Inclusion Criteria:  Written informed consent obtained Men and women aged 18 and 60 years inclusive With SPMS, according to current diagnostic criteria Screening Expanded Disability Status Scale score between 4.0 and 6.5 inclusive. Screening timed 25-foot walk (average of two trials) of 9 seconds or more  Exclusion Criteria:  Individuals with retinopathy Individuals whose screening ophthalmological exam shows retinopathy Individuals with renal insufficiency (pre-existing or developing during the trial) Individuals with significant hepatic impairment (pre-existing or developing during the trial) Individuals with abnormal screening labs Individuals with cardiac arrhythmia Individuals with a prolonged QT interval: individuals with frequency corrected QT (QTc) intervals of more than 450ms (men) or 470ms (women) at the screening examination will not be included in the study, and participants with QTc intervals of greater than 500ms on any of the other ECG examinations throughout the study will be excluded from the study. Individuals with porphyria Individuals with an allergy or other intolerability to HCQ or IND Individuals who use Fampridine or 4-aminopyridine Individuals who start Fampridine or 4-aminopyridine during the trial Individuals who start Baclofen or Tizanidine during the trial Individuals who increase the dose of Baclofen or Tizanidine during the trial Individuals who receive treatment with Botulinum toxin in the leg muscles during the trial Individuals who use siponimod, amiodarone, dapsone, digoxin or antimalarial drugs other than HCQ Pregnant or breast-feeding women