Fentanyl Citrate

A new experimental vaccine developed by Scripps Research could offer a powerful new way to prevent fentanyl overdoses by stopping the drug before it reaches the brain. Rather than targeting only fentanyl itself, the vaccine trains the immune system to recognize a broad range of fentanyl-related designer drugs, including some of the most dangerous variants.Fentanyl has become one of the deadliest drugs in the United States. Each year, fentanyl and related synthetic opioids are responsible for more deaths than car crashes and gun violence combined. In high doses, these drugs disrupt normal brain function and can suppress the signals that control breathing, often leading to fatal overdoses. Although medications can reverse an overdose, they must be administered quickly to be effective. Researchers at Scripps Research are now exploring a very different strategy. Instead of treating an overdose after it happens, they have developed an experimental vaccine designed to stop fentanyl from reaching the brain in the first place. The findings, published in the Journal of Medicinal Chemistry, indicate that the vaccine may provide protection not only against fentanyl itself but also against a wide range of fentanyl-related "designer drugs." These modified versions are often created to increase potency or help manufacturers avoid detection and regulation. "What this research shows us is that we don't have to keep playing catch-up with every new synthetic designer drug that emerges," says senior author Kim Janda, the Ely R. Callaway, Jr. Professor of Chemistry at Scripps Research. "By training the immune system to recognize the entire fentanyl class -- not just individual structures -- we can stay ahead of illicit drug traffickers." A New Approach to Fentanyl Prevention Scientists have spent years working on vaccines that trigger the production of antibodies capable of binding to fentanyl in the bloodstream before it can affect the brain. Janda's laboratory has previously developed vaccine candidates targeting both fentanyl and heroin. However, most vaccine designs rely on the drug itself, or a molecule that closely resembles it, to train the immune system. That approach presents two major challenges. First, the drugs involved are highly regulated, making research and development more difficult. Second, the immune response tends to be highly specific, meaning it may recognize only the exact drug used in the vaccine. "The way the fentanyl landscape is evolving, the black-market drug makers are constantly coming up with new versions to skirt regulations and avoid detection in standard screenings," says Janda. "We need countermeasures that are going to work against all these future variants at once, not just one at a time." Testing an Unconventional Vaccine Design In earlier research, Janda's team developed a modified form of fentanyl that maintained its pain-relieving effects while eliminating many of the drug's harmful side effects. For the new study, the researchers investigated whether a related molecule could serve as the foundation for a vaccine. The molecule shared some characteristics with fentanyl but had a fundamentally different core structure. "When we started testing this molecule as a vaccine component, we honestly didn't know if it would work," says Arran Stewart, a research associate in the Janda lab and first author of the study. "The conventional wisdom says that to get the immune system to recognize fentanyl, you have to use something that looks like fentanyl. We were doing the opposite." To test the idea, the team attached the modified molecule to a carrier protein and administered four vaccine doses to mice over an eight-week period. The results surprised the researchers. Rather than requiring an exact match to fentanyl's structure, the immune system generated antibodies that recognized a broader molecular signature shared by many fentanyl-related compounds. Broad Protection Against Fentanyl Variants When the scientists evaluated the antibodies against multiple fentanyl designer drugs, the vaccine demonstrated the broad protection they had hoped to achieve. The antibodies strongly recognized fentanyl as well as several dangerous variants, including carfentanil, China White, acetylfentanyl and furanylfentanyl. At the same time, they did not bind to commonly used medical opioids such as morphine, oxycodone, remifentanil and alfentanil. The protective effects were also evident in animal testing. Mice that received the vaccine maintained nearly normal breathing even after being given fentanyl doses that would typically cause severe respiratory depression. Researchers also found that fentanyl levels in the brains of vaccinated mice were approximately 70% lower than in mice that had not received the vaccine. Potential Future Applications The vaccine must still undergo clinical trials to determine whether it is safe and effective in people. Even so, Janda believes the platform could eventually help protect individuals enrolled in substance abuse recovery programs and others who face a high risk of fentanyl exposure. "The public health potential here is significant," says Janda. "But so is the lesson that we can design vaccines that recognize an entire drug class, not just a singular drug." The study, titled "Redefining Drug Immune Recognition: A Radically Reconfigured Molecular Architecture Enables Broad Fentanyl-Class Protection," was authored by Janda, Stewart, Lisa Eubanks, Bin Zhou and Rachel Steinhardt, all of Scripps Research. The work was supported by the Shadek Family Foundation.

Interim phase 1/2 data confirm significant anti-fentanyl antibody production at the lowest dose, with a well-tolerated safety profile across all patients dosed. NEW YORK, June 17, 2026 /PRNewswire/ -- ARMR Sciences, a clinical-stage biodefense company developing a platform of medical countermeasures against synthetic drugs, such as fentanyl, today announced that its lead product, ARMR-100, has generated an anti-fentanyl immune response against fentanyl in humans while showing favorable safety data. The result demonstrates that the formulation can produce an immune response in humans and marks a critical milestone in the company's path toward demonstrating that this response can protect against fentanyl. ARMR-100 is being designed to work with the body to generate a protective immune response. The product, in a Phase 1/2 clinical trial, is being developed to generate an immune response that produces anti-fentanyl antibodies capable of binding to lethal synthetic drugs. Once the antibodies bind to the synthetic drug target, such as fentanyl, the drug is prevented from entering the brain. If the molecule is prevented from reaching the brain, then the downstream effects that lead to overdose may also be prevented. ARMR-100 is in development to be the first long-lasting preventive medication against fentanyl, with the goal that the product endures for 6-12 months in healthy adults. The next phase is evaluating protection against fentanyl, currently on track to begin in Q3 2026. "The antibody response we observed at the lowest dose level tested has been robust, with anti-fentanyl IgG titers well above pre-vaccination baseline. These early immunogenicity data are encouraging as we advance to higher dose cohorts and, ultimately, to the human fentanyl challenge phase of the study," said Dr. Seth Toback, Chief Medical Officer of ARMR Sciences. Fentanyl, a lethal killer, is responsible for approximately 100+ American deaths per day1. According to the latest CDC data, overdose has become the leading cause of death for Americans aged 18 to 45, driven primarily by fentanyl and other synthetic drugs2. Over the last 10 years, more than 450,000 lives have been lost to the drug3. This exceeds the total amount of U.S. combat deaths in WWII. ARMR believes that the data represent a foundational milestone in its development program. Establishing that the vaccine can elicit an immune response in humans is the prerequisite for the company's central thesis: that vaccine-induced antibodies can intercept fentanyl before it reaches the brain. With evidence of human immunogenicity now demonstrated, ARMR expects to advance to the next phase of its clinical trial, designed to evaluate the protective efficacy of this immune response against fentanyl, which is expected to begin in August. "We are turning what many called impossible into reality," said Collin Gage, CEO of ARMR Sciences. "These positive early results are a testament to the deeply experienced team of scientists, researchers, and medical professionals we have assembled. While there is still important work ahead, we believe today's milestone further validates our approach and reinforces our confidence in the path forward as we continue advancing a potential solution that could save countless lives." ARMR-100 has been well tolerated across the first three patient cohorts, comprising 24 patients in total. Enrollment began in March 2026, and to date, three groups of eight participants have been dosed. The study Safety Committee has reviewed the data at multiple points and has authorized the trial to advance to higher dose levels. No serious medical events have been observed. Reported adverse events have been minor, infrequent, and short-lived, consisting primarily of occasional headaches and consistent with the typical response to other inoculations. The safety profile observed to date supports the candidate's continued advancement to higher-dose cohorts and the next phase of clinical evaluation. ARMR-100 generated this immune response at the lowest dose of this escalation study, representing the floor of the program's dosing range. Even at this dose, early participants have shown a meaningful increase in anti-fentanyl antibodies following vaccination, meeting the requirements to enter the planned fentanyl challenge phase of the study. Achieving a strong human immune response at the lowest dose is an encouraging signal as the company moves toward testing protective efficacy. The forthcoming phase will assess, in humans, the degree of protection conferred by this immune response against fentanyl. "Seeing this immune response in human subjects demonstrates a critical translation of the seminal work by Professor Colin Haile and his team in the discovery of ARMR-100," said Dr. Nick Jacob, chief scientific officer of ARMR Sciences. In rodent models, ARMR-100 produced robust protection, preventing an estimated 90% to 100% of fentanyl from reaching the brain and eliminating its downstream behavioral effects that may lead to addiction. ARMR-100 has previously shown in preclinical research that it does not cross-react with critical pain medications currently used in emergency room settings and post-operative care. This selectivity means that important analgesic medications can still be used to manage pain in an emergency. Additionally, in preclinical models, ARMR-100 has been shown to work alongside currently available reactive overdose treatments, such as naloxone. ARMR-100 employs a natural, protein-based, heavy metal-free formulation that does not contain aluminum, thimerosal, mercury, or other heavy metal-based additives. This formulation approach is a core feature of the candidate's profile as the program advances. About ARMR Sciences ARMR Sciences is a clinical-stage biodefense company developing a platform of medical countermeasures against synthetic drugs, including fentanyl, and other emerging chemical threats. The company's lead product, ARMR-100, is designed to generate a protective immune response that produces antibodies capable of binding synthetic molecules and blocking them from reaching the brain. For more information, visit Forward-Looking Statements This press release contains forward-looking statements within the meaning of applicable securities laws, including statements regarding the anticipated timing and design of ARMR Sciences' clinical trials, the potential of ARMR-100 to generate a protective immune response and to protect against fentanyl overdose, the targeted duration of that protective response, its selectivity relative to therapeutic pain medications, its compatibility with existing overdose rescue treatments, and the company's development plans. These statements are based on current expectations and are subject to risks and uncertainties that could cause actual results to differ materially, including risks related to the conduct, timing, and results of clinical trials; the unpredictability of preclinical and clinical data; regulatory review and approval; and the company's ability to obtain financing. Preclinical results, including the protection, selectivity, and compatibility observed in animal studies, are not necessarily predictive of results in humans. ARMR Sciences undertakes no obligation to update any forward-looking statement except as required by law. Investor and Media Contact Andy Dueñas [email protected] SOURCE ARMR Sciences Inc. 21% more press release views with Request a Demo