Teriflunomide in HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis

Background: HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a rare, progressive disease. It occurs in some people infected with the HTLV-1 virus. It leads to weakness in the lower limbs and other serious problems. It has no treatment. Teriflunomide is a drug used to treat multiple sclerosis. It reduces immune cells that make the disease worse. Researchers want to learn if this drug can help people with HAM/TSP. Objective: To learn the effects, immune response, safety, and tolerability of teriflunomide in people with HAM/TSP. Eligibility: Adults ages 18 and older with HAM/TSP. Design: Participants will be screened under protocol 98-N-0047. Participants will have a medical history. They will have physical and neurological exams. They will have blood and urine tests. Participants will take 1 tablet of the study drug once a day for 9 months. They will keep a drug diary. Participants will have lymphapheresis. For this, blood is drawn from a needle in one arm. A machine divides the blood into red cells, plasma, and white cells. The white cells are removed. The plasma and red cells are returned to the participant through a needle in the other arm. Participants will have lumbar punctures ( spinal taps ). For this, a thin needle is inserted into the spinal canal in the lower back. Spinal fluid is removed. Participants will have magnetic resonance imaging (MRI) of the brain and spine. The MRI scanner is a metal cylinder surrounded by a strong magnetic field. During the MRI, participants will lie on a table that can slide in and out of the scanner. Participation will last for 15 months.

Study Description: In this single center, single arm, open label, baseline versus treatment pilot clinical trial, sixteen subjects with HAM/TSP will receive teriflunomide 14mg by mouth once a day in an initial 9 month treatment phase, followed by a 3 month post treatment follow-up phase. Outcome measures will be collected every 3 months for the duration of the study. Objectives: We will determine the effects of teriflunomide, an FDA approved drug for the treatment of relapsing remitting multiple sclerosis that inhibits de novo pyrimidine synthesis, on immune activation markers in patients with HAM/TSP and the correlation of these with virological, radiological and clinical measures of disease burden . Endpoints: The primary outcome measure is ex vivo spontaneous lymphoproliferation in HAM/TSP patients receiving teriflunomide. Secondary outcome measures will include determination of immune activation patterns of PBMC and CSF using multicolor flow cytometric analysis and HTLV-I proviral load in blood and CSF. Safety and tolerability of teriflunomide will be assessed by tabulation of adverse events, clinical exam, standardized neurological disability scales (EDSS, IPEC, HAQ-DI), MR imaging of brain and spinal cord and clinical laboratory studies.