STRIDES - a Clinical Research Study of an Investigational New Drug to Treat Spinocerebellar Ataxia

Inclusion Criteria: 1. Signed informed consent. 2. Men and women, 18 to 75 years (inclusive) of age. 3. Clinical diagnosis of SCA3 with documented genetic confirmation. 4. m-SARA total score ≥ 4 at the screening visit. 5. m-SARA gait component score ≥ 1 at the screening visit. 6. Body Mass Index (BMI) between 18 kg/m2 and 35 kg/m2 (inclusive). 7. Stable doses of all concomitant medications for at least 30 days prior to the screening visit. 8. Negative serum beta-human chorionic gonadotropin (ß-hCG) pregnancy result at the screening visit for female participants of childbearing potential. 9. Willingness to comply with sexual abstinence or contraception guidelines of this study. Exclusion Criteria: 1. Any hereditary ataxia that is not genetically confirmed to be SCA type 3, or any type of ataxia that is acquired or secondary to another medical condition including but not limited to, alcoholism, head injury, multiple sclerosis, olivopontocerebellar atrophy, multiple system atrophy, or stroke. 2. A score of 4 on any 1 of the 4 items that comprise the m-SARA. 3. Current participation in another clinical trial or completed participation in an interventional trial less than 30 days prior to the screening visit (90 days for a biological treatment). 4. Current diagnosis and/or healthcare professional-recommended treatment (medication and/or diet) of diabetes mellitus type 1 or type 2. 5. Hemoglobin A1c (HbA1c) ≥ 6.5% at the screening visit 6. Prior treatment with SLS-005, any other IV trehalose formulation, or known hypersensitivity to trehalose. 7. Pregnant or breastfeeding. 8. History of alcohol or drug abuse within the last 2 years. 9. Chronic liver disease including Hepatitis B; Hepatitis C unless successful curative treatment is documented; human immunodeficiency virus (HIV) infection. 10. Prior history of drug-induced liver injury (DILI) and/or laboratory results at screening that indicate inadequate liver function (e.g., alanine aminotransferase \[ALT\], aspartate aminotransferase \[AST\], gamma-glutamyl transferase \[GGT\] \> 2 times the upper limit of normal \[x ULN\] and/or total bilirubin level \> 2 x ULN). 11. Laboratory results at screening that indicate inadequate renal function (e.g., estimated creatinine clearance of \< 60 mL/min calculated by the Cockcroft and Gault formula). 12. Any current cardiovascular disease or abnormality on 12-lead ECG at screening that, in the investigator's opinion, is clinically significant and could be a potential safety risk to the participant. 13. Any current psychiatric, neurological, or cognitive disorder that, in the investigator's opinion, may interfere with the participant's ability to provide informed consent or appropriately complete the study's safety or efficacy assessments. 14. Significant suicide risk as indicated by a "yes" response to question #4 or #5 under Suicidal Ideation in the past 6 months or any "yes" response under Suicidal Behavior in the past 3 years on the Columbia Suicide Severity Rating Scale (C-SSRS) during the screening visit. 15. Any other medical condition or abnormal finding during screening that, in the investigator's opinion, could confound collection or interpretation of safety or efficacy data or be a potential safety risk to the participant