Is There a Blind Spot in the Oversight of Human Subject Research?
A scientist examining samples.
Human experimentation has come a long way since congressional hearings in the 1970s exposed patterns of abuse. Where yesterday's patients were protected only by the good conscience of physician-researchers, today's patients are spirited past hazards through an elaborate system of oversight and informed consent. Yet in many ways, the project of grounding human research on ethical foundations remains incomplete.
As human research has become a mainstay of career and commercial advancement among academics, research centers, and industry, new threats to research integrity have emerged.
To be sure, much of the medical research we do meets exceedingly high standards. Progress in cancer immunotherapy, or infectious disease, reflects the best of what can be accomplished when medical scientists and patients collaborate productively. And abuses of the earlier part of the 20th century--like those perpetrated by the U.S. Public Health Service in Guatemala--are for the history books.
Yet as human research has become a mainstay of career and commercial advancement among academics, research centers, and industry, new threats to research integrity have emerged. Many flourish in the blind spot of current oversight systems.
Take, for example, the tendency to publish only "positive" findings ("publication bias"). When patients participate in studies, they are told that their contributions will promote medical discovery. That can't happen if results of experiments never get beyond the hard drives of researchers. While researchers are often eager to publish trials showing a drug works, according to a study my own team conducted, fewer than 4 in 10 trials of drugs that never receive FDA approval get published. This tendency- which occurs in academia as well as industry- deprives other scientists of opportunities to build on these failures and make good on the sacrifice of patients. It also means the trials may be inadvertently repeated by other researchers, subjecting more patients to risks.
On the other hand, many clinical trials test treatments that have already been proven effective beyond a shadow of doubt. Consider the drug aprotinin, used for the management of bleeding during surgery. An analysis in 2005 showed that, not long after the drug was proven effective, researchers launched dozens of additional placebo-controlled trials. These redundant trials are far in excess of what regulators required for drug approval, and deprived patients in placebo arms of a proven effective therapy. Whether because of an oversight or deliberately (does it matter?), researchers conducting these trials often failed in publications to describe previous evidence of efficacy. What's the point of running a trial if no one reads the results?
It is surprisingly easy for companies to hijack research to market their treatments.
At the other extreme are trials that are little more than shots in the dark. In one case, patients with spinal cord injury were enrolled in a safety trial testing a cell-based regenerative medicine treatment. After the trial stopped (results were negative), laboratory scientists revealed that the cells had been shown ineffective in animal experiments. Though this information had been available to the company and FDA, researchers pursued the trial anyway.
It is surprisingly easy for companies to hijack research to market their treatments. One way this happens is through "seeding trials"- studies that are designed not to address a research question, but instead to habituate doctors to using a new drug and to generate publications that serve as advertisements. Such trials flood the medical literature with findings that are unreliable because studies are small and not well designed. They also use the prestige of science to pursue goals that are purely commercial. Yet because they harm science- not patients (many such studies are minimally risky because all patients receive proven effective medications)- ethics committees rarely block them.
Closely related is the phenomenon of small uninformative trials. After drugs get approved by the FDA, companies often launch dozens of small trials in new diseases other than the one the drug was approved to treat. Because these studies are small, they often overestimate efficacy. Indeed, the way trials are often set up, if a company tests an ineffective drug in 40 different studies, one will typically produce a false positive by chance alone. Because companies are free to run as many trials as they like and to circulate "positive" results, they have incentives to run lots of small trials that don't provide a definitive test of their drug's efficacy.
Universities, funding bodies, and companies should be scored by a neutral third-party based on the impact of their trials -- like Moody's for credit ratings.
Don't think public agencies are much better. Funders like the National Institutes of Health secure their appropriations by gratifying Congress. This means that NIH gets more by spreading its funding among small studies in different Congressional districts than by concentrating budgets among a few research institutions pursuing large trials. The result is that some NIH-funded clinical trials are not especially equipped to inform medical practice.
It's tempting to think that FDA, medical journals, ethics committees, and funding agencies can fix these problems. However, these practices continue in part because FDA, ethics committees, and researchers often do not see what is at stake for patients by acquiescing to low scientific standards. This behavior dishonors the patients who volunteer for research, and also threatens the welfare of downstream patients, whose care will be determined by the output of research.
To fix this, deficiencies in study design and reporting need to be rendered visible. Universities, funding bodies, and companies should be scored by a neutral third-party based on the impact of their trials, or the extent to which their trials are published in full -- like Moody's for credit ratings, or the Kelley Blue Book for cars. This system of accountability would allow everyone to see which institutions make the most of the contributions of research subjects. It could also harness the competitive instincts of institutions to improve research quality.
Another step would be for researchers to level with patients when they enroll in studies. Patients who agree to research are usually offered bromides about how their participation may help future patients. However, not all studies are created equal with respect to merit. Patients have a right to know when they are entering studies that are unlikely to have a meaningful impact on medicine.
Ethics committees and drug regulators have done a good job protecting research volunteers from unchecked scientific ambition. However, today's research is plagued by studies that have poor scientific credentials. Such studies free-ride on the well-earned reputation of serious medical science. They also potentially distort the evidence available to physicians and healthcare systems. Regulators, academic medical centers, and others should establish policies that better protect human research volunteers by protecting the quality of the research itself.
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.
Podcast: The Friday Five weekly roundup in health research
This week's Friday Five covers promising research on a potential saliva test for post-traumatic stress disorder, cancer detection with a microchip, resilient food for climate change, the best posture for pill taking, and more.
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
Here are the promising studies covered in this week's Friday Five:
- Using graphene to repair shoulders
- Testing for PTSD with saliva
- Cancer detection with a microchip
- Best posture for pill taking
- Resilient food for climate change
And an honorable mention goes to research on a new way to induce healthy fat.