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.
You read an online article about climate change, then start scanning the comments on Facebook. Right on cue, Seth the Science Denier chimes in with:
The study found that science deniers whose arguments go unchallenged can harm other people's attitudes toward science.
"Humans didn't cause this. Climate is always changing. The earth has always had cycles of warming and cooling—what's happening now isn't new. The idea that humans are causing something that happened long before humans were even around is absurd."
You know he's wrong. You recognize the fallacy in his argument. Do you take the time to engage with him, or write him off and move along?
New research suggests that countering science deniers like Seth is important—not necessarily to change their minds, but to keep them from influencing others.
Looking at Seth's argument, someone without much of a science background might think it makes sense. After all, climate is always changing. The earth has always gone through cycles, even before humans. Without a scientifically sound response, a reader may begin to doubt that human-caused climate change is really a thing.
A study published in Nature found that science deniers whose arguments go unchallenged can harm other people's attitudes toward science. Many people read discussions without actively engaging themselves, and some may not recognize erroneous information when they see it. Without someone to point out how a denier's statements are false or misleading, people are more likely to be influenced by the denier's arguments.
Researchers tested two strategies for countering science denial—by topic (presenting the facts) and by technique (addressing the illogical argument). Rebutting a science denier with facts and pointing out the fallacies in their arguments both had a positive effect on audience attitudes toward legitimate science. A combination of topic and technique rebuttals also had a positive effect.
"In the light of these findings we recommend that advocates for science train in topic and technique rebuttal," the authors wrote. "Both strategies were equally effective in mitigating the influence of science deniers in public debates. Advocates can choose which strategy they prefer, depending on their levels of expertise and confidence."
Who you're really addressing are the lurkers who might be swayed by misinformation if it isn't countered by real science.
So what does that look like? If we were to counter Seth's statements with a topic rebuttal, focusing on facts, it might look something like this:
Yes, climate has always changed due to varying CO2 levels in the atmosphere. Scientists have tracked that data. But they also have data showing that human activity, such as burning fossil fuels, has dramatically increased CO2 levels. Climate change is now happening at a rate that isn't natural and is dangerous for life as we know it.
A technique rebuttal might focus on how Seth is using selective information and leaving out important facts:
Climate has always changed, that's true. But you've omitted important information about why it changes and what's different about the changes we're seeing now.
Ultimately, we could combine the two techniques in something like this:
Climate has always changed, but you've omitted important information about why it changes and what's different about what we're seeing now. Levels of CO2 in the atmosphere are largely what drives natural climate change, but human activity has increased CO2 beyond natural levels. That's making climate change happen faster than it should, with devastating effects for life on Earth.
Remember that the point is not to convince Seth, though it's great if that happens. Who you're really addressing are the lurkers who might be swayed by misinformation if it isn't countered by truth.
It's a wacky world out there, science lovers. Keep on fighting the good fight.
Diagnosed by App: Medical Testing in the Palm of Your Hand
Urinary tract infections aren't life-threatening, but they can be excruciatingly painful and debilitating.
"Overnight, I'd be gripped by this searing pain and I can barely walk," says Ling Koh, a Los Angeles-based bioengineer. But short of going to the ER or urgent care, she'd have to suffer for a few days until she could get in to see her family doctor for an antibiotic prescription.
Smartphones are now able to do on-the-spot diagnostic tests that were previously only able to be performed in a lab.
No longer. Koh, who works for Scanwell Health, was instrumental in the development of the company's smartphone app that is FDA-cleared for urinary tract infection screening. It allows someone to test urine at home using a paper test strip — the same one used by doctors in ERs and labs. The phone app reads a scan card from the test kit that can analyze what's on the strip and then connect the patient to a physician who can make a virtual diagnosis.
Test strips cost $15 for a three-pack and consultation with a doc is about the same as an average co-pay -- $25, and the app matches the quality of clinical laboratory tests, according to the company. Right now, you can get a referral to a telehealth visit with a doctor in California and get a prescription. A national rollout is in the works within the next couple of months.
"It's so easy to use them at home and eliminate the inefficiencies in the process," says Koh. "A telemedicine doctor can look at the test results and prescribe directly to the pharmacy instead of women waiting at home, miserable, and crying in the bathtub."
Scanwell is now involved in an ongoing National Institutes of Health- sponsored study of chronic kidney disease to test a version of the app to identify patients who have the disease, which affects more than 30 million Americans. "Because kidney disease has virtually no symptoms, by the time people realize they're sick, their illness is advanced and they're ready for dialysis," says Koh. "If we can catch it sooner, early intervention can help them avoid kidney failure."
Smartphones have changed society — and now they may change medical care, too. Thanks to the incredible processing capabilities of our smartphones, which come equipped with a camera, access to the internet and are thousands of times faster than the 1960s era NASA computers that ran the Apollo Moon Mission, these pocket-sized powerhouses have become an invaluable tool for managing our health and are even able to do on-the-spot diagnostic tests that were previously only able to be performed in a lab.
This shift to in-home testing is the wave of the future, promising to ease some of the medical care bottlenecks in which patients can have two- to three-week waits to see their family doctors and lift some of the burdens on overworked physicians.
"This is really the democratization of medicine because a lot of the things we used to rely on doctors, hospitals, or labs to do we'll be able to do ourselves," says Dr. Eric Topol, an eminent cardiologist and digital health pioneer at the Scripps Clinic and Research Institute in La Jolla.
But troubling questions remain. Aside from the obvious convenience, are these tests truly as accurate as ones in a doctor's office? And with all this medical information stored and collected by smartphones, will privacy be sacrificed? Will friends, family members, and employers suddenly have access to personal medical information we'd rather keep to ourselves?
The range of what these DIY health care apps can do is mind-boggling, and even more complex tests are on the way.
"I'm really worried about that because we've let our guard down," says Topol. "Data stored on servers is a target for cyber thieves — and data is being breached, hacked, brokered, and sold, and we're complacent."
Still, the apps have come a long way since 2011 when Topol whipped out an experimental smartphone electro-cardiogram that he had been testing on his patients when a fellow passenger on a flight from Washington D.C. was seized with severe chest pains. At 35,000 feet in the air, the app, which uses fingertip sensors to detect heart rate, showed the man was having a heart attack. After an emergency landing, the passenger was rushed to the closest hospital and survived. These days, even the Apple Watch has an FDA-approved app that can monitor your electro-cardiogram readings.
The range of what these DIY health care apps can do is mind-boggling, and even more complex tests are on the way. Phone apps can now monitor sleep quality to detect sleep apnea, blood pressure, weight and temperature. In the future, rapid diagnostic tests for infectious diseases, like flu, Dengue or Zika, and urinalysis will become common.
"There is virtually no limit to the kinds of testing that can be done using a smartphone," says Dr. John Halamka, Executive Director of the Health Technology Exploration Center at Beth Israel Lahey Health. "No one wants to drive to a clinician's office or lab if that same quality testing can be achieved at a lower cost without leaving home."
SkinVision's skin cancer screening tool, for instance, can tell if a suspicious mole is cancerous. Users take three photos, which are then run through the app's algorithm that compares their lesions with more than three million pictures, evaluating such elements as asymmetry, color, and shape, and spits out an assessment within thirty seconds. A team of in-house experts provide a review regardless of whether the mole is high or low risk, and the app encourages users to see their doctors. The Dutch-based company's app has been used by more than a million people globally in the EU, and in New Zealand and Australia, where skin cancer is rampant and early detection can save lives. The company has plans to enter the U.S. market, according to a spokesperson.
Apps like Instant Heart Rate analyze blood flow, which can indicate whether your heart is functioning normally, while uChek examines urine samples for up to 10 markers for conditions like diabetes and urinary tract infections. Some behavioral apps even have sensors that can spot suicide risks if users are less active, indicating they may be suffering from a bout of the blues.
Even more complex tests are in the research pipeline. Apps like ResAppDX could eventually replace x-rays, CT scans, and blood tests in diagnosing severe respiratory infections in kids, while an EU-funded project called i-Prognosis can track a variety of clues — voice changes, facial expressions, hand steadiness — that indicate the onset of Parkinson's disease.
These hand-held testing devices can be especially helpful in developing countries, and there are pilot programs to use smartphone technology to diagnose malaria and HIV infections in remote outposts in Africa.
"In a lot of these places, there's no infrastructure but everyone has a smartphone," says Scanwell's Koh. "We need to leverage the smartphone in a clinically relevant way."
However, patient privacy is an ongoing concern. A 2019 review in the Journal of the American Medical Association conducted by Australian and American researchers looked at three dozen behavioral health apps, mainly for depression and smoking cessation. They found that about 70 percent shared data with third parties, like Facebook and Google, but only one third of them disclosed this in a privacy policy.
"Patients just blindly accept the end user agreements without understanding the implications."
Users need to be vigilant, too. "Patients just blindly accept the end user agreements without understanding the implications," says Hamalka, who is also the Chief Information Officer and Dean for Technology at Harvard Medical School.
And quality control is an issue. Right now, the diagnostic tools currently available have been vetted by the FDA, and overseas companies like Skin Vision have been scrutinized by the U.K.'s National Health Service and the EU. But the danger is that a lot of apps are going to be popping up soon that haven't been properly tested, due to loopholes in the regulations.
"All we want," says Topol, "are rigorous studies to make sure what consumers are using is validated."
[Correction, August 19th, 2019: An earlier version of this story misstated the specifics of SkinVision's service. A team of in-house experts reviews users' submissions, not in-house dermatologists, and the service is not free.]