Researchers advance drugs that treat pain without addiction
New therapies are using creative approaches that target the body’s sensory neurons, which send pain signals to the brain.
Opioids are one of the most common ways to treat pain. They can be effective but are also highly addictive, an issue that has fueled the ongoing opioid crisis. In 2020, an estimated 2.3 million Americans were dependent on prescription opioids.
Opioids bind to receptors at the end of nerve cells in the brain and body to prevent pain signals. In the process, they trigger endorphins, so the brain constantly craves more. There is a huge risk of addiction in patients using opioids for chronic long-term pain. Even patients using the drugs for acute short-term pain can become dependent on them.
Scientists have been looking for non-addictive drugs to target pain for over 30 years, but their attempts have been largely ineffective. “We desperately need alternatives for pain management,” says Stephen E. Nadeau, a professor of neurology at the University of Florida.
A “dimmer switch” for pain
Paul Blum is a professor of biological sciences at the University of Nebraska. He and his team at Neurocarrus have created a drug called N-001 for acute short-term pain. N-001 is made up of specially engineered bacterial proteins that target the body’s sensory neurons, which send pain signals to the brain. The proteins in N-001 turn down pain signals, but they’re too large to cross the blood-brain barrier, so they don’t trigger the release of endorphins. There is no chance of addiction.
When sensory neurons detect pain, they become overactive and send pain signals to the brain. “We wanted a way to tone down sensory neurons but not turn them off completely,” Blum reveals. The proteins in N-001 act “like a dimmer switch, and that's key because pain is sensation overstimulated.”
Blum spent six years developing the drug. He finally managed to identify two proteins that form what’s called a C2C complex that changes the structure of a subunit of axons, the parts of neurons that transmit electrical signals of pain. Changing the structure reduces pain signaling.
“It will be a long path to get to a successful clinical trial in humans," says Stephen E. Nadeau, professor of neurology at the University of Florida. "But it presents a very novel approach to pain reduction.”
Blum is currently focusing on pain after knee and ankle surgery. Typically, patients are treated with anesthetics for a short time after surgery. But anesthetics usually only last for 4 to 6 hours, and long-term use is toxic. For some, the pain subsides. Others continue to suffer after the anesthetics have worn off and start taking opioids.
N-001 numbs sensation. It lasts for up to 7 days, much longer than any anesthetic. “Our goal is to prolong the time before patients have to start opioids,” Blum says. “The hope is that they can switch from an anesthetic to our drug and thereby decrease the likelihood they're going to take the opioid in the first place.”
Their latest animal trial showed promising results. In mice, N-001 reduced pain-like behaviour by 90 percent compared to the control group. One dose became effective in two hours and lasted a week. A high dose had pain-relieving effects similar to an opioid.
Professor Stephen P. Cohen, director of pain operations at John Hopkins, believes the Neurocarrus approach has potential but highlights the need to go beyond animal testing. “While I think it's promising, it's an uphill battle,” he says. “They have shown some efficacy comparable to opioids, but animal studies don't translate well to people.”
Nadeau, the University of Florida neurologist, agrees. “It will be a long path to get to a successful clinical trial in humans. But it presents a very novel approach to pain reduction.”
Blum is now awaiting approval for phase I clinical trials for acute pain. He also hopes to start testing the drug's effect on chronic pain.
Learning from people who feel no pain
Like Blum, a pharmaceutical company called Vertex is focusing on treating acute pain after surgery. But they’re doing this in a different way, by targeting a sodium channel that plays a critical role in transmitting pain signals.
In 2004, Stephen Waxman, a neurology professor at Yale, led a search for genetic pain anomalies and found that biologically related people who felt no pain despite fractures, burns and even childbirth had mutations in the Nav1.7 sodium channel. Further studies in other families who experienced no pain showed similar mutations in the Nav1.8 sodium channel.
Scientists set out to modify these channels. Many unsuccessful efforts followed, but Vertex has now developed VX-548, a medicine to inhibit Nav1.8. Typically, sodium ions flow through sodium channels to generate rapid changes in voltage which create electrical pulses. When pain is detected, these pulses in the Nav1.8 channel transmit pain signals. VX-548 uses small molecules to inhibit the channel from opening. This blocks the flow of sodium ions and the pain signal. Because Nav1.8 operates only in peripheral nerves, located outside the brain, VX-548 can relieve pain without any risk of addiction.
"Frankly we need drugs for chronic pain more than acute pain," says Waxman.
The team just finished phase II clinical trials for patients following abdominoplasty surgery and bunionectomy surgery.
After abdominoplasty surgery, 76 patients were treated with a high dose of VX-548. Researchers then measured its effectiveness in reducing pain over 48 hours, using the SPID48 scale, in which higher scores are desirable. The score for Vertex’s drug was 110.5 compared to 72.7 in the placebo group, whereas the score for patients taking an opioid was 85.2. The study involving bunionectomy surgery showed positive results as well.
Waxman, who has been at the forefront of studies into Nav1.7 and Nav1.8, believes that Vertex's results are promising, though he highlights the need for further clinical trials.
“Blocking Nav1.8 is an attractive target,” he says. “[Vertex is] studying pain that is relatively simple and uniform, and that's key to having a drug trial that is informative. But the study needs to be replicated and frankly we need drugs for chronic pain more than acute pain. If this is borne out by additional studies, it's one important step in a journey.”
Vertex will be launching phase III trials later this year.
Finding just the right amount of Nerve Growth Factor
Whereas Neurocarrus and Vertex are targeting short-term pain, a company called Levicept is concentrating on relieving chronic osteoarthritis pain. Around 32.5 million Americans suffer from osteoarthritis. Patients commonly take NSAIDs, or non-steroidal anti-inflammatory drugs, but they cannot be taken long-term. Some take opioids but they aren't very effective.
Levicept’s drug, Levi-04, is designed to modify a signaling pathway associated with pain. Nerve Growth Factor (NGF) is a neurotrophin: it’s involved in nerve growth and function. NGF signals by attaching to receptors. In pain there are excess neurotrophins attaching to receptors and activating pain signals.
“What Levi-04 does is it returns the natural equilibrium of neurotrophins,” says Simon Westbrook, the CEO and founder of Levicept. It stabilizes excess neurotrophins so that the NGF pathway does not signal pain. Levi-04 isn't addictive since it works within joints and in nerves outside the brain.
Westbrook was initially involved in creating an anti-NGF molecule for Pfizer called Tanezumab. At first, Tanezumab seemed effective in clinical trials and other companies even started developing their own versions. However, a problem emerged. Tanezumab caused rapidly progressive osteoarthritis, or RPOA, in some patients because it completely removed NGF from the system. NGF is not just involved in pain signalling, it’s also involved in bone growth and maintenance.
Levicept has found a way to modify the NGF pathway without completely removing NGF. They have now finished a small-scale phase I trial mainly designed to test safety rather than efficacy. “We demonstrated that Levi-04 is safe and that it bound to its target, NGF,” says Westbrook. It has not caused RPOA.
Professor Philip Conaghan, director of the Leeds Institute of Rheumatic and Musculoskeletal Medicine, believes that Levi-04 has potential but urges the need for caution. “At this early stage of development, their molecule looks promising for osteoarthritis pain,” he says. “They will have to watch out for RPOA which is a potential problem.”
Westbrook starts phase II trials with 500 patients this summer to check for potential side effects and test the drug’s efficacy.
There is a real push to find an effective alternative to opioids. “We have a lot of work to do,” says Professor Waxman. “But I am confident that we will be able to develop new, much more effective pain therapies.”
Scientists Just Created Liquid Solar Power That Can Be Stored for 18 Years
A team of Swedish scientists has gathered solar power so pure, that until recently, capturing it was an impossibility.
Look no further than this week's climate strikes for evidence that millions of people are passionate about curbing global warming.
Unlike relatively limited solar panel energy storage, norbornadiene can potentially maintain its potency for years.
But even potential solutions, like alternative meats, have their own challenges. Some scientists are putting their focus on the sun to help balance out our energy consumption.
In fact, they are gathering solar power so pure that, until recently, capturing it was an impossibility.
The Lowdown
A group of Swedish scientists has created a liquid called norbornadiene. This liquid sunshine can capture up to 30 percent of raw solar power. To put it in perspective, the best publicly available solar panels can harness 21 percent. Norbornadiene would bring in about 50 percent more power – a significant difference in energy efficiency.
Most notably, unlike relatively limited solar panel energy storage, norbornadiene can potentially maintain its potency for years. We could have the ability to collect and store premium solar power, making it easier for current and future generations to use fossil and nuclear fuel alternatives.
"The norbornadiene molecules that we have made have very good properties, in terms of solar energy capture efficiency, storage time and energy density," says team lead Dr. Kasper Moth-Poulson of the Chamlers University of Technology. "They can store energy without the need for insulation materials for 18 or more years."
Next Up
Swedish scientist Moth-Poulsen and his team have been testing the norbornadiene on the physics building roof at the Chalmers University of Technology. Once activated, it heats up to just below boiling and provides enough power to be useful.
The energy density is 250 watt-hours per kilogram, twice the strength of Tesla's popular Powerall battery.
It requires potentially toxic solvents, like a cobalt-based activator, to transform into its full potential. The team is currently trying to find less-hazardous catalysts to help transform the norbornadiene to its active form, quadricyclane. Exposing it to sunlight is the main way to reactivate the norbornadiene's power. Over time, scientists will likely make it more efficient with less toxic agents.
The energy density is 250 watt-hours per kilogram, twice the strength of Tesla's popular Powerall battery.
Open Questions
The biggest question is safety, perceived or otherwise: Are you ready to drive around with 250 kWh of pure solar in your Hyundai? Norbornadiene may be stable in a hermetically sealed lab, but sculpting it for everyday use requires another level of security.
The half-life of the sunshine power is also an estimate, too. The challenge with new scientific substances is you don't know how the matter will evolve over time. It is easy to be overly optimistic about this one discovery being the key to our energy needs. For the time being, it is wiser to look at norbornadiene as a progressive step rather than a revolutionary one.
Even at its least effective, norbornadiene and its related material is a step toward us utilizing the one natural resource that won't run out for generations. In the short-term, a stable form of it could offset our fossil and nuclear fuel use and even help lower the carbon footprint made by long-distance transportation. It will be fascinating to see what future aircraft builders, home designers and even car manufacturers do as the solar technology conversation heats up.
Moth-Poulsen wants norbornadiene to be a definitive part of the climate change puzzle.
"I hope that in five years, we will see the first products based on our molecules and could help mitigate the daily variations in temperature," he says. "This will lead to increased thermal comfort and reduced energy consumption for heating and cooling."
Virtual Reality is Making Medical Care for Kids Less Scary and Painful
A patient at Children's Hospital Los Angeles (Courtesy of Children's Hospital Los Angeles) plus Bear Blast, developed by AppliedVR.
A blood draw is not normally a fun experience, but these days, virtual reality technology is changing that.
Instead of watching a needle go into his arm, a child wearing a VR headset at Children's Hospital Los Angeles can play a game throwing balls at cartoon bears. In Seattle, at the University of Washington, a burn patient can immerse herself in a soothing snow scene. And at the University of Miami Hospital, a five-minute skin biopsy can become an exciting ride at an amusement park.
VR is transforming once-frightening medical encounters for kids, from blood draws to biopsies to pre-surgical prep, into tolerable ones.
It's literally a game changer, says pediatric neurosurgeon Kurtis Auguste, who uses the tool to help explain pending operations to his young patients and their families. The virtual reality 3-D portrait of their brain is recreated from an MRI, originally to help plan the surgery. The image of normally bland tissue is painted with false colors to better see the boundaries and anomalies of each component. It can be rotated, viewed from every possible angle, zoomed in and out; incisions can be made and likely results anticipated. Auguste has extended its use to patients and families.
"The moment you put these headsets on the kids, we immediately have a link, because honestly, this is how they communicate with each other," says Auguste. "We're all sitting around the table playing games. It's really bridged the distance between me, the pediatric specialist, and my patients" at the Benioff Children's Hospital Oakland, now affiliated with the University of California San Francisco School of Medicine.
The VR experience engages people where they are, immersing them in the environment rather than lecturing them. And it seems to work in all environments, across age and cultural differences, leading to a better grasp of what will be undertaken. That understanding is crucial to meaningful informed consent for surgery. It is particularly relevant for safety-net hospitals, which includes most children's hospitals, because often members of the families were born elsewhere and may have limited understanding of English, not to mention advanced medicine.
Targeting pain
"We're trying to target ways that we can decrease pain, anxiety, fear – what people usually experience as a function of a needle," says Jeffrey Gold, a pioneer in adapting VR at Children's Hospital Los Angeles. He ran the pain clinic there and in 2004 initially focused on phlebotomy, simple blood draws. Many of their kids require frequent blood draws to monitor serious chronic conditions such as diabetes, HIV infection, sickle cell disease, and other conditions that affect the heart, liver, kidneys and other organs.
The scientific explanation of how VR works for pain relief draws upon two basic principles of brain function. The first is "top down inhibition," Gold explains. "We all have the inherent capacity to turn down signals once we determine that signal is no longer harmful, dangerous, hurtful, etc. That's how our brain operates on purpose. It's not just a distraction, it's actually your brain stopping the pain signal at the spinal cord before it can fire all the way up to the frontal lobe."
Second is the analgesic effect from endorphins. "If you're in a gaming environment, and you're having fun and you're laughing and giggling, you are actually releasing endorphins...a neurochemical reaction at the synaptic level of the brain," he says.
Part of what makes VR effective is "what's called a cognitive load, where you have to actually learn something and do something," says Gold. He has worked with developers on a game call Bear Blast, which has proven to be effective in a clinical trial for mitigating pain. But he emphasizes, it is not a one-size-fits all; the programs and patients need to be evaluated to understand what works best for each case.
Gold was a bit surprised to find that VR "actually facilitates quicker blood draws," because the staff doesn't have to manage the kids' anxiety, so "they require fewer needle sticks." The kids, parents, and staff were all having a good time, "and that's a big win when everybody is benefiting." About two years ago the hospital made VR an option that patients can request in the phlebotomy lab, and about half of kids age 4 and older choose to do so.
The technology "gets the kids engaged and performing the activity the way we want them to" to maximize recovery.
VR reduces or eliminates the need to use sedation or anesthesia, which carries a small but real risk of an adverse reaction. And important to parents, it eliminates the recovery time from using sedation, which shortens the visit and time missed from school and work.
A more intriguing question is whether reducing fear and anxiety in early-life experiences with the healthcare system through activities like VR will have a long-term affect on kids' attitudes toward medicine as they grow older. "If you're a screaming meemie when you come get your blood draw when you're five or seven, you're still that anxious adolescent or adult who is all quivering and sweating and avoiding healthcare," Gold says. "That's a longitudinal health outcome I'd love to get my hands on in 10-15 years from now."
Broader applications
Dermatologist Hadar Lev-Tov read about the use of VR to treat pain and decided to try it in his practice at the University of Miami Hospital. He thought, "OK, this is low risk, it's easy to do. So we got some equipment and got it done." It was so affordable he paid for it out of his own pocket, rather than wait to go through administrative channels. The results were so interesting that he decided to publish it as a series of case studies with a wide variety of patients and types of procedures.
Some of them, such as freezing off warts, are not particularly painful. "But there can be a lot of anxiety, especially for kids, which can be worse than pain and can disrupt the procedure." It can trigger a non-rational, primal fight or flight response in the limbic region of the brain.
Adults understand the need for a biopsy of a skin growth and tolerate what might be a momentary flick of pain. "But for a kid you think twice about a biopsy, both because it's a hassle and because it could be a traumatic event for a child," says Lev-Tov. VR has helped to allay such fears and improve medical care.
Integrating VR into practice has been relatively easy, primarily focusing on simple training for staff and ensuring that standard infection control practices are used in handling equipment that is used by different patients. More mundane issues are ensuring that the play back and wi-fi equipment are functioning properly. He has had a few complaints from kids when the procedure is competed and the VR is turned off prematurely, which is why he favors programs like a roller coaster ride that lasts about five minutes, ample time to take a biopsy or two.
The future is today
The pediatric neurosurgeon Auguste is collaborating with colleagues at Oakland Children's to expand use of VR into different areas of care. Cancer specialists often use a port, a bubble installed under the skin in the chest of the child, to administer chemotherapy. But the young patient's curiosity often draws their attention downward to the port and their chin can potentially contaminate or obstruct it, interfering with the procedure. So the team developed a VR game involving birds that requires players to move their heads upward, away from the port, improving administration of the drugs and reducing the risk of infection.
Innovative use of VR just may be one tool that actually makes kids eager to visit the doctor.
Other games are being developed for rehabilitation that require the use of specific nerve and muscle combinations. The technology "gets the kids engaged and performing the activity the way we want them to" to maximize recovery, Auguste explains. "We can monitor their progress by the score on the game, and if it plateaus, maybe switch to another game."
Another project is trying to ease the anxiety and confusion of the patient and family experience within the hospital itself. Hospital staff are creating a personalized VR introductory walking tour that leads from the parking garage through the maze of structures and corridors in the hospital complex to Dr. Auguste's office, phlebotomy, the MRI site, and other locations they might visit. The goal is to make them familiar with key landmarks before they even set foot in the facility. "So when they come the day of the visit they have already taken that exact same path, hopefully more than once."
"They don't miss their MRI appointment and therefore they don't miss their clinical appointment with me," says Auguste. It reduces patient anxiety about the encounter and from the hospital's perspective, it will reduce costs of missed and rescheduled visits simply because patients did not go to the right place at the right time.
The VR visit will be emailed to patients ahead of time and they can watch it on a smartphone installed in a disposable cardboard viewer. Oakland Children's hopes to have the system in place by early next year. Auguste says their goal in using VR, like other health care providers across the country, is "to streamline the entire patient experience."
Innovative use of VR just may be one tool that actually makes kids eager to visit the doctor. That would be a boon to kids, parents, and the health of America.