Resiniferatoxin to Treat Severe Pain Associated With Advanced Cancer

This study will examine the safety of giving the experimental drug, resiniferatoxin (RTX), to treat severe pain in patients with advanced cancer. RTX is a chemical extracted from a cactus-like plant. It is similar to capsaicin, the active ingredient in hot pepper. RTX has relieved pain and reduced the need for pain medication in several animal experiments. It works by destroying nerves that transmit pain information. People at least 18 years of age with severe pain from advanced cancer at or below the level of the chest that cannot be controlled with standard treatments may be eligible for this study. Participants undergo the following procedures: Pretreatment Visit Before beginning treatment with RTX, patients give a medical history and undergo a physical examination that includes: * Electrocardiogram (EKG) * Blood draw * Urinalysis * Neurological examinations * Peak expiratory flow rate (PEFR) * Eye examination * MRI * Urology assessment * Pregnancy test, when appropriate * Questionnaires to collect information on health, personality, mood, pain levels and symptoms. 2-Day Hospitalization Patients are hospitalized for 2 days for RTX injection and monitoring, as follows: * RTX injection: RTX is injected in the operating room under general anesthesia. It is given through a catheter placed in the patient s spine. The catheter is also used to obtain samples of cerebrospinal fluid (CSF) the clear fluid that bathes the spinal cord. The fluid is examined to assess drug effects and side effects, chemical changes in the content of the CSF associated with RTX, and how RTX is handled by the body. * Post-injection monitoring, including: * Surveys about symptoms such as pain or weakness * Neurological examinations * Blood and CSF sampling * EKG * AEs Outpatient followup * Vitals * Blood draw, Urinalysis, neurological and sensory testing, EKG on days 7, 14 and 30 after the injection * MRI scans of the head and back, Urology assessment and PEFR on day 15 after the injection * Eye examination * Follow-up phone calls monthly for 6 months