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.”
The Nation’s Science and Health Agencies Face a Credibility Crisis: Can Their Reputations Be Restored?
Morale at federal science agencies -- and public trust in their guidance -- is at a concerning low right now.
This article is part of the magazine, "The Future of Science In America: The Election Issue," co-published by LeapsMag, the Aspen Institute Science & Society Program, and GOOD.
It didn't have to be this way. More than 200,000 Americans dead, seven million infected, with numbers continuing to climb, an economy in shambles with millions out of work, hundreds of thousands of small businesses crushed with most of the country still under lockdown. And all with no end in sight. This catastrophic result is due in large part to the willful disregard of scientific evidence and of muzzling policy experts by the Trump White House, which has spent its entire time in office attacking science.
One of the few weapons we had to combat the spread of Covid-19—wearing face masks—has been politicized by the President, who transformed this simple public health precaution into a first amendment issue to rally his base. Dedicated public health officials like Dr. Anthony Fauci, the highly respected director of the National Institute of Allergies and Infectious Diseases, have received death threats, which have prompted many of them around the country to resign.
Over the summer, the Trump White House pressured the Centers for Disease Control, which is normally in charge of fighting epidemics, to downplay COVID risks among young people and encourage schools to reopen. And in late September, the CDC was forced to pull federal teams who were going door-to-door doing testing surveys in Minnesota because of multiple incidents of threats and abuse. This list goes on and on.
Still, while the Trump administration's COVID failures are the most visible—and deadly—the nation's entire federal science infrastructure has been undermined in ways large and small.
The White House has steadily slashed monies for science—the 2021 budget cuts funding by 10–30% or more for crucial agencies like National Oceanic and Atmospheric Administration (NOAA) and the Environmental Protection Agency (EPA)—and has gutted health and science agencies across the board, including key agencies of the Department of Energy and the Interior, especially in divisions that deal with issues they oppose ideologically like climate change.
Even farmers can't get reliable information about how climate change affects planting seasons because the White House moved the entire staff at the U.S. Department of Agriculture agency who does this research, relocating them from Maryland to Kansas City, Missouri. Many of these scientists couldn't uproot their families and sell their homes, so the division has had to pretty much start over from scratch with a skeleton crew.
More than 1,600 federal scientists left government in the first two years of the Trump Administration, according to data compiled by the Washington Post, and one-fifth of top positions in science are vacant, depriving agencies of the expertise they need to fulfill their vital functions. Industry executives and lobbyists have been installed as gatekeepers—HHS Secretary Alex Azar was previously president of Eli Lilly, and three climate change deniers were appointed to key posts at the National Oceanic and Atmospheric Administration, to cite just a couple of examples. Trump-appointed officials have sidelined, bullied, or even vilified those who dare to speak out, which chills the rigorous debate that is the essential to sound, independent science.
"The CDC needs to be able to speak regularly to the American people to explain what it knows and how it knows it."
Linda Birnbaum knows firsthand what it's like to become a target. The microbiologist recently retired after more than a decade as the director of the National Institute of Environmental Health Sciences, which is the world's largest environmental health organization and the greatest funder of environmental health and toxicology research, a position that often put her agency at odds with the chemical and fossil fuel industry. There was an attempt to get her fired, she says, "because I had the nerve to write that science should be used in making policy. The chemical industry really went after me, and my last two years were not so much fun under this administration. I'd like to believe it was because I was making a difference—if I wasn't, they wouldn't care."
Little wonder that morale at federal agencies is low. "We're very frustrated," says Dr. William Schaffner, a veteran infectious disease specialist and a professor of medicine at the Vanderbilt University School of Medicine in Nashville. "My colleagues within these agencies, the CDC rank and file, are keeping their heads down doing the best they can, and they hope to weather this storm."
The cruel irony is that the United States was once a beacon of scientific innovation. In the heady post World War II years, while Europe lay in ruins, the successful development of penicillin and the atomic bomb—which Americans believed helped vanquish the Axis powers—unleashed a gusher of public money into research, launching an unprecedented era of achievement in American science. Scientists conquered polio, deciphered the genetic code, harnessed the power of the atom, invented lasers, transistors, microchips and computers, sent missions beyond Mars, and landed men on the moon. A once-inconsequential hygiene laboratory was transformed into the colossus the National Institutes of Health has become, which remains today the world's flagship medical research center, unrivaled in size and scope.
At the same time, a tiny public health agency headquartered in Atlanta, which had been in charge of eradicating the malaria outbreaks that plagued impoverished rural areas in the Deep South until the late 1940s, evolved into the Centers for Disease Control and Prevention. The CDC became the world's leader in fighting disease outbreaks, and the agency's crack team of epidemiologists—members of the vaunted Epidemic Intelligence Service—were routinely dispatched to battle global outbreaks of contagions such as Ebola and malaria and help lead the vaccination campaigns to eradicate killers like polio and small pox that have saved millions of lives.
What will it take to rebuild our federal science infrastructure and restore not only the public's confidence but the respect of the world's scientific community? There are some hopeful signs that there is pushback against the current national leadership, and non-profit watchdog groups like the Union of Concerned Scientists have mapped out comprehensive game plans to restore public trust and the integrity of science.
These include methods of protecting science from political manipulation; restoring the oversight role of independent federal advisory committees, whose numbers were decimated by recent executive orders; strengthening scientific agencies that have been starved by budget cuts and staff attrition; and supporting whistleblower protections and allowing scientists to do their jobs without political meddling to restore integrity to the process. And this isn't just a problem at the CDC. A survey of 1,600 EPA scientists revealed that more than half had been victims of political interference and were pressured to skew their findings, according to research released in April by the Union of Concerned Scientists.
"Federal agencies are staffed by dedicated professionals," says Andrew Rosenberg, director of the Center for Science and Democracy at the Union of Concerned Scientists and a former fisheries biologist for NOAA. "Their job is not to serve the president but the public interest. Inspector generals are continuing to do what they're supposed to, but their findings are not being adhered to. But they need to hold agencies accountable. If an agency has not met its mission or engaged in misconduct, there needs to be real consequences."
On other fronts, last month nine vaccine makers, including Sanofi, Pfizer, and AstraZeneca, took the unprecedented stop of announcing that their COVID-19 vaccines would be thoroughly vetted before they were released. In their implicit refusal to bow to political pressure from the White House to have a vaccine available before the election, their goal was to restore public confidence in vaccine safety, and ensure that enough Americans would consent to have the shot when it was eventually approved so that we'd reach the long-sought holy grail of herd immunity.
"That's why it's really important that all of the decisions need to be made with complete transparency and not taking shortcuts," says Dr. Tom Frieden, president and CEO of Resolve to Save Lives and former director of the CDC during the H1N1, Ebola, and Zika emergencies. "A vaccine is our most important tool, and we can't break that tool by meddling in the science approval process."
In late September, Senate Democrats introduced a new bill to halt political meddling in public health initiatives by the White House. Called Science and Transparency Over Politics Act (STOP), the legislation would create an independent task force to investigate political interference in the federal response to the coronavirus pandemic. "The Trump administration is still pushing the president's political priorities rather than following the science to defeat this virus," Senate Minority Leader Chuck Schumer said in a press release.
To effectively bring the pandemic under control and restore public confidence, the CDC must assume the leadership role in fighting COVID-19. During previous outbreaks, the top federal infectious disease specialists like Drs. Fauci and Frieden would have daily press briefings, and these need to resume. "The CDC needs to be able to speak regularly to the American people to explain what it knows and how it knows it," says Frieden, who cautions that a vaccine won't be a magic bullet. "There is no one thing that is going to make this virus go away. We need to continue to limit indoor exposures, wear masks, and do strategic testing, isolation, and quarantine. We need a comprehensive approach, and not just a vaccine."
We must also appoint competent and trustworthy leaders, says Rosenberg of the Union of Concerned Scientists. Top posts in too many science agencies are now filled by former industry executives and lobbyists with a built-in bias, as well as people lacking relevant scientific experience, many of whom were never properly vetted because of the current administration's penchant for bypassing Congress and appointing "acting" officials. "We've got great career people who have hung in, but in so much of the federal government, they just put in 'acting' people," says Linda Birnbaum. "They need to bring in better, qualified senior leadership."
Open positions need to be filled, too. Federal science agencies have been seriously crippled by staffing attrition, and the Trump Administration instituted a hiring freeze when it first came in. Staffing levels remain at least ten percent down from previous levels, says Birnbaum and in many agencies, like the EPA, "everything has come to a screeching halt, making it difficult to get anything done."
But in the meantime, the critical first step may be at the ballot box in November. Even Scientific American, the esteemed consumer science publication, for the first time in its 175-year history felt "compelled" to endorse a presidential candidate, Joe Biden, because of the enormity of the damage they say Donald Trump has inflicted on scientists, their legal protections, and on the federal science agencies.
"If the current administration continues, the national political leadership will be emboldened and will be even more assertive of their executive prerogatives and less concerned about traditional niceties, leading to further erosion of the activities of many federal agencies," says Vanderbilt's William Schaffner. "But the reality is, if the team is losing, you change the coach. Then agencies really have to buckle down because it will take some time to restore their hard-earned reputations."
[Editor's Note: To read other articles in this special magazine issue, visit the beautifully designed e-reader version.]
Announcing "The Future of Science in America: The Election Issue"
This special magazine explores what's at stake for science & policy over the next four years.
As reviewed in The Washington Post, "Tomorrow's challenges in science and politics: Magazine offers in-depth takes on these U.S. issues":
"Is it time for a new way to help make adults more science-literate? What should the next president know about science? Could science help strengthen American democracy? "The Future of Science in America: The Election Issue" has answers. The free, online magazine is packed with interesting takes on how science can serve the common good. And just in time. This year has challenged leaders, researchers and the public with thorny scientific questions, from the coronavirus pandemic to widespread misinformation on scientific issues. The magazine is a collaboration of the Aspen Institute, a think tank that brings together a variety of public figures and private individuals to tackle thorny social issues, the digital science magazine Leapsmag and GOOD, a social impact company. It's packed with 15 in-depth articles about science with a view toward our campaign year."
The Future of Science in America: The Election Issue offers wide-ranging perspectives on challenges and opportunities for science as we elect our next national and local leaders. The fast-striking COVID-19 pandemic and the more slowly moving pandemic of climate change have brought into sharp focus how reliant we will be on science and public policy to work together to rescue us from crisis. Doing so will require cooperation between both political parties, as well as significant public trust in science as a beacon to light the path forward.
In spite of its unfortunate emergence as a flash point between two warring parties, we believe that science is the driving force for universal progress. No endeavor is more noble than the quest to rigorously understand our world and apply that knowledge to further human flourishing. This magazine aspires to promote roadmaps for science as a tool for health, a vehicle for progress, and a unifier of our nation.
This special issue is a collaboration among LeapsMag, the Aspen Institute Science & Society Program, and GOOD, with support from the Gordon and Betty Moore Foundation and the Rita Allen Foundation.
It is available as a free, beautifully designed digital magazine for both desktop and mobile.
TABLE OF CONTENTS:
- SCIENTISTS:
Award-Winning Scientists Offer Advice to the Next President of the United States - PUBLIC OPINION:
National Survey Reveals Americans' Most Important Scientific Priorities - GOVERNMENT:
The Nation's Science and Health Agencies Face a Credibility Crisis: Can Their Reputations Be Restored? - TELEVISION:
To Make Science Engaging, We Need a Sesame Street for Adults - IMMIGRATION:
Immigrant Scientists—and America's Edge—Face a Moment of Truth This Election - RACIAL JUSTICE:
Democratize the White Coat by Honoring Black, Indigenous, and People of Color in Science - EDUCATION:
I'm a Black, Genderqueer Medical Student: Here's My Hard-Won Wisdom for Students and Educational Institutions - TECHNOLOGY:
"Deep Fake" Video Technology Is Advancing Faster Than Our Policies Can Keep Up - VOTERS:
Mind the (Vote) Gap: Can We Get More STEM Students to the Polls? - EXPERTS:
Who Qualifies as an "Expert" and How Can We Decide Who Is Trustworthy? - SOCIAL MEDIA:
Why Your Brain Falls for Misinformation—And How to Avoid It - YOUTH:
Youth Climate Activists Expand Their Focus and Collaborate to Get Out the Vote - SUPREME COURT:
Abortions Before Fetal Viability Are Legal: Might Science and a Change on the Supreme Court Undermine That? - NAVAJO NATION:
An Environmental Scientist and an Educator Highlight Navajo Efforts to Balance Tradition with Scientific Priorities - CIVIC SCIENCE:
Want to Strengthen American Democracy? The Science of Collaboration Can Help
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.