The examples and perspective in this article may not represent a worldwide view of the subject.(September 2020) |
There are several ways for pharmaceuticals for treating multiple sclerosis (MS) to reach the market.
Novel pharmaceuticals cannot enter the US market without FDA approval, which typically requires evidence of safety and efficacy in human trials and large fees be submitted to the FDA and found to be adequate.
Pharmaceuticals already on the market, such as vitamin D, do not have to and may never have had do so, and the financial incentives to do so are relatively insignificant. Thus lack of approval of such drugs implies neither efficacy nor lack of efficacy.
In general, novel pharmaceuticals cannot enter a market without government approval; standards and political influences vary.
The typical path to approval in the 21st century may include basic research leading to understanding of mechanisms of disease progression and prevention such as chemical pathways, or candidate medications that aid or interfere with such pathways, which may be tested in vitro or in an animal model. Later, three typically sequential phases of testing in humans are common. Promising results regarding safety, efficacy, and side effects are generally needed at each major phase of development.
Usually the regulatory agencies approve a multiple sclerosis medication for a specific clinical course. Treatments for RRMS (relapsing-remitting), SPMS (secondary progressive), or PPMS (primary progressive) are common. Sometimes they approve it for a subtype, like highly-active MS (HAMS, inside RRMS), rapidly-worsening MS (RWMS, inside PPMS), or "active SPMS" (previous progressive-relapsing) [1]
As of 2021 [update] , the approved drugs for relapsing-remitting multiple sclerosis (RRMS) are:
There are reports comparing these treatments in front of each other. Restricting the research only to relapses, it seems that alemtuzumab is the most cost effective [21] while anti-CD20 monoclonal antibodies (Rituxan, Ocrevus) have the better safety vs. efficacy profile [22]
The courses primary progressive (PPMS) and secondary progressive (SPMS) are normally treated apart from RRMS. Besides, the regulatory agencies treat sometimes apart the cases aSPMS (Active Secondary progressive), nSPMS(non-active SPMS), HAMS (highly active) and RPMS (rapidly progressive)
Phase III programs consist of studies on large patient groups (300 to 3,000 or more) and are aimed at being the definitive assessment of how effective and safe a test drug will be. It is the last stage of drug development and is followed by a submission to the appropriate regulatory agencies (e.g., European Medicines Agency (EMA) for the European Union, the Food and Drug Administration (FDA) for the United States, Therapeutic Goods Administration (TGA) for Australia, etc.) to obtain approval for marketing. Treatment in MS Phase III studies is usually two years per patient. In July 2021, the FDA gave the go-ahead for an investigational new drug application (IND) for the phase 3 ENSURE program, which will evaluate IMU-838 in patients with relapsing-remitting multiple sclerosis (RRMS). Immunic also announced that a separate IND application for the supportive phase 2 CALLIPER trial of IMU-838 in patients with progressive multiple sclerosis has been cleared as well. The ENSURE program consists of two identical, double-blind, twin phase 3 trials, titled ENSURE-1 and ENSURE-2, designed to evaluate the efficacy, safety, and tolerability of IMU-838 in a 30-mg daily dose versus placebo in patients with RRMS. Approximately 1050 adult patients with active RRMS are expected to be enrolled in the studies and will be evaluated on time to first relapse as the primary end point. Both trials will run concurrently, with dosing of the first patient expected in the second half of 2021.2 [32]
Phase II studies are performed on mid-sized groups of patients (20 to 300) and are designed to assess whether a drug works in the targeted disease area, as well as to continue earlier safety assessments obtained in healthy volunteers. Treatment in MS phase II studies is with 4–12 months usually shorter than in phase III studies.
Phase I and medicaments used in animal models would make a huge list. Here only some of them with special interest are listed.
Because of the side effects and dangers of some medications, they are classified into first and second line. First line includes the safest but less effective compounds, i.e. interferons and glatimer acetate. [74] The second line includes the rest of the compounds and is usually a stronger medication.
Some MS organizations separate medications into three lines: [75]
Some compounds have regulatory (e.g. FDA) approval, having been shown to be safe and effective for another purpose, however, they are not approved specifically for MS. This may be because of lack of funding to go through the approval process. Some doctors prescribe them off-label or under the schema of open label research. Examples of MS drugs used off label include:
Progressive MS (PPMS and SPMS) is more difficult to treat than RRMS. Relapsing-onset variants (RO), even when they turn into progressive MS, are easier to treat than progressive-onset variants. Though difficult to treat, SPMS and progressive-relapsing MS are easier to treat than PPMS. Ocrelizumab has been approved for PPMS and for active SPMS with relapses. Mitoxantrone has been approved for them but is rarely used due to severe risks. Several therapies are under research.[ as of? ]
Cyclophosphamide (Revimmune) is in Phase III trials for secondary progressive MS. [78] It was also studied for RRMS but the company does not pursue actively this path. In a 2006 study for refractory cases it showed some effectiveness [79] A 2007 open label study found it equivalent to mitoxantrone [80] and in 2008 evidence appeared that it can reverse disability. [81]
Some PPMS patients with a special biomarker (Immunoglobulin M oligoclonal bands) have been shown to respond to standard RRMS medications, though there is only preliminary evidence waiting to be confirmed [82]
Several combinations of drugs have been tested. Some of them are couples of approved drugs. Other tests try one approved drug with one experimental substance. Finally, at some point there could appear some trials testing couples of non-approved drugs.
As of 2016, there are 10 active principles approved which are: Two interferons (interferon beta-1a and interferon beta-1b), glatiramer acetate, mitoxantrone, fingolimod, teriflunomide, [2] dimethyl fumarate [3] and finally three monoclonal antibodies (natalizumab, alemtuzumab [16] and since May 2016, daclizumab [29] [30] )
Summarizing in a table which combinations have been tried:
Interferon beta-1a | Interferon beta-1b (Betaseron) | Glatiramer acetate (Copaxone) | Mitoxantrone | Natalizumab (Tysabri) | Fingolimod (Gilenya) | Teriflunomide (Aubagio) | Dimethyl fumarate BG12 (Tecfidera) | Alemtuzumab (Lemtrada) | |
---|---|---|---|---|---|---|---|---|---|
Interferon beta-1a | — | — | — | — | — | — | — | — | — |
Interferon beta-1b (Betaseron) | NO | — | — | — | — | — | — | — | — |
Glatiramer acetate (Copaxone) | YES [127] | NO | — | — | — | — | — | — | — |
Mitoxantrone | NO | NO | YES [120] [121] | — | — | — | — | — | — |
Natalizumab (Tysabri) | YES (linked to PML) | NO | YES [122] | NO | — | — | — | — | — |
Fingolimod (Gilenya) | NO | NO | NO | NO | NO | — | — | — | — |
Teriflunomide (Aubagio) | NO | NO | NO | NO | NO | NO | — | — | — |
Dymetyl fumarate BG12 (Tecfidera) | NO | NO | NO | NO | NO | NO | NO | — | — |
Alemtuzumab (Lemtrada) [144] | NO | NO | NO | NO | NO | NO | NO | NO | — |
Atorvastatin (Lipitor) | YES | YES [136] | NO | NO | NO | NO | NO | NO | NO |
Cyclophosphamide | NO | YES | NO | NO | NO | NO | NO | NO | NO |
Inosine | YES [138] [139] | NO | NO | NO | NO | NO | NO | NO | NO |
Personalized treatment or theranostics in MS is an active field or research that is trying to predict the response to the different known medications.
Beta-interferons are contraindicated in cases of anti-AQP4 or anti-MOG seropositivity. Interferon injections can induce neutralising antibodies against them, turning the medication ineffective. IFN-β 1b is more immunogenic than IFN-β 1a, and the subcutaneous administration has a higher risk than the intramuscular administration [145] Both interferons should induce MxA (myxovirus protein A) mRNA, being its absence a negative indicator [146]
There is heterogeneity in the immunologic pathways even restricted to RRMS population, and it correlates with IFN-β response. In a small study patients were clustered into 6 distinct subsets by baseline cytokine profiles. Two subsets were associated with patients who responded poorly to therapy. Two other subsets showed a significant reduction in relapse rates and no worsening of disability. [147]
For glatimer acetate, the biomarkers for response are interleukins. IL-27 is a biomarker for response, and IL-18 and IL-4 are also possible good biomarkers [148] [149]
It also seems that phosphorylated SIRT1 expression in mRNA is also a biomarker for response. [150]
The best predictive biomarker for mitoxantrone available is the number of relapses in separate areas within the past 24 months before treatment. [151]
Natalizumab can also induce neutralising antibodies 4 to 6 months after treatment initiation. Fetuin-A (alpha-2-HS-glycoprotein) and circulating CD49 expression are emerging biomarkers for the therapeutic efficacy of natalizumab. [145]
Lymphocyte subpopulations in peripheral blood is a promising tool to select RRMS candidate for fingolimod treatment. [152]
Gadolinium enhancement before treatment initiation as a predictor of anti-CD20 response in MS. [153]
Multiple sclerosis (MS) is an autoimmune disease in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to transmit signals, resulting in a range of signs and symptoms, including physical, mental, and sometimes psychiatric problems. Symptoms include double vision, vision loss, eye pain, muscle weakness, and loss of sensation or coordination. MS takes several forms, with new symptoms either occurring in isolated attacks or building up over time. In relapsing forms of MS, between attacks, symptoms may disappear completely, although some permanent neurological problems often remain, especially as the disease advances. In progressive forms of MS, bodily function slowly deteriorates once symptoms manifest and will steadily worsen if left untreated.
Interferon beta-1a is a cytokine in the interferon family used to treat multiple sclerosis (MS). It is produced by mammalian cells, while interferon beta-1b is produced in modified E. coli. Some research indicates that interferon injections may result in an 18–38% reduction in the rate of MS relapses.
Natalizumab, sold under the brand name Tysabri among others, is a medication used to treat multiple sclerosis and Crohn's disease. It is a humanized monoclonal antibody against the cell adhesion molecule α4-integrin. It is given by intravenous infusion. The drug is believed to work by reducing the ability of inflammatory immune cells to attach to and pass through the cell layers lining the intestines and blood–brain barrier.
Mitoxantrone is an anthracenedione antineoplastic agent.
Interferon beta-1b is a cytokine in the interferon family used to treat the relapsing-remitting and secondary-progressive forms of multiple sclerosis (MS). It is approved for use after the first MS event. Closely related is interferon beta 1a, also indicated for MS, with a very similar drug profile.
Cladribine, sold under the brand name Leustatin, among others, is a medication used to treat hairy cell leukemia and B-cell chronic lymphocytic leukemia. Cladribine, sold under the brand name Mavenclad, is used for the treatment of adults with highly active forms of relapsing-remitting multiple sclerosis.
Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease that affects the central nervous system (CNS). Several therapies for it exist, although there is no known cure.
Glatiramer acetate, sold under the brand name Copaxone among others, is an immunomodulator medication used to treat multiple sclerosis. Glatiramer acetate is approved in the United States to reduce the frequency of relapses, but not for reducing the progression of disability. Observational studies, but not randomized controlled trials, suggest that it may reduce progression of disability. While a conclusive diagnosis of multiple sclerosis requires a history of two or more episodes of symptoms and signs, glatiramer acetate is approved to treat a first episode anticipating a diagnosis. It is also used to treat relapsing-remitting multiple sclerosis. It is administered by subcutaneous injection.
Inflammatory demyelinating diseases (IDDs), sometimes called Idiopathic (IIDDs) due to the unknown etiology of some of them, are a heterogenous group of demyelinating diseases - conditions that cause damage to myelin, the protective sheath of nerve fibers - that occur against the background of an acute or chronic inflammatory process. IDDs share characteristics with and are often grouped together under Multiple Sclerosis. They are sometimes considered different diseases from Multiple Sclerosis, but considered by others to form a spectrum differing only in terms of chronicity, severity, and clinical course.
Ocrelizumab, sold under the brand name Ocrevus, is a medication used for the treatment of multiple sclerosis (MS). It is a humanized anti-CD20 monoclonal antibody. It targets CD20 marker on B lymphocytes and is an immunosuppressive drug. Ocrelizumab binds to an epitope that overlaps with the epitope to which rituximab binds.
Laquinimod is an experimental immunomodulator developed by Active Biotech and Teva. It is being investigated as an oral treatment for multiple sclerosis (MS) and Huntington's disease.
Research in multiple sclerosis may find new pathways to interact with the disease, improve function, curtail attacks, or limit the progression of the underlying disease. Many treatments already in clinical trials involve drugs that are used in other diseases or medications that have not been designed specifically for multiple sclerosis. There are also trials involving the combination of drugs that are already in use for multiple sclerosis. Finally, there are also many basic investigations that try to understand the disease better and in the future may help to find new treatments.
Dirucotide (also known as MBP8298) was developed by two research scientists (Dr. Kenneth G. Warren, MD, FRCP(C) & Ingrid Catz, Senior Scientist) at the University of Alberta for the treatment of Multiple Sclerosis (MS). Dirucotide is a synthetic peptide that consists of 17 amino acids linked in a sequence identical to that of a portion of human myelin basic protein (MBP). The sequence of these 17 amino acids is
Dimethyl fumarate (DMF) is the methyl ester of fumaric acid and is named after the earth smoke plant. Dimethyl fumarate combined with three other fumaric acid esters (FAEs) is solely licensed in Germany as an oral therapy for psoriasis. Since 2013, it has been approved by the U.S. Food and Drug Administration (FDA) as a treatment option for adults with relapsing multiple sclerosis. In 2017, an oral formulation of dimethyl fumarate was approved for medical use in the European Union as a treatment for moderate-to-severe plaque psoriasis. Dimethyl fumarate is thought to have immunomodulatory properties without causing significant immunosuppression.
Ponesimod, sold under the brand name Ponvory, is a medication for the treatment of multiple sclerosis. It is a sphingosine-1-phosphate receptor modulator.
Ozanimod, sold under the brand name Zeposia, is an immunomodulatory medication for the treatment of relapsing multiple sclerosis and ulcerative colitis. It acts as a sphingosine-1-phosphate receptor (S1PR) agonist, sequestering lymphocytes to peripheral lymphoid organs and away from their sites of chronic inflammation.
Siponimod, sold under the brand name Mayzent, is a selective sphingosine-1-phosphate receptor modulator for oral use that is used for multiple sclerosis (MS). It is intended for once-daily oral administration.
Rhonda Renee Voskuhl is an American physician, research scientist, and professor. She is a member of the Brain Research Institute (BRI) at the David Geffen School of Medicine at UCLA and is the director of its Multiple Sclerosis Program. Voskuhl has published numerous scientific articles in academic journals and has served in the role of principal investigator for several treatment trials investigating potential treatments for multiple sclerosis (MS).
Otilimab is a fully human antibody which has been developed by the biotechnology company MorphoSys. It can also be referred to as HuCAL antibody, HuCAL standing for Human Combinatorial Antibody Library and being a technology used to generate monoclonal antibodies. Otilimab is directed against the granulocyte-macrophage colony stimulating factor (GM-CSF), a monomeric glycoprotein functioning as a cytokine promoting both proliferation and activation of macrophages and neutrophils.
Anti-AQP4 diseases, are a group of diseases characterized by auto-antibodies against aquaporin 4.