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.
Can Genetic Testing Help Shed Light on the Autism Epidemic?
Autism cases are still on the rise, and scientists don't know why. In April, the Centers for Disease Control (CDC) reported that rates of autism had increased once again, now at an estimated 1 in 59 children up from 1 in 68 just two years ago. Rates have been climbing steadily since 2007 when the CDC initially estimated that 1 in 150 children were on the autism spectrum.
Some clinicians are concerned that the creeping expansion of autism is causing the diagnosis to lose its meaning.
The standard explanation for this increase has been the expansion of the definition of autism to include milder forms like Asperger's, as well as a heightened awareness of the condition that has improved screening efforts. For example, the most recent jump is attributed to children in minority communities being diagnosed who might have previously gone under the radar. In addition, more federally funded resources are available to children with autism than other types of developmental disorders, which may prompt families or physicians to push harder for a diagnosis.
Some clinicians are concerned that the creeping expansion of autism is causing the diagnosis to lose its meaning. William Graf, a pediatric neurologist at Connecticut Children's Medical Center, says that when a nurse tells him that a new patient has a history of autism, the term is no longer a useful description. "Even though I know this topic extremely well, I cannot picture the child anymore," he says. "Use the words mild, moderate, or severe. Just give me a couple more clues, because when you say autism today, I have no idea what people are talking about anymore."
Genetic testing has emerged as one potential way to remedy the overly broad label by narrowing down a heterogeneous diagnosis to a specific genetic disorder. According to Suma Shankar, a medical geneticist at the University of California, Davis, up to 60 percent of autism cases could be attributed to underlying genetic causes. Common examples include Fragile X Syndrome or Rett Syndrome—neurodevelopmental disorders that are caused by mutations in individual genes and are behaviorally classified as autism.
With more than 500 different mutations associated with autism, very few additional diagnoses provide meaningful information.
Having a genetic diagnosis in addition to an autism diagnosis can help families in several ways, says Shankar. Knowing the genetic origin can alert families to other potential health problems that are linked to the mutation, such as heart defects or problems with the immune system. It may also help clinicians provide more targeted behavioral therapies and could one day lead to the development of drug treatments for underlying neurochemical abnormalities. "It will pave the way to begin to tease out treatments," Shankar says.
When a doctor diagnoses a child as having a specific genetic condition, the label of autism is still kept because it is more well-known and gives the child access to more state-funded resources. Children can thus be diagnosed with multiple conditions: autism spectrum disorder and their specific gene mutation. However, with more than 500 different mutations associated with autism, very few additional diagnoses provide meaningful information. What's more, the presence or absence of a mutation doesn't necessarily indicate whether the child is on the mild or severe end of the autism spectrum.
Because of this, Graf doubts that genetic classifications are really that useful. He tells the story of a boy with epilepsy and severe intellectual disabilities who was diagnosed with autism as a young child. Years later, Graf ordered genetic testing for the boy and discovered that he had a mutation in the gene SYNGAP1. However, this knowledge didn't change the boy's autism status. "That diagnosis [SYNGAP1] turns out to be very specific for him, but it will never be a household name. Biologically it's good to know, and now it's all over his chart. But on a societal level he still needs this catch-all label [of autism]," Graf says.
"It gives some information, but to what degree does that change treatment or prognosis?"
Jennifer Singh, a sociologist at Georgia Tech who wrote the book Multiple Autisms: Spectrums of Advocacy and Genomic Science, agrees. "I don't know that the knowledge gained from just having a gene that's linked to autism," is that beneficial, she says. "It gives some information, but to what degree does that change treatment or prognosis? Because at the end of the day you have to address the issues that are at hand, whatever they might be."
As more children are diagnosed with autism, knowledge of the underlying genetic mutation causing the condition could help families better understand the diagnosis and anticipate their child's developmental trajectory. However, for the vast majority, an additional label provides little clarity or consolation.
Instead of spending money on genetic screens, Singh thinks the resources would be better used on additional services for people who don't have access to behavioral, speech, or occupational therapy. "Things that are really going to matter for this child in their future," she says.
This past March, headlines suddenly flooded the Internet about a startup company called Nectome. Founded by two graduates of the Massachusetts Institute of Technology, the new company was charging people $10,000 to join a waiting list to have their brains embalmed, down to the last neuron, using an award-winning chemical compound.
While the lay public presumably burnt their wills and grew ever more excited about the end of humanity's quest for immortality, neurologists let out a collective sigh.
Essentially, participants' brains would turn to a substance like glass and remain in a state of near-perfect preservation indefinitely. "If memories can truly be preserved by a sufficiently good brain banking technique," Nectome's website explains, "we believe that within the century it could become feasible to digitize your preserved brain and use that information to recreate your mind." But as with most Faustian bargains, Nectome's proposition came with a serious caveat -- death.
That's right, in order for Nectome's process to properly preserve your connectome, the comprehensive map of the brain's neural connections, you must be alive (and under anesthesia) while the fluid is injected. This way, the company postulates, when the science advances enough to read and extract your memories someday, your vitrified brain will still contain your perfectly preserved essence--which can then be digitally recreated as a computer simulation.
Almost immediately this story gained buzz with punchy headlines: "Startup wants to upload your brain to the cloud, but has to kill you to do it," "San Junipero is real: Nectome wants to upload your brain," and "New tech firm promises eternal life, but you have to die."
While the lay public presumably burnt their wills and grew ever more excited about the end of humanity's quest for immortality, neurologists let out a collective sigh -- hype had struck the scientific community once again.
The truth about Nectome is that its claims are highly speculative and no hard science exists to suggest that our connectome is the key to our 'being,' nor that it can ever be digitally revived. "We haven't come even close to understanding even the most basic types of functioning in the brain," says neuroscientist Alex Fox, who was educated at the University of Queensland in Australia. "Memory storage in the brain is only a theoretical concept [and] there are some seriously huge gaps in our knowledge base that stand in the way of testing [the connectome] theory."
After the Nectome story broke, Harvard computational neuroscientist Sam Gershman tweeted out:
"Didn't anyone tell them that we've known the C Elegans (a microscopic worm) connectome for over a decade but haven't figured out how to reconstruct all of their memories? And that's only 7000 synapses compared to the trillions of synapses in the human brain!"
Hype can come from researchers themselves, who are under an enormous amount of pressure to publish original work and maintain funding.
How media coverage of Nectome went from an initial fastidiously researched article in the MIT Technology Review by veteran science journalist Antonio Regalado to the click-bait frenzy it became is a prime example of the 'science hype' phenomenon. According to Adam Auch, who holds a doctorate in philosophy from Dalhousie University in Nova Scotia, Canada, "Hype is a feature of all stages of the scientific dissemination process, from the initial circulation of preliminary findings within particular communities of scientists, to the process by which such findings come to be published in peer-reviewed journals, to the subsequent uptake these findings receive from the non-specialist press and the general public."
In the case of Nectome, hype was present from the word go. Riding the high of several major wins, including having raised over one million dollars in funding and partnering with well-known MIT neurologist Edward Boyden, Nectome founders Michael McCanna and Robert McIntyre launched their website on March 1, 2018. Just one month prior, they were able to purchase and preserve a newly deceased corpse in Portland, Oregon, showing that vitrifixation, their method of chemical preservation, could be used on a human specimen. It had previously won an award for preserving every synaptic structure on a rabbit brain.
The Nectome mission statement, found on its website, is laced with saccharine language that skirts the unproven nature of the procedure the company is peddling for big bucks: "Our mission is to preserve your brain well enough to keep all its memories intact: from that great chapter of your favorite book to the feeling of cold winter air, baking an apple pie, or having dinner with your friends and family."
This rhetoric is an example of hype that can come from researchers themselves, who are under an enormous amount of pressure to publish original work and maintain funding. As a result, there is a constant push to present science as "groundbreaking" when really, as is apparently the case with Nectome, it is only a small piece in a much larger effort.
Calling out the audacity of Nectome's posited future, neuroscientist Gershman commented to another publication, "The important question is whether the connectome is sufficient for memory: Can I reconstruct all memories knowing only the connections between neurons? The answer is almost certainly no, given our knowledge about how memories are stored (itself a controversial topic)."
The former home page of Nectome's website, which has now been replaced by a statement titled, "Response to recent press."
Furthermore, universities like MIT, who entered into a subcontract with Nectome, are under pressure to seek funding through partnerships with industry as a result of the Bayh-Dole Act of 1980. Also known as the Patent and Trademark Law Amendments Act, this piece of legislation allows universities to commercialize inventions developed under federally funded research programs, like Nectome's method of preserving brains, formally called Aldehyde-Stabilized Cryopreservation.
"[Universities use] every incentive now to talk about innovation," explains Dr. Ivan Oransky, president of the Association of Health Care Journalists and co-founder of retractionwatch.com, a blog that catalogues errors and fraud in published research. "Innovation to me is often a fancy word for hype. The role of journalists should not be to glorify what universities [say, but to] tell the closest version of the truth they can."
In this case, a combination of the hyperbolic press, combined with some impressively researched expose pieces, led MIT to cut its ties with Nectome on April 2nd, 2018, just two weeks after the news of their company broke.
The solution to the dangers of hype, experts say, is a more scientifically literate public—and less clickbait-driven journalism.
Because of its multi-layered nature, science hype carries several disturbing consequences. For one, exaggerated coverage of a discovery could mislead the public by giving them false hope or unfounded worry. And media hype can contribute to a general mistrust of science. In these instances, people might, as Auch puts it, "fall back on previously held beliefs, evocative narratives, or comforting biases instead of well-justified scientific evidence."
All of this is especially dangerous in today's 'fake news' era, when companies or political parties sow public confusion for their own benefit, such as with global warming. In the case of Nectome, the danger is that people might opt to end their lives based off a lacking scientific theory. In fact, the company is hoping to enlist terminal patients in California, where doctor-assisted suicide is legal. And 25 people have paid the $10,000 to join Nectome's waiting list, including Sam Altman, president of the famed startup accelerator Y Combinator. Nectome now has offered to refund the money.
Founders McCanna and McIntyre did not return repeated requests for comment for this article. A new statement on their website begins: "Vitrifixation today is a powerful research tool, but needs more research and development before anyone considers applying it in a context other than research."
The solution to the dangers of hype, experts say, is a more scientifically literate public—and less clickbait-driven journalism. Until then, it seems that companies like Nectome will continue to enjoy at least 15 minutes of fame.