Open Access Research article

Efficacy of prosultiamine treatment in patients with human T lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis: results from an open-label clinical trial

Tatsufumi Nakamura1*, Tomohiro Matsuo2, Taku Fukuda3, Shinji Yamato1, Kentaro Yamaguchi4, Ikuo Kinoshita5, Toshio Matsuzaki6, Yoshihiro Nishiura7, Kunihiko Nagasato7, Tomoko Narita-Masuda3, Hideki Nakamura3, Katsuya Satoh1, Hitoshi Sasaki4, Hideki Sakai2 and Atsushi Kawakami3

Author Affiliations

1 Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan

2 Department of Nephro-Urology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan

3 Translational Medicine Unit, Department of Clinical Neuroscience and Neurology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan

4 Department of Hospital Pharmacy, Nagasaki University Hospital, Nagasaki, Japan

5 Neurology Section, Japanese Red Cross Nagasaki Genbaku Hospital, Nagasaki, Japan

6 Department of Neurology, Okatsu Hospital, Kagoshima, Japan

7 Neurology Section, Isahaya Health Insurance General Hospital, Nagasaki, Japan

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BMC Medicine 2013, 11:182  doi:10.1186/1741-7015-11-182

Published: 15 August 2013



Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic myelopathy characterized by motor dysfunction of the lower extremities and urinary disturbance. Immunomodulatory treatments are the main strategy for HAM/TSP, but several issues are associated with long-term treatment. We conducted a clinical trial with prosultiamine (which has apoptotic activity against HTLV-I-infected cells) as a novel therapy in HAM/TSP patients.


We enrolled 24 HAM/TSP patients in this open-label clinical trial. Prosultiamine (300 mg, orally) was administered once daily for 12 weeks. We monitored changes in the motor function of the lower extremities and urinary function as well as copy numbers of the HTLV-I provirus in peripheral blood mononuclear cells (PBMCs).


Improvement in the motor function of the lower extremities based on a reduction in spasticity (for example, decrease in time required for walking and descending a flight of stairs) was observed. In an urodynamic study (UDS), bladder capacity and detrusor pressure and then maximum flow rate increased significantly. Detrusor overactivity and detrusor-sphincter dyssynergia improved in 68.8% and 45.5% of patients observed at pretreatment, respectively. Improvement in UDS corresponded with improvements in the score of nocturia-quality of life questionnaire. HTLV-I proviral copy numbers in PBMCs decreased significantly (approximately 15.4%) compared with pretreatment levels.


These data suggest that prosultiamine can safely improve motor dysfunction of the lower extremities and urinary disturbance as well as reduce HTLV-I provirus levels in peripheral blood. It therefore has potential as a new therapeutic tool for HAM/TSP patients.

Trial registration

University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) number, UMIN000005969.

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HAM/TSP; HTLV-I; Prosultiamine; Treatment