Cessation Therapeutics’ Anti-Fentanyl Monoclonal Antibody Treatment Shows Promise in Protecting Against Fentanyl-Induced Overdose

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Single administration of treatment blocked life-threatening, fentanyl-induced respiratory depression in non-human primates for at least 3 weeks

CHAPEL HILL, N.C.--(BUSINESS WIRE)--Cessation Therapeutics (“Cessation”), an early-stage biotechnology company focused on the development of novel immunobiologics for preventing and treating fentanyl overdose, today announced a new study demonstrating that its pioneering anti-fentanyl monoclonal antibody treatment, CSX-1004, may provide robust and durable protection from life-threatening respiratory depression caused by high doses of fentanyl.

The findings come from the company’s ongoing series of proof-of-concept studies in non-human primates. Funded in part by a grant (U01DA051071) from the National Institute on Drug Abuse (NIDA) at the National Institutes of Health (NIH) through the Helping to End Addiction Long-term Initiative (NIH HEAL Initiative), the studies are designed to assess the antibody’s ability to block the respiratory depressant effect of fentanyl, the attribute of the drug that is ultimately the cause of death in an overdose scenario.

Researchers led by Dr. Paul Bremer, Cessation’s Director of Research and Development, and Dr. Rajeev Desai, Assistant Professor of Psychiatry at Harvard Medical School and Director of the Integrative Neurochemistry Laboratory at McClean Hospital, found that a single infusion of CSX-1004 created an effective blockade against the potentially toxic effects of fentanyl on the respiratory system of non-human primates for more than three weeks.

“The results from this study are extraordinary and come at a critical time as overdose from synthetic opioids, primarily fentanyl, is the leading cause of death for Americans ages 18 to 45,” said Cessation Chief Scientific Officer, Andy Barrett, PhD. “Over 70,000 Americans died from fentanyl-related overdose in 2021 – that’s like having a 737 commercial airliner crash every single day. This treatment, with the potential to protect individuals from the toxic effects of fentanyl, offers real hope to patients suffering from opioid use disorder (OUD) and their families.”

CSX-1004 works by targeting fentanyl molecules as they enter the bloodstream, effectively sponging them up in the blood before they reach the brain. The Cessation treatment does not enter or bind to receptors in the brain, thereby avoiding the risk of addiction.

Importantly, the Harvard University and McLean Hospital study further found that CSX-1004 blocked the respiratory effects of fentanyl without impacting the efficacy of other opioid medications. This means that patients could be protected from fentanyl overdose and still have access to other medications that provide essential pain relief or anesthesia for surgery. This specificity for fentanyl also provides the possibility for this treatment to effectively bridge patients to other critical medications for opioid use disorder (MOUDs), offering overdose protection while supporting and enhancing long-term recovery.

Cessation has also conducted a battery of nonclinical safety tests and established a reliable manufacturing process for the antibody, work necessary to enable Cessation to file a full Investigational New Drug (IND) application with the U.S. Food and Drug Administration (FDA), something the company plans to do in April 2023.

If approved, Cessation’s antibody treatment would be the first marketed product designed for the prevention of fentanyl overdose.

“Cessation is a company with big ideas around hard problems,” said Cessation CEO, Tracy Woody. “Fentanyl overdose is killing thousands of Americans every month, and there are currently no FDA-approved products specifically designed to prevent it. Cessation’s anti-fentanyl monoclonal antibody treatment represents a meaningful breakthrough, and we look forward to working with the FDA and other government agencies on the next steps for this potentially life-saving treatment.”

Research reported in this press release was supported by the National Institute on Drug Abuse of the National Institutes of Health under award number U01DA051071. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

About Cessation: Cessation Therapeutics is an early-stage pharmaceutical company working to develop novel immunobiologics designed to prevent and protect against overdose. With an initial focus on fentanyl, Cessation’s monoclonal antibodies can be adapted to target future synthetic opioids and other substances. Cessation has the potential to treat a range of substance use disorders and improve the lives of patients and families affected by the addiction crisis. For more information on Cessation, please visit

The Helping to End Addiction Long-term® Initiative, or NIH HEAL Initiative®, is an aggressive, trans-NIH effort to speed scientific solutions to stem the national opioid public health crisis. Launched in April 2018, the initiative is focused on improving prevention and treatment strategies for opioid misuse and addiction, and enhancing pain management. For more information, visit:


Caitlin Sickles 202-828-7637

Caitlin Sickles 202-828-7637