A Phase 1 Study of Substance P-Saporin in Terminal Cancer Patients With Intractable Pain

Screening (-7 days to Day 0) * Physical exam and medical history; * Vital signs; * Blood tests; * Pain measurements (6 daily pain questionnaires for 7 days prior to receiving study drug); * Urine tests; * Pregnancy test; * Electrocardiogram (EKG), a tracing of the electrical activity of the heart; * Collection of demographic information (age, sex, ethnic origin); Study Drug: SP-SAP will be administered via a spinal injection. Depending on when the subject is enrolled in the study, the dose of SP-SAP will be between 1 and 90 micrograms of SP-SAP Therapy: Subject will arrive at the UTSW Eugene McDermott Center for Pain Management 2 hours prior to treatment. The following will take place: * Physical exam; * Pain measurements (6 pain questionnaires); * EKG; * The subject will have a catheter inserted into their spine and will receive the study drug intrathecally (into their spine). The catheter will remain in their spine for 4 hours. Less than 1 tablespoon of spinal fluid will be collected for research purposes; and * They will remain in the University of Texas Southwestern Medical Center Hospital for 24 hours for observation as a precaution. Follow-Up will occur weekly for 8 weeks and then monthly for 4 months as needed. During these visits the following will take place: * Physical exam (including sensory and motor skills) and medical history; * Vital signs; * Two tablespoons of blood will be drawn from your arm by needle stick for blood tests; * Pain measurements (6 pain questionnaires); * Urine tests; and * Electrocardiogram (EKG), a tracing of the electrical activity of the heart. The subject will be asked to keep a diary to record any nausea and vomiting as well as a medication log to record the pain medications and dosage that they take between visits. Each visit will take approximately 2 hours to complete 4 Month Follow-Up Informational data on the level of pain, adverse events, and sensory and motor function will be collected for the remaining 4 months of the study or until time of death. This information may be collected via patient diary, office visit or telephone interview.