This is a pilot study of intervention in a group of patients with tropical spastic paraparesis/ myelopathy to evaluate virologic and clinical response of raltegravir plus zidovudine in this group of patients.

The study will the investigators develop in The Tropical Medicine Institute Alexander von Humboldt that is a referral center in Peru for diseases associated to Human T-Lymphotropic Virus 1 Infection (HTLV-1). The Institute has a cohort of around 600 patients currently being followed up and around 20 to 25 new patients are admitted every year with this disease.

This is a pilot study of intervention in a group of patients with tropical spastic paraparesis/ myelopathy to evaluate virologic and clinical response of raltegravir plus zidovudine in this group of patients on the follow-up of 48 weeks.

Inclusion Criteria:

• human t lymphotrophic virus 1 confirmed
• Tropical Spastic Paraparesis of recent onset (less than 4 years)

Exclusion Criteria:

• Pregnant or breastfeeding or unwilling to use contraception.
• Treatment with immunosuppressive, immunomodulatory or experimental treatments within the last 6 months of enrolment in the study.
• Patients presenting with medical disorder such as poorly controlled diabetes or arterial hypertension, severe cardiac insufficiency, unstable ischemic heart disease, abnormal liver function tests (>2.5 times upper limit normal (ULN)) and abnormal complete blood count (in particular leukopenia, as defined by a lymphocyte count <500, neutrophil <1.5 or platelet count < 100, or thrombocytopenia < 1.5 low limit normal (LLN), or any medical condition which, in the opinion of the chief investigator, would pose additional risk to the patient.
• Presence of human immunodeficiency virus antibodies.
• Patients with active hepatitis B or/and C with liver function tests >2.5 times ULN
• Exposure to any other investigational drug within 30 days of enrolment in the study.