A Phase 2 interventional study of Combination of Dolutegravir + Tenofovir DF for treatment of HTLV-1 infection and Dolutegravir (DTG) in HTLV-1 Infection, HTLV I Associated Myelopathies and HTLV I Associated T Cell Leukemia Lymphoma, sponsored by Carlos Brites. Recruiting at 1 site in Brazil. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-02.
Sponsored by Carlos Brites · Phase 2, Interventional, and Treatment
This phase 2b, open-label, randomized controlled trial evaluates the efficacy and safety of dolutegravir (DTG) alone versus dolutegravir combined with tenofovir disoproxil fumarate (TDF) in individuals with HTLV-1 infection and associated clinical manifestations. The primary objective is to compare changes in HTLV-1 proviral load at 24 and 48 weeks. Secondary outcomes include clinical, functional, immunological, and quality-of-life measures.
Human T-lymphotropic virus type 1 (HTLV-1) infection is a neglected condition associated with severe neurological and hematological diseases, including HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Currently, no effective antiviral therapy exists.
Preclinical and clinical data suggest that integrase inhibitors such as dolutegravir may reduce HTLV-1 proviral load. Additionally, combination therapy with tenofovir may enhance antiviral activity. This study builds on prior pilot data demonstrating partial virological response to DTG.
Participants will be randomized (1:1) to receive DTG alone or DTG plus TDF for 48 weeks. Outcomes will include virological, immunological, clinical, and patient-reported measures. The study aims to provide evidence for therapeutic strategies targeting HTLV-1.
23 studies on the registry are indexed under Paraparesis, Tropical Spastic; 2 are open to participants now.
This study's planned enrollment of 146 is above the median of 19 across 18 interventional studies indexed under Paraparesis, Tropical Spastic.
Browse Paraparesis, Tropical Spastic studies →This is the only study on the registry with Carlos Brites as lead sponsor.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Dolutegravir 50 mg p.o. daily
Drug: Dolutegravir (DTG)
Daily Dolutegravir 50 mg Daily Tenofovir 300 mg
Combination Product: Combination of Dolutegravir + Tenofovir DF for treatment of HTLV-1 infection
In a previous study Dolutegravir was able to reduce HTLV-1 proviral load, but a few patients did not respond to therapy. We intend to use a combination of Dolutegravir + TDF to improve the response rate. There is no previous evidence on the use of such combination for treating HTLV-1 infection.
Active comparator will be DTG, 50 mg/day
HTLV-1 Proviral Load
Measurement of HTLV-1 Proviral Load by RT-PCR. Results will be expressed as copies/ml of whole blood
Time frame: From baseline to the end of treatment at 48 weeks
Changes in Pain intensity (DN4 doleur scale)
Change in intensity of pain measured by DN4 doleur scale (0 to 10, with values \>4 indicating neuropathic pain)
Time frame: Baeline, 24 and 48 weeks
Changes in Spasticity
Changes in limbs spasticity, as measured by Ashworth scale. The Ashworth Scale uses a simple ordinal scale ranging from 0 to 4, where the highest values mean increased spasticity
Time frame: BL, 24 and 48 weeks
Changes in muscle strenght
Evaluation of muscle strenght by Kendall Muscle Grading system (Kendal scale), which ranges from 0 to 10, with highest values indicating better muscle strenght
Time frame: BL, 24 and 48 weeks
Changes in motor score scales
Evaluation of changes in motor performance using the lower extremity motor score (LEMS) is a subscale of the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) that assesses lower extremity muscle strength.The score range is 0-5 for each of 5 key muscles (hip flexors, knee extensors, ankle dorsi-flexors, long toe extensors and ankle plantar flexors) of each leg, with a maximum score of 50 (the lower values indicates worse motor function)
Time frame: BL, 24, 48 weeks
Nocturia frequency
Nocturia frequency across the study
Time frame: Baseline, 24 and 48 weeks
Cytokines levels
Measurement of levels of (Tumon Necrosis Factor-Alpha) TNF-alpha, IL-6, IL-2, IL-4, IL-10, Interferon γ-induced Protein (IP-10), Gamma-Interferon (Gamma-IFN), in picogram/cubic milimiter. Values may varies from undetectable levels to any detectable concentration, expressed in pg/mm3.
Time frame: BL, 24 and 48 weeks
RAND 36-Item Health Survey
The RAND Corporation Health-Related Quality of Life (RAND-36) domains are scored on a 0 to 100 range, so that a high score defines a more favorable health-related quality of life (HRQoL). The scale measure several domains of HRQoL.
Time frame: Baseline and at 48 weeks
Quantification of HTLV-1
To evaluate active replication of HTLV-1, we will measure the number of copies of Long Terminal Repeat (LTR) circles to detect HTLV-1 unintegrated proviral genome and HTLV-1 plasma RNA levels. Presence of any number of copies of LTR indicates ongoing active viral replication
Time frame: BL, at 24 and 48 weeks
Frequency of Adverse events and Serious adverse events
frequency of incident AE associated with the treatment drugs
Time frame: baseline to 48 weeks
Measurement of Levels of sCD14 and sCD163
Levels of soluble cluster of diferentiation 14 (sCD14) and 163 (sCD14), expressed in ng/mL, will be measured to evaluate levels of monocytes´ activation across the trial. Higher levels indicate increased monocytes´ activation.
Time frame: BL, 24 and 48 weeks
Plan to share: Yes — Anonimized clinical data can be shared with other researchers upon reasonable request
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report, Analytic code
Time frame: IPD will be available from January 2029 to June 2029
Access criteria: Researchers with an approved protocol will be abel to access the databank upon reasonable request to the study PI
Data sharing details ↗ · fbai.org.br
Started May 2026 (actual). Primary completion is estimated for May 2028, 24 months after the start.
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