Scientists at the U.S. National Institutes of Health (NIH) have developed a groundbreaking therapy for patients suffering from severe, treatment-resistant cancer pain. Derived from Euphorbia resinifera, a cactus-like plant native to North Africa, the molecule resiniferatoxin (RTX) has shown extraordinary promise in early human trials.
In the study, patients with end-stage cancer who had not found relief from even the strongest opioid treatments received a single injection of RTX into the spinal fluid. The results were striking: a 38% reduction in worst pain intensity and a 57% drop in opioid use. Even more encouraging, patients reported being able to reconnect with daily life and loved ones, no longer dependent on heavy sedation.
Unlike opioids, RTX is non-addictive and works by selectively targeting and deactivating pain-transmitting nerve fibers, without affecting other sensations like touch or movement. This precision makes RTX a revolutionary tool in pain management, particularly for cancer-related suffering.
Dr. Andrew Mannes, lead author of the study, at National Institute of Health, called the treatment “a new therapy from a new family of drugs” with the potential to restore quality of life. Senior scientist Dr. Michael Iadarola explained that RTX essentially “cuts the pain-specific wires,” offering targeted relief while preserving overall nerve function.
The implications extend beyond cancer. RTX could eventually help treat other chronic pain conditions, including nerve injuries and facial pain disorders.
As larger trials are planned to confirm the safety and effectiveness of RTX, this discovery marks a major step forward in personalized, non-addictive pain treatment.
Reference:
Mannes, A., Iadarola, M. et al. Treatment of Intractable Cancer Pain with Resiniferatoxin — An Interim Study. NEJM Evidence. 2025. DOI: 10.1056/EVIDoa2400423
Serra Húnter Fellow of Sociology at Universitat Rovira i Virgili.
Former DAAD-Gastprofessorin at Julius-Maximilians-Universität Würzburg