Safety and Efficacy of Monthly Long-acting IM Injection of 25mg or 40 mg GA Depot in Subjects With PPMS

Inclusion Criteria: 1. Male or female subjects diagnosed with PPMS; Diagnosis of PPMS consistent with the McDonald Criteria (revisions of 2010). 2. Age between 18 and 65 years (inclusive). 3. Subjects diagnosed with PPMS for at least 1 year and with signs of disease progression in the year prior to screening, in a rate of ≥ 1 point increase / year in the EDSS score for EDSS between 2-5 and a rate of ≥0.5 point increase / year in the EDSS scores \> 5. 4. EDSS ≥2 and ≤ 6.5 (Pyramidal or Cerebellar FS ≥ 2). 5. Documented history or the presence at screening of \> 1 oligoclonal band (OCB) if quantitative testing was done, or OCB+ if not quantitative testing done and/or positive IgG index in the cerebrospinal fluid (CSF). 6. Women of child bearing potential must have a negative urine pregnancy test at screening and use an adequate contraceptive method throughout the study. 7. Ability to provide written informed consent. Exclusion Criteria: 1. Subjects with RRMS, SPMS, or PRMS. 2. Subjects with a documented history of clinical relapse events. 3. Any relevant medical, surgical, or psychiatric condition, laboratory value, or concomitant medication which, in the opinion of the investigator, makes the subject unsuitable for study entry or potentially unable to complete all aspects of the study. 4. Contraindications or inability to successfully undergo magnetic resonance imaging (MRI) scanning. 5. Subjects diagnosed with any other than MS systemic autoimmune disease that may impact the CNS with MS like lesions such as Sarcoidosis, Sjögren's syndrome, Systemic Lupus Erythematosus (SLE), Lyme disease, APLA syndrome, etc.. Subjects with stable local/organ autoimmune disease such as psoriasis, Cutaneous Lupus erythematosus, thyroiditis (Hashimoto, grave) etc. may be considered eligible upon the PI's discretion. 6. Severe anemia (hemoglobin \<10 g/dL). 7. Abnormal renal function (serum creatinine \>1.5xULN or creatinine clearance \<30 ml/min). 8. Abnormal liver function (transaminases \>2xULN). 9. Pregnant or breast-feeding women. 10. Treatment with any kind of steroids during the last month prior to screening visit. 11. History of any anaphylactic reaction and/or serious allergic reaction following a vaccination, a known hypersensitivity to any component of the study drug, e.g. glatiramer acetate (GA), polylactic-co-glycolic acid (PLGA), polyvinyl alcohol (PVA). 12. Known or suspected history of drug or alcohol abuse. 13. Known as positive for HIV, hepatitis, VDRL, or tuberculosis. 14. Active malignant disease of any kind. However, a patient, who had a malignant disease in the past, was treated and is currently disease - free for at least 7 years, may be considered eligible, upon the PI and sponsor's discretion. 15. Previous treatment with B-cell-targeting therapies (e.g. rituximab, ocrelizumab, atacicept, belimumab or ofatumumab) within 6 months prior to screening visit. 16. Previous treatment with cladribine within 2 years prior to screening visit 17. Previous treatment with azathioprine, mitoxantrone or methotrexate within 6 months prior to screening visit. 18. Previous treatment with lymphocyte-trafficking modifiers (e.g. natalizumab, fingolimod) within 6 months prior to screening visit. Subjects should have a total lymphocyte count within normal range. 19. Previous treatment with beta interferons, intravenous immunoglobulin, plasmapheresis within 2 months prior to screening visit. 20. Previous treatment with any glatiramer acetate therapy within 3 months prior to screening visit. 21. Uncontrolled diabetes. 22. Participation in an investigational study drug within 30 days prior to study entry.