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.
Announcing Our First Short Story Contest (With Prizes!)
Leapsmag is all about high-quality journalism and expert commentary. So you may be wondering, why are we hosting a fiction contest?
The answer is that some of the most visionary ideas for the future of humanity and technology first emerged in fiction, from Jules Verne's prescient novels about space, air, and underwater travels in the 19th century, to Arthur C. Clarke's prediction of satellite communications in 1945, to Isaac Asimov's exploration of robot ethics in the 1950s, to William Gibson's depiction of "cyberspace" in 1982.
But speculative fiction writers don't only anticipate big breakthroughs; they also care about probing the societal, personal, and moral impacts of new technology.
Will the next astute observation come in the form of a short story for leapsmag? Let's find out!
ABOUT THE CONTEST:
The Prompt:
Explore a big moral question or a new opportunity raised by an emerging technology today, in the form of an original, previously unpublished piece of fiction of up to 3000 words.
The Rules:
Submissions must be received by midnight EST on September 15th, 2018. Send your story as a double-spaced attachment in size 12 Times New Roman font to kira@leapsmag.com. Include your name and a short bio. It is free to enter, and authors retain all ownership of their work. Upon submitting an entry, the author agrees to grant leapsmag one-time nonexclusive publication rights.
All submissions will be judged by the Editor-in-Chief on the basis of insightfulness, originality, quality of storytelling, and relevance to the prompt. The Contest is open to anyone around the world of any age, except for the friends and family of leapsmag staff and associates.
The winners will be announced by October 15th, 2018.
The Prizes:
Grand Prize: $500, publication of your story on leapsmag, and promotion on our social media channels.
First Runner-Up: $100 and a shout-out on our social media channels.
Good luck!
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.
Where would you turn if you wanted the best advice about trying a new drug? A doctor with years of specialized training? A website with opinions from leading experts in the field? Maybe a review article by a trustworthy medical reporter. Or, maybe even go right to the source — an article about the drug in the peer-reviewed medical literature.
Or you could choose to get advice from someone whose education ended with high school and who almost certainly has had no training in pharmacology or scientific methodology. In America the answer is, sadly, the high school graduate if he or she is a huge celebrity.
Kardashian appears to have blessed a drug she never used and had no basis to endorse.
Drug manufacturers know this. They turn to celebrities, no matter how ignorant, ill-informed, money grubbing or air-headed, to pitch their goods directly to you on TV and the internet.
The latest example of this reliance on the utterly unqualified is the use of the surgically reengineered, reality show TV star Kim Kardashian to endorse a pill for women suffering from morning sickness during pregnancy. Kim, whose science training, whatever it was, ended when she graduated California's Marymount high school, recently offered this assessment of the medication:
"You know how sick I was while pregnant; I could barely get out of bed. That was before I found a safe & effective med to treat my morning sickness when diet & lifestyle changes didn't help. I hear there's a new formulation of the drug combination I took that's made to work faster & longer. If you're pregnant & feeling sick & changing your diet & lifestyle doesn't work, ask your doctor about Bonjesta® (doxylamine succinate/pyridoxine HCl). Most common side effect is drowsiness. Bonjesta.com for info."
She appears to have blessed a drug she never used and had no basis to endorse. And whether she got all the possible important side effects out there is not clear. In 2015, her internet post lauding another morning sickness drug, Diclegis, made by the same company, Duchesnay, now pushing Bonjesta, earned her $500,000 and Duchesnay a warning letter from the FDA for false and misleading advertising. Duchesnay dealt with the FDA and went on its merry way coming up with new meds relying on confirmation of their value by Kim.
Artificial demand creates more expense downstream for insurers, payer programs, and patients.
It seems pretty likely she was handsomely paid for her kind words about Bonjesta--payment that, if it occurred, is not disclosed in her endorsement or in most commercials in which celebrities tout drugs, vaccines and devices.
Legislators and patients often wonder why the cost of drugs in America is so high relative to the rest of the world. Well, one reason is the rest of the world does not tolerate direct-to-consumer ads aimed at ginning up demand when touted by actors, soap opera stars, sports stars, reality tv icons, quiz show hosts and others selling their fame so you will use a company's drug. Increasing the demand through celebrity endorsement allows companies to jack up their prices. Duchesnay did just that! Artificial demand creates more expense downstream for insurers, payer programs, and patients.
We treat marketing drugs on a par with marketing cosmetics, dishwashers, and fast food. And we get what Kim and other media celebs are paid for: useless information from unqualified sources who can grab eyeballs and get you to pester your doctor about what your idols say works.