About the Study

Pain is a major problem in many people with advanced cancer. Despite improvements in pain medication, pain medication delivery systems, and physician awareness, some people with cancer continue to have severe and debilitating pain. This pain often impairs their ability to function and diminishes their quality of life. Although narcotics can be very effective in the treatment of pain, they can have troublesome side effects, such as nausea, vomiting, sedation, constipation, and hallucinations. In some cases, people take low doses of their pain medication and live with pain to avoid the side effects. We and other researchers are looking for better pain treatments for people living with cancer.

This study is a Phase I clinical trial to test the safety and effectiveness of a new treatment for unmanageable pain in people with advanced cancer. Phase I trials are the very first stage of testing a medication in people. The drug being tested is called resiniferatoxin or RTX. RTX is extracted from a North African plant. RTX is similar to capsaicin, the active ingredient in hot peppers but much stronger. Capsaicin is used for the treatment of pain when placed on the skin surface. RTX has been used previously to treat pain. In ancient times, it was used on the skin or gums to treat arthritis and dental pain. More recently, RTX has been injected into the bladder for studies on the treatment of overactive bladder.

In this study, RTX will be injected directly into the spinal fluid surrounding the spinal cord through a spinal tap. This study will be the first time RTX is injected directly into the spinal fluid. The FDA has not approved RTX for the treatment of unmanageable pain in people with advanced cancer, but has given permission for its use in this study as an “investigational new drug.”

Research on animals has shown that injecting RTX into the spinal fluid can relieve pain. RTX works by permanently destroying pain-sensing nerves. In animals, RTX did not affect other nerves that control muscle movements or that detect sensation.

Each participant in this study will receive a single dose of RTX. The first 3 to 6 participants will be given extremely low doses of RTX to help us evaluate the safety of the drug given into the spinal fluid. The dose of RTX will be gradually increased in subsequent groups of people to find out more about its safety and effectiveness in treating severe cancer pain.

More information about this study may be found at ClinicalTrials.gov.