neither the past examples of other tobacco companies nor the present self-imposed regulations indicate that this will succeed.
"There isn't a great history of the tobacco industry acting responsibly and being able to in any way police itself," Koval said. "That job is best left to the F.D.A., and to the states and localities in what they can regulate and legislate to protect young people."
Halpern-Felsher agreed. "I think we need independent bodies. I really don't think that a voluntary ban or a regulation on the part of the industry is a good idea, nor do I think it will work," she said. "It's pretty much the same story, of repeating itself."
Just last week, the American Association of Pediatrics issued a new policy statement calling for the F.D.A. to immediately ban the sale of e-cigarettes to anyone under age 21 and to prohibit the online sale of vaping products and solutions, among other measures. And in its annual report, the American Lung Association gave the F.D.A. an "F" for failing to take mint and menthol e-cigs off the market, since those flavors remain popular with teens.
Few, if any people involved, want more regulation from the federal government. In an ideal world, this wouldn't be necessary. But many experts agree that it is. Anything else is just blowing smoke.