A hidden pocket that opens only the good pathways
In the long shadow of the opioid crisis, a coalition of researchers has received $3.9 million from the National Institutes of Health to pursue a fundamentally different relationship between medicine and pain — one that seeks relief without the chains of addiction. Scientists at Sanford Burnham Prebys, Duke University, and the University of Minnesota are refining SBI-810, a molecule that enters a hidden pocket of a brain receptor rather than its front door, coaxing the body toward comfort while bypassing the pathways that have made opioids so destructive. The work speaks to one of modern medicine's most urgent moral reckonings: that tens of millions of Americans live in pain, and the tools we have to help them too often cause a different kind of harm.
- Eighty percent of the 19 million Americans who undergo major surgery each year wake up in serious pain — and the drugs most reliably on hand to treat them carry the risk of addiction and death.
- SBI-810 exploits a hidden interior pocket on the neurotensin receptor 1, redirecting its signaling like a hand quietly rerouting traffic rather than forcing open a gate — producing morphine-level relief without the blood pressure crashes that doomed earlier attempts.
- Back-to-back 2025 studies in Cell and Nature have given the compound unusual scientific credibility, demonstrating efficacy across multiple pain models and revealing the precise molecular architecture that makes the mechanism work — and replicable.
- The NIH grant is structured as a two-year sprint toward human trials, with an additional $4 million contingent on hitting milestones, and a Phase 1 safety trial in healthy volunteers as the near-term horizon.
- A remaining cardiac safety concern and the need to understand sex-based differences in drug response are the live obstacles standing between the lab and the clinic.
The National Institute of Neurological Disorders and Stroke has committed $3.9 million to a research team pursuing a pain treatment that sidesteps the addiction and overdose risks that have made opioids so dangerous. The funding, part of the NIH's Healing to End Addiction Long-term initiative, supports scientists at Sanford Burnham Prebys Medical Discovery Institute, Duke University, and the University of Minnesota as they refine a molecule called SBI-810 and move it toward human testing.
The scale of the problem is staggering. Roughly 80 percent of the 19 million Americans who undergo major surgery each year wake up in significant pain, and another 25 million live with chronic pain that never fully resolves. Opioids — the dominant tool for managing that suffering — often fail to control pain adequately while introducing catastrophic risks of their own. The researchers see an opening in a brain and nervous system receptor called neurotensin receptor 1, or NTR1, whose natural activating molecule was known decades ago to produce pain relief more powerful than morphine. The obstacle was that drugs targeting NTR1 directly caused dangerous drops in blood pressure and body temperature.
SBI-810 takes a different path. Rather than binding to the receptor's main active site, it slips into a hidden interior pocket, acting as what researchers call a biased allosteric modulator — selectively activating beneficial signaling pathways while suppressing pain-promoting ones. The result is potent relief without the cardiovascular side effects that derailed earlier attempts. The compound also showed promise in reducing opioid-related symptoms like constipation and withdrawal, suggesting it could complement existing pain management rather than simply replace it.
The scientific foundation is unusually strong. A 2025 study in Cell demonstrated SBI-810's efficacy across multiple animal pain models — postoperative, inflammatory, and neuropathic — and showed it suppressed pain signaling in human sensory neurons, a critical indicator of translational potential. A companion study in Nature revealed the molecular architecture behind the mechanism, showing exactly how the compound physically redirects which proteins the receptor activates. That structural insight opens possibilities not just for pain medicine but for drug design across an entire family of receptors.
Led by Steven Olson at Sanford Burnham Prebys, with co-investigators Ru-Rong Ji at Duke and Lauren Slosky at Minnesota, the team will use computational design and machine learning to optimize the compound over the next two years, targeting a remaining cardiac safety concern and examining whether the drug behaves differently across sexes. If development milestones are met, the NIH has indicated it will award an additional $4 million to complete preclinical work and launch a Phase 1 safety trial in healthy volunteers — potentially placing a new class of pain medicine within reach of the millions of Americans for whom current options remain inadequate or dangerous.
The National Institute of Neurological Disorders and Stroke has committed $3.9 million to a research team working on a fundamentally different approach to pain relief—one that sidesteps the addiction and overdose risks that have made opioids so dangerous. The money, awarded under the NIH's Healing to End Addiction Long-term initiative, goes to scientists at Sanford Burnham Prebys Medical Discovery Institute, Duke University, and the University of Minnesota to refine a molecule called SBI-810 and move it toward human testing.
The scale of the problem they're trying to solve is enormous. Roughly 80 percent of the 19 million Americans who have major surgery each year wake up in significant pain. Another 25 million live with chronic pain that never fully resolves. Current treatments—opioids chief among them—often fail to control that pain adequately while introducing their own catastrophic risks. The researchers leading this effort see an opening in a receptor in the brain and nervous system called neurotensin receptor 1, or NTR1. Decades ago, scientists discovered that the natural molecule activating this receptor produced pain relief more powerful than morphine. The problem was that drugs targeting NTR1 directly caused dangerous side effects: sudden drops in blood pressure and body temperature that made them too risky to use.
SBI-810 takes a different path. Instead of binding to the main active site on the receptor—the approach most drugs use—it slips into a hidden pocket on the receptor's interior. This allows it to act as what researchers call a biased allosteric modulator, selectively activating one beneficial signaling pathway while blocking the pain-promoting ones. The result, according to recent studies, is potent pain relief without the blood pressure crashes and temperature drops that derailed earlier attempts. The compound also showed promise in reducing opioid-related side effects like constipation and withdrawal symptoms, suggesting it could work alongside existing pain management rather than replacing it entirely.
The scientific foundation for this work is unusually solid. A 2025 study published in Cell demonstrated that SBI-810 produced strong pain-relieving effects across multiple animal models—postoperative pain, inflammatory pain, neuropathic pain. Critically, it worked through both peripheral and central nervous system mechanisms and suppressed pain signaling in human sensory neurons, a crucial indicator that the findings might actually translate to people. A second 2025 study in Nature revealed the molecular architecture explaining how this class of compounds works, showing exactly how SBI-810 binds at the interface between the receptor and its signaling partners, physically redirecting which proteins the receptor activates. That structural insight opens a door not just for pain drugs but for an entirely new way of designing medicines across a vast family of receptors.
The grant is structured to move efficiently from lab to clinic. Over the next two years, the team—led by Steven Olson at Sanford Burnham Prebys, with co-investigators Ru-Rong Ji at Duke and Lauren Slosky at Minnesota—will use computational design and machine learning to optimize the compound, focusing on maximizing pain relief while eliminating a remaining cardiac safety concern. They'll test candidates in mouse and rat models, paying careful attention to whether the drug works differently in males and females. If they hit their milestones, the NIH has signaled it will award an additional $4 million to complete preclinical work and run a Phase 1 safety trial in healthy volunteers.
What makes this effort distinctive is the collaboration itself. The team brings together medicinal chemists, structural biologists who understand how proteins fold and function, pain neuroscientists, and pharmacologists who study how drugs behave in living systems. That combination of expertise, spread across three institutions, is precisely what the HEAL Initiative was designed to support. The researchers are explicit about what they're aiming for: a new medicine for the millions of Americans whose pain remains inadequately treated and who face the constant threat of addiction if they turn to opioids. If the science holds and the regulatory path clears, a Phase 1 trial could begin within two years.
Citações Notáveis
Neurotensin, the natural molecule that activates NTR1, was shown decades ago to produce pain relief more potent than morphine. The challenge has been harnessing that power without the side effects.— Ru-Rong Ji, Distinguished Professor of Anesthesiology at Duke University
Understanding how these compounds change receptor behavior at a molecular level is a gamechanger. It means we can design better drugs with greater precision, rather than relying on trial and error.— Lauren M. Slosky, assistant professor at the University of Minnesota
A Conversa do Hearth Outra perspectiva sobre a história
Why does this particular receptor matter so much? There must be hundreds of targets in the brain.
Neurotensin receptor 1 has a unique history. Scientists found decades ago that its natural activator—neurotensin itself—produced pain relief stronger than morphine. But every drug that tried to harness that power caused dangerous side effects. This team figured out how to get the benefit without the harm.
How did they solve a problem that's stumped researchers for decades?
They stopped trying to hit the main active site on the receptor. Instead, they found a hidden pocket on the inside and designed a molecule that binds there. It's like finding a back door to the same room.
And that back door only opens the good pathways?
Exactly. It activates one specific signaling protein—beta-arrestin-2—while blocking the pain-promoting G protein pathways. The side effects came from activating both at once.
The studies in Cell and Nature—those are major journals. What did they actually show?
The Cell paper proved the compound works across multiple pain models in animals and even suppresses pain signaling in human nerve cells. The Nature paper revealed the molecular blueprint—how the compound physically redirects which proteins the receptor talks to. That's the kind of insight that could reshape how we design drugs across an entire family of receptors.
So this isn't just about pain relief. It's about a new way of making drugs.
That's the real breakthrough. Understanding the architecture at the molecular level means you can design with precision instead of trial and error. It applies to hundreds of other receptors throughout the body.
What happens if the milestones aren't met?
Then the research stops. But the team has two years and $3.9 million to optimize the compound and prove it's safe enough to test in humans. If they succeed, another $4 million comes through for the final preclinical work and the first human trial.