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.
Why Are Scientists and Patients Visiting This Island Paradise?
Dr. Conville Brown, a cardiologist-researcher in The Bahamas, is at the helm of a fascinating worldwide project: He's leading a movement to help accelerate innovation by providing scientists and patients from around the globe with a legal, cost-effective, and ethically rigorous place to conduct medical research, as well as to offer commercial therapies that are already approved in some jurisdictions, but not others. He recently spoke with Editor-In-Chief Kira Peikoff about The Bahamas' emerging ascendance in the scientific world. This interview has been edited and condensed for brevity.
"You don't want to take shortcuts from the perspective of not giving proper due diligence to the process, but you also don't want it to be overwhelmed with red tape."
Tell me about the work you do in the Bahamas – what is the research focus?
We have a couple research opportunities here. Several years ago, we established the Partners Clinical Research Centre, the idea being that we can partner with different people in different territories in the world, including the United States, and be able to perform ethical research as would be defined and adjudicated by an institutional review board and a properly constituted ethics committee. We do all of this with FDA rigor, but in a non-FDA jurisdiction.
By doing this, we want to look for the science behind the research, and want to know that there is a sound clinical hypothesis that's going to be tested. We also want to know that the safety of the human subjects is assured as much as possible, and of course, assess the efficacy of that which you're testing. We want to do this in the same manner as the FDA, except in a more accelerated and probably less bureaucratic manner. You don't want to take shortcuts from the perspective of not giving proper due diligence to the process, but you also don't want it to be overwhelmed with red tape, so that what could be 3 months takes 3 years. A jet ski turns around a lot faster than the Queen Mary.
Why do you think the clinical research process in other countries like the U.S. has become burdened with red tape?
The litigious nature of society is a contributing factor. If people are negligent, they deserve to be sued. Unfortunately, all too often, some things get taken too far, and sometimes, the pendulum swings too far in the wrong direction and then it's counterproductive, so the whole process then becomes so very heavily regulated and financially burdensome. A lot of American companies have gone outside the country to get their clinical trials and/or device testing done because it's too phenomenally expensive and time-consuming. We seek to make sure the same degree of diligence is exercised but in a lesser time frame, and of course, at a much lower cost.
The other aspect, of course, is that there are certain opportunities where we have major jurisdictions, as in Europe, that have determined that a therapy or device is safe. Those services and devices we can utilize in the Bahamas--not as a clinical research tool, but as a therapy, which of course, the United States is not able to do without FDA approval. That could easily take another five years. So there is an opportunity for us in that window to make available such therapies and devices to the North American community. I like to call this "Advanced Medical Tourism" or "Advanced TransNational Medical Care." Instead of somebody flying nine hours to Europe, they can also now fly to the Bahamas, as little as half an hour away, and as long as we are satisfied that the science is sound and the approvals are in place from a senior jurisdiction, then we can legally serve any patient that is eligible for that particular therapy.
Dr. Conville Brown
(Courtesy)
Are you seeing an influx of patients for that kind of medical tourism?
The numbers are increasing. The stem cell legislation has now been in place for two to three years, so we have a number of entities including some large international companies coming to the shores of the Bahamas to provide some therapies here, and others for research. The vast majority of our clientele are from abroad, particularly the U.S. We fully plan to increase the traffic flow to the Bahamas for medical tourism, or preferably, TransNational Medical Care, Advanced and Conventional.
How do patients find out about available therapies and trials happening there?
Advertising in the international arena for something that is perfectly legal within the confines of Bahamas is par for the course. But the marketing efforts have not been that heavy while all the processes and procedures are being fine-tuned and the various entities are set up to handle more than 100 people at a time.
"We were able to accelerate those programs, and do it a lot less expensively than can be done in continental countries, but just as well."
What kind of research is being done by companies who have come to the Bahamas?
We've been involved in first-in-man procedures for neuromodulation of the cardiovascular system, where we inserted a device into the blood vessels and stimulated the autonomic nervous system with a view to controlling patients' blood pressure and heart rate in conditions such as congestive heart failure. We have also looked at injectable glucose sensors, to continually monitor the blood glucose, and via a chip, can send the blood glucose measurement back to the patient's cell phone. So the patient looks at his phone for his blood sugar. That was phenomenally exciting, the clinical trial was very positive, and the company is now developing a final prototype to commercialize the product. We were able to accelerate those programs, and do it a lot less expensively than can be done in continental countries, but just as well. The Bahamas has also crafted legislation specifically for regenerative medicine and stem cell research, so that becomes an additional major attraction.
Do you ever find that there is skepticism around going to the Caribbean to do science?
When it comes to clinical research and new medical devices, one might be skeptical about the level of medical/scientific expertise that is resident here. We're here to show that we do in fact have that expertise resident within The Partners Clinical Research Centre, within The Partners Stem Cell Centre, and we have formed our partnerships accordingly so that when prudent and necessary, we bring in additional expertise from the very territories that are seeking to accelerate.
Have you seen a trend toward increasing interest from researchers around the world?
Absolutely. One company, for example, is interested not only in the clinical side, but also the preclinical side--where you can have animal lab experiments done in the Bahamas, and being able to bridge that more readily with the clinical side. That presents a major opportunity for parties involved because again, the financial savings are exponential without compromising standards.
"A person who is 75 and frail, he doesn't want to wait to see if he will make it to 80 to benefit from the agent if it's approved in five years. Instead he can come to our center."
Where are some of these researchers from?
The United States, the Czech Republic, Russia, Canada, and South America. I expect significantly more interest once we promote the idea of European products having a welcome niche in the Bahamas, because we accept federal approvals from the U.S., Canada, and the European Union.
What do you think will be the first medical breakthrough to come out of research there?
One of the biggest killers in the world is heart disease, and we have the opportunity to implement a number of cardiac protocols utilizing stem cell therapy, particularly for those with no options. We just completed a state-of-the art medical center that we fashioned after the University of Miami that is getting ready for prime time. The sky will be the limit for the cardiac patient with respect to stem cell medicine.
Second, we are extremely pleased to be involved with a company called Longeveron, which is looking at how one might age better, and age more slowly, particularly with the administration of young blood and mesenchymal stem cells to frail, elderly candidates. Healthy young men have their mesenchymal stem cells harvested, expanded, and then administered to frail, elderly individuals with a view to improving their Frailty Index and functionality (feeling younger). There is a lot of interest in this arena, as one could imagine.
And herein lies the classical scenario for the Bahamas: Longeveron is now recruiting patients for its phase IIB double blind, placebo-controlled clinical trial at multiple sites across the U.S., which will add some two to three years to its data collection. Originally this work was done with NIH support at the University of Miami's Interdisciplinary Stem Cell Institute by Dr. Joshua Hare, and published in the Journal of Gerontology. So now, during the ongoing and expanded clinical trial, with those positive signals, we are able to have a commercially available clinical registry in the Bahamas. This has been approved by the ethics committee here, which is comprised of international luminaries in regenerative medicine. Longeveron will also be conducting an additional randomized clinical trial arm of same at our Centre in The Bahamas, The Partners Stem Cell Centre.
Can you clarify what you mean by "registry"?
In other words, you still have to fit the eligibility criteria to receive the active agent, but the difference is that in a placebo-controlled double-blind clinical trial, the physician/researcher and the patient don't know if they are getting the active agent or placebo. In the registry, there is no placebo, and you know you're getting the active agent, what we call "open label." You're participating because of the previous information on efficacy and safety.
A person who is 75 and frail, he doesn't want to wait to see if he will make it to 80 to benefit from the agent if it's approved in five years. Instead he can come to our center, one of the designated centers, and as long as he meets the inclusion criteria, may participate in said registry. The additional data from our patients can bolster the numbers in the clinical trial, which can contribute to the FDA approval process. One can see how this could accelerate the process of discovery and acceptance, as well as prove if the agent was not as good as it was made out to be. It goes both ways.
"We would love to be known as a place that facilitates the acceleration of ethical science and ethical therapies, and therefore brings global relief to those in need."
Do you think one day the Bahamas will be more well-known for its science than its beaches?
I doubt that. What I would like to say is that the Bahamas would love to always be known for its beautiful beaches, but we would also like to be known for diversity and innovation. Apart from all that beauty, we can still play a welcoming role to the rest of the scientific world. We would love to be known as a place that facilitates the acceleration of ethical science and ethical therapies, and therefore brings global relief to those in need.
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.
Why Don’t We Have Artificial Wombs for Premature Infants?
Ectogenesis, the development of a baby outside of the mother's body, is a concept that dates back to 1923. That year, British biochemist-geneticist J.B.S. Haldane gave a lecture to the "Heretics Society" of the University of Cambridge in which he predicted the invention of an artificial womb by 1960, leading to 70 percent of newborns being born that way by the 2070s. In reality, that's about when an artificial womb could be clinically operational, but trends in science and medicine suggest that such technology would come in increments, each fraught with ethical and social challenges.
An extra-uterine support device could be ready for clinical trials in humans in the next two to four years, with hopes that it could improve survival of very premature infants.
Currently, one major step is in the works, a system called an extra-uterine support device (EUSD) –or sometimes Ex-Vivo uterine Environment (EVE)– which researchers at the Children's Hospital of Philadelphia have been using to support fetal lambs outside the mother. It also has been called an artificial placenta, because it supplies nutrient- and oxygen-rich blood to the developing lambs via the umbilical vein and receives blood full of waste products through the umbilical arteries. It does not do everything that a natural placenta does, yet it does do some things that a placenta doesn't do. It breathes for the fetus like the mother's lungs, and encloses the fetus in sterile fluid, just like the amniotic sac. It represents a solution to one set of technical challenges in the path to an artificial womb, namely how to keep oxygen flowing into a fetus and carbon dioxide flowing out when the fetal lungs are not ready to function.
Capable of supporting fetal lambs physiologically equivalent to a human fetus at 23 weeks' gestation or earlier, the EUSD could be ready for clinical trials in humans in the next two to four years, with hopes that it could improve survival of very premature infants. Existing medical technology can keep human infants alive when born in this 23-week range, or even slightly less —the record is just below 22 weeks. But survival is low, because most of the treatment is directed at the lungs, the last major body system to mature to a functional status. This leads to complications not only in babies born before 24 weeks' gestation, but also in a fairly large number of births up to 28 weeks' gestation.
So, the EUSD is basically an advanced neonatal life support machine that beckons to square off the survival curve for infants born up to the 28th week. That is no doubt a good thing, but given the political prominence of reproductive issues, might any societal obstacles be looming?
"While some may argue that the EUSD system will shift the definition of viability to a point prior to the maturation of the fetus' lungs, ethical and legal frameworks must still recognize the mother's privacy rights as paramount."
Health care attorney and clinical ethicist David N. Hoffman points out that even though the EUSD may shift the concept of fetal viability away from the maturity of developing lungs, it would not change the current relationship of the fetus to the mother during pregnancy.
"Our social and legal frameworks, including Roe v. Wade, invite the view of the embryo-fetus as resembling a parasite. Not in a negative sense, but functionally, since it obtains its life support from the mother, while she does not need the fetus for her own physical health," notes Hoffman, who holds faculty appointments at Columbia University, and at the Benjamin N. Cardozo School of Law and the Albert Einstein College of Medicine, of Yeshiva University. "In contrast, our ethical conception of the relationship is grounded in the nurturing responsibility of parenthood. We prioritize the welfare of both mother and fetus ethically, but we lean toward the side of the mother's legal rights, regarding her health throughout pregnancy, and her right to control her womb for most of pregnancy. While some may argue that the EUSD system will shift the definition of viability to a point prior to the maturation of the fetus' lungs, ethical and legal frameworks must still recognize the mother's privacy rights as paramount, on the basis of traditional notions of personhood and parenthood."
Outside of legal frameworks, religion, of course, is a major factor in how society reacts to new reproductive technologies, and an artificial womb would trigger a spectrum of responses.
"Significant numbers of conservative Christians may oppose an artificial womb in fear that it might harm the central role of marriage in Christianity."
Speaking from the perspective of Lutheran scholarship, Dr. Daniel Deen, Assistant Professor of Philosophy at Concordia University in Irvine, Calif., does not foresee any objections to the EUSD, either theologically, or generally from Lutherans (who tend to be conservative on reproductive issues), since the EUSD is basically an improvement on current management of prematurity. But things would change with the advent of a full-blown artificial womb.
"Significant numbers of conservative Christians may oppose an artificial womb in fear that it might harm the central role of marriage in Christianity," says Deen, who specializes in the philosophy of science. "They may see the artificial womb as a catalyst for strengthening the mechanistic view of reproduction that dominates the thinking of secular society, and of other religious groups, including more liberal Christians."
Judaism, however, appears to be more receptive, even during the research phases.
"Even if researchers strive for a next-generation EUSD aimed at supporting a fetus several weeks earlier than possible with the current system, it still keeps the fetus inside the mother well beyond the 40-day threshold, so there likely are no concerns in terms of Jewish law," says Kalman Laufer, a rabbinical student and executive director of the Medical Ethics Society at Yeshiva University. Referring to a concept from the Babylonian Talmud that an embryo is "like water" until 40 days into pregnancy, at which time it receives a kind of almost-human status warranting protection, Laufer cautions that he's speaking about artificial wombs developed for the sake of rescuing very premature infants. At the same time though, he expects that artificial womb research will eventually trigger a series of complex, legalistic opinions from Jewish scholars, as biotechnology moves further toward supporting fetal growth entirely outside a woman's body.
"Since [the EUSD] gives some justification to end abortion, by transferring fetuses from mother to machine, conservatives will probably rally around it."
While the technology treads into uncomfortable territory for social conservatives at first glance, it's possible that the prospect of taking the abortion debate in a whole new direction could engender support for the artificial womb. "Since [the EUSD] gives some justification to end abortion, by transferring fetuses from mother to machine, conservatives will probably rally around it," says Zoltan Istvan, a transhumanist politician and journalist who ran for U.S. president in 2016. To some extent, Deen agrees with Istvan, provided we get to a point when the artificial womb is already a reality.
"The world has a way of moving forward despite the fear of its inhabitants," Deen notes. "If the technology gets developed, I could not see any Christians, liberal or conservative, arguing that people seeking abortion ought not opt for a 'transfer' versus an abortive procedure."
So then how realistic is a full-blown artificial womb? The researchers at the Children's Hospital of Philadelphia have noted various technical difficulties that would come up in any attempt to connect a very young fetus to the EUSD and maintain life. One issue is the small umbilical cord blood vessels that must be connected to the EUSD as fetuses of decreasing gestational age are moved outside the mother. Current procedures might be barely adequate for integrating a human fetus into the device in the 18 -21 week range, but going to lower gestational ages would require new technology and different strategies. It also would require numerous other factors to cover for fetal body systems that mature ahead of the lungs and that the current EUSD system is not designed to replace. However, biotechnology and tissue engineering strategies on the horizon could be added to later EUSDs. To address the blood vessel size issue, artificial womb research could benefit by drawing on experts in microfluidics, the field concerned with manipulation of tiny amounts of fluid through very small spaces, and which is ushering in biotech innovations like the "lab on a chip".
"The artificial womb might put fathers on equal footing with mothers, since any embryo could potentially achieve personhood without ever seeing the inside of a woman's uterus."
If the technical challenges to an artificial womb are indeed overcome, reproductive policy debates could be turned on their side.
"Evolution of the EUSD into a full-blown artificial external uterus has ramifications for any reproductive rights issues where policy currently assumes that a mother is needed for a fertilized egg to become a person," says Hoffman, the ethicist and legal scholar. "If we consider debates over whether to keep cryopreserved human embryos in storage, destroy them, or utilize them for embryonic stem cell research or therapies, the artificial womb might put fathers on equal footing with mothers, since any embryo could potentially achieve personhood without ever seeing the inside of a woman's uterus."
Such a scenario, of course, depends on today's developments not being curtailed or sidetracked by societal objections before full-blown ectogenesis is feasible. But if this does ever become a reality, the history of other biotechnologies suggests that some segment of society will embrace the new innovation and never look back.