MS Treatment Options: DMTs, Biologics, and Emerging Therapies

How MS Treatments Work

Multiple sclerosis disease-modifying therapies do not cure MS. They reduce the frequency and severity of relapses, slow the accumulation of new lesions on MRI, and delay long-term disability progression. They do not repair existing damage.

The distinction between symptomatic treatments (managing fatigue, pain, spasticity) and disease-modifying treatments (altering the disease course) is important. This article focuses on disease-modifying therapies. Symptomatic management is a separate conversation with your neurologist [1].

Injectable DMTs: The First Generation

Interferons

Agents: Interferon beta-1a (Avonex, Rebif), interferon beta-1b (Betaseron, Extavia), peginterferon beta-1a (Plegridy)

Interferons were the first FDA-approved MS treatments (1993). They reduce relapse rates by approximately 30% compared to placebo. Their mechanism involves modulation of immune cell trafficking and cytokine balance [2].

Advantages: Decades of safety data. Well-understood side effect profile. Plegridy offers the convenience of every-2-week dosing.

Limitations: Flu-like symptoms after injection (fever, myalgia, fatigue) affect most patients initially. Injection site reactions with subcutaneous formulations. Modest efficacy compared to newer therapies. Liver function monitoring required. Neutralizing antibodies can develop and reduce efficacy over time.

Interferons remain available but have largely been replaced by more effective options as first-line therapy.

Glatiramer Acetate (Copaxone, Glatopa)

A synthetic peptide mixture that mimics myelin basic protein, shifting immune responses from pro-inflammatory Th1 toward regulatory pathways. Reduces relapse rates by approximately 30%.

Advantages: Very safe. No lab monitoring required. No serious immunosuppression. Available as a 3-times-weekly or once-daily injection. Generic available (Glatopa).

Limitations: Injection site reactions (lipoatrophy with long-term use). Modest efficacy. Daily or thrice-weekly injections.

Oral DMTs

Dimethyl Fumarate (Tecfidera) and Diroximel Fumarate (Vumerity)

Fumarates activate the Nrf2 antioxidant pathway and shift immune cell populations. They reduce relapse rates by approximately 50% and significantly reduce new MRI lesions [3].

Advantages: Oral twice-daily dosing. Good efficacy. Vumerity has improved GI tolerability over Tecfidera.

Limitations: GI side effects (flushing, nausea, diarrhea, abdominal pain) are common, especially in the first month. Lymphopenia monitoring required. Rare risk of progressive multifocal leukoencephalopathy (PML) with sustained lymphocyte counts below 500.

Fingolimod (Gilenya) and Siponimod (Mayzent)

Sphingosine-1-phosphate (S1P) receptor modulators that trap lymphocytes in lymph nodes, preventing them from entering the CNS. Fingolimod reduces relapse rates by 48-54% versus placebo [4].

Advantages: Once-daily oral dosing. Fingolimod has long track record (approved 2010). Siponimod specifically studied in secondary progressive MS (EXPAND trial showed disability benefit).

Limitations: First-dose cardiac monitoring required (risk of bradycardia). Macular edema screening. Rebound disease activity if discontinued abruptly. Varicella immunity must be confirmed before starting. Wash-out period needed before pregnancy.

Newer S1P modulators (ozanimod/Zeposia, ponesimod/Ponvory) offer similar mechanisms with potentially fewer first-dose cardiac effects.

Teriflunomide (Aubagio)

An inhibitor of dihydroorotate dehydrogenase that reduces pyrimidine synthesis in rapidly dividing lymphocytes. Reduces relapse rates by approximately 30-36%.

Advantages: Once-daily oral dosing. Well-tolerated long term.

Limitations: Hair thinning in 10-15% of patients (usually transient). Liver function monitoring. Teratogenic with very long half-life (requires accelerated elimination procedure with cholestyramine if pregnancy is planned). Modest efficacy compared to newer oral agents.

Cladribine (Mavenclad)

A purine nucleoside analog that selectively depletes lymphocytes. Given as short oral courses (10 days in year 1, 10 days in year 2), then no treatment for years 3-4 while immune reconstitution occurs.

Advantages: Treatment-free intervals (immune reconstitution therapy model). High efficacy (relapse rate reduction 55-58%). No daily medication after dosing periods. Convenient for patients who want breaks from therapy [5].

Limitations: Lymphopenia (expected and intentional). Herpes zoster risk. Theoretical malignancy concern (not confirmed in clinical data to date). Not suitable for severely immunocompromised patients.

Infusion Therapies (High-Efficacy)

Natalizumab (Tysabri)

A monoclonal antibody against alpha-4 integrin that blocks immune cell migration across the blood-brain barrier. One of the most effective DMTs available, reducing relapse rates by 68% and new MRI lesions by 83% [6].

Advantages: Extremely effective. Once-monthly IV infusion (or extended interval dosing every 6 weeks in JCV-negative patients). Rapid onset of action.

Limitations: Risk of progressive multifocal leukoencephalopathy (PML) in JCV antibody-positive patients. PML risk is highest with JCV index above 1.5, prior immunosuppressant use, and treatment duration beyond 2 years. Requires JCV antibody monitoring every 6 months. Severe rebound activity if discontinued without bridging to another DMT.

Ocrelizumab (Ocrevus)

An anti-CD20 monoclonal antibody that depletes B lymphocytes. The first therapy approved for both relapsing MS and primary progressive MS (PPMS).

Efficacy: 46-47% relapse rate reduction versus interferon beta-1a in OPERA trials. For PPMS (ORATORIO trial), 24% reduction in disability progression versus placebo [7].

Advantages: Every-6-month IV infusion. Only approved therapy for PPMS. B-cell depletion is highly effective at suppressing new inflammatory activity. Subcutaneous formulation (Ocrevus SC) now approved for faster administration.

Limitations: Infusion reactions (common, usually manageable with pre-medication). Reduced vaccine responses. Hepatitis B reactivation risk (screening required). Long-term infection risk with prolonged B-cell depletion. Hypogammaglobulinemia can develop with extended use.

Ofatumumab (Kesimpta)

Another anti-CD20 antibody, but delivered as a monthly subcutaneous self-injection rather than IV infusion. Reduces relapse rates by 50-59% versus teriflunomide in ASCLEPIOS trials [8].

Advantages: At-home self-injection (no infusion center visits). Same mechanism and similar efficacy to ocrelizumab. Monthly dosing with autoinjector pen.

Limitations: Injection site reactions. Same B-cell depletion concerns as ocrelizumab (vaccine responses, infection risk, hypogammaglobulinemia with long-term use).

Alemtuzumab (Lemtrada)

An anti-CD52 antibody that causes profound immune cell depletion followed by reconstitution. Given as two treatment courses (5 days in year 1, 3 days in year 2).

Efficacy: 49-55% relapse rate reduction versus interferon in CARE-MS trials. High rates of “no evidence of disease activity” (NEDA).

Limitations: Significant secondary autoimmunity risk (thyroid disease in 30-40%, immune thrombocytopenia in 1-2%, rare anti-GBM nephropathy). Requires 48 months of monthly monitoring after each course. Reserved for highly active disease due to safety profile [9].

Treatment Strategy: Escalation vs Early High-Efficacy

Traditionally, neurologists started with a moderate-efficacy agent (interferon or glatiramer acetate) and escalated to higher-efficacy therapies only after breakthrough disease. This “escalation” approach prioritized safety but allowed disability to accumulate before intensifying treatment.

The field is shifting toward early high-efficacy treatment (EHT), starting with potent therapies like natalizumab, ocrelizumab, or ofatumumab at diagnosis. Multiple retrospective studies show that patients started on high-efficacy therapy within the first year have less disability at 5-10 years than those who escalated [10].

The decision between approaches depends on:

• Disease activity: Highly active disease at presentation (multiple relapses, many MRI lesions, spinal cord involvement) favors early high-efficacy treatment
• Patient age and risk tolerance: Younger patients have more to lose from accumulated disability and may benefit most from aggressive early treatment
• Family planning: Pregnancy considerations influence DMT choice and timing. Glatiramer acetate and natalizumab have the most pregnancy data. Most other DMTs require washout before conception.
• JCV status: JCV positivity limits natalizumab use to shorter durations

Emerging Therapies

BTK Inhibitors

Bruton’s tyrosine kinase (BTK) inhibitors are the most anticipated pipeline therapy class for MS. Unlike anti-CD20 antibodies (which deplete B cells), BTK inhibitors modulate B-cell and microglial function without depletion. This makes them potentially effective against both the inflammatory and neurodegenerative components of MS.

Multiple BTK inhibitors are in phase III trials: tolebrutinib, fenebrutinib, evobrutinib, and remibrutinib. Early data shows efficacy comparable to anti-CD20 agents for relapsing MS, with the added potential for benefit in progressive MS through microglial modulation. Results from pivotal trials are expected through 2025-2026.

Autologous Hematopoietic Stem Cell Transplantation (aHSCT)

aHSCT involves ablating the immune system with chemotherapy and reconstituting it with the patient’s own stem cells. In highly selected patients with aggressive relapsing MS, it produces NEDA rates of 68-83% at 5 years, superior to any approved DMT [11]. It is increasingly used in specialized centers but carries treatment-related mortality of 0.3-1% and significant short-term morbidity.

Related Reading

• Multiple Sclerosis: The Evidence-Based Guide (Pillar)
• Early Signs of Multiple Sclerosis: What to Watch For
• MS Diet: What the Research Actually Shows
• Multiple Sclerosis Symptoms: Early Signs and Progression

References

1. Rae-Grant A, Day GS, Marrie RA, et al. Practice guideline recommendations summary: disease-modifying therapies for adults with multiple sclerosis. Neurology. 2018;90(17):777-788. doi:10.1212/WNL.0000000000005347
2. Interferon beta-1b is effective in relapsing-remitting multiple sclerosis. Clinical results of a multicenter, randomized, double-blind, placebo-controlled trial. The IFNB Multiple Sclerosis Study Group. Neurology. 1993;43(4):655-661. doi:10.1212/WNL.43.4.655
3. Gold R, Kappos L, Arnold DL, et al. Placebo-controlled phase 3 study of oral BG-12 for relapsing multiple sclerosis. N Engl J Med. 2012;367(12):1098-1107. doi:10.1056/NEJMoa1114287
4. Kappos L, Radue EW, O’Connor P, et al. A placebo-controlled trial of oral fingolimod in relapsing multiple sclerosis. N Engl J Med. 2010;362(5):387-401. doi:10.1056/NEJMoa0909494
5. Giovannoni G, Comi G, Cook S, et al. A placebo-controlled trial of oral cladribine for relapsing multiple sclerosis. N Engl J Med. 2010;362(5):416-426. doi:10.1056/NEJMoa0902533
6. Polman CH, O’Connor PW, Havrdova E, et al. A randomized, placebo-controlled trial of natalizumab for relapsing multiple sclerosis. N Engl J Med. 2006;354(9):899-910. doi:10.1056/NEJMoa044397
7. Hauser SL, Bar-Or A, Comi G, et al. Ocrelizumab versus interferon beta-1a in relapsing multiple sclerosis. N Engl J Med. 2017;376(3):221-234. doi:10.1056/NEJMoa1601277
8. Hauser SL, Bar-Or A, Cohen JA, et al. Ofatumumab versus teriflunomide in multiple sclerosis. N Engl J Med. 2020;383(6):546-557. doi:10.1056/NEJMoa1917246
9. Cohen JA, Coles AJ, Arnold DL, et al. Alemtuzumab versus interferon beta 1a as first-line treatment for patients with relapsing-remitting multiple sclerosis. Lancet. 2012;380(9856):1819-1828. doi:10.1016/S0140-6736(12)61769-3
10. Brown JWL, Coles A, Horakova D, et al. Association of initial disease-modifying therapy with later conversion to secondary progressive multiple sclerosis. JAMA. 2019;321(2):175-187. doi:10.1001/jama.2018.20588
11. Muraro PA, Martin R, Mancardi GL, et al. Autologous haematopoietic stem cell transplantation for treatment of multiple sclerosis. Nat Rev Neurol. 2017;13(7):391-405. doi:10.1038/nrneurol.2017.81