Interferon Beta and Glatiramer Acetate Therapy

Interferon beta and glatiramer acetate have been mainstays of treatment in relapsingremitting multiple sclerosis for two decades. Remarkable advances in our understanding of immune function and dysfunction as well as increasingly sophisticated clinical trial design have stemmed from efforts to better understand these drugs. In this chapter, we review the history of their development and elaborate on known and theorized mechanisms of action. We describe the pivotal clinical trials that have led to their widespread use. We evaluate the clinical use of the drugs including tolerability, side effects, and efficacy measures. Finally, we look to the future of interferon beta and glatiramer acetate in the context of an ever growing armamentarium of treatments for relapsing remitting multiple sclerosis.     

Natalizumab is effective as second line therapy in the treatment of relapsing remitting multiple sclerosis

Background:  Natalizumab has been recommended for the treatment of patients with relapsing remitting multiple sclerosis with insufficient response to interferon-beta (IFN-beta) or glatiramer acetate (GA).
Method:  Prospective, observational study.
Results:  We found a reduction of the annualized relapse rate from 2.1 under IFN-beta or GA to 0.2 one year after switching to natalizumab. There were 94% fewer gadolinium enhancing lesions with natalizumab.
Conclusion:  Natalizumab reduced short term clinical and MRI activity in second line therapy and efficacy is comparable to first line therapy as demonstrated in the pivotal trials.     

Copaxone's effect on MRI-monitored disease in relapsing MS is reproducible and sustained

All but 6% of the subjects with relapsing remitting MS who were randomly assigned to receive glatiramer acetate or placebo for the 9-month controlled phase of the European/Canadian MRI trial entered an open-label extension with quarterly clinical and MRI evaluations for another 9 months. There was a 54% reduction in the mean number of enhanced lesions for those converted from placebo to glatiramer acetate and an additional 24.6% reduction for those always on glatiramer acetate. Over the entire study the accumulated T2 disease burden was 34.2% less for those always on glatiramer acetate.     

Paradoxically aggressive multiple sclerosis in the face of natalizumab therapy

In the pivotal trials of natalizumab in the treatment of relapsing-remitting multiple sclerosis (AFFIRM and SENTINEL), a dramatic reduction in relapse rate, new or enlarging T2-hyperintense lesions, and mean number of gadolinium-enhancing lesions was observed. While both relapses and new MRI lesions were observed in these trials, there has been no comment on the presence of aggressive disease in the face of natalizumab treatment. I report a 31-year-old woman with relapsing remitting MS of 12 years duration who developed aggressive demyelinating disease four months after the initiation of natalizumab. The clinical worsening was accompanied by a significant increase in new large T2-hyperintense signal abnormalities and in both solid and C-shaped contrast-enhancing lesions. Neither the clinical severity nor the striking MRI abnormalities had been noted earlier in her disease course. Neutralizing antibodies to natalizumab were not detected. She subsequently responded to combination therapy of pulsed methylprednisolone and daily glatiramer acetate.     

Secondary progressive multiple sclerosis: current knowledge and future challenges

The secondary progressive phase of multiple sclerosis (MS), which is characterised by a steady accrual of fixed disability after an initial relapsing remitting course, is not clearly understood. Although there is no consensus on the mechanisms underlying such a transition to the progressive phase, epidemiological and neuroimaging studies indicate that it is probably driven by the high prevalence of neurodegenerative compared with inflammatory pathological changes. This notion is lent support by the limited efficacy of available immunomodulating and immunosuppressive treatment strategies, which seems to be further decreased in the late stages of secondary progressive MS. No established clinical or paraclinical predictors of the transition from relapsing remitting to secondary progressive MS have been described. However, the use of quantitative MRI-derived measures is warranted to monitor natural history studies and therapeutic trials of secondary progressive MS with increased reliability. In view of the small effects of immunomodulating and immunosuppressive treatments in preventing the transition to secondary progression, the development of treatments promoting neuroaxonal repair remains an important goal in this disease.     

T2 lesions and rate of progression of disability in multiple sclerosis

Background and purpose: To assess the predictive value of T2 lesions on the rate of progression of disability in multiple sclerosis (MS). Methods: We reanalyzed T2 lesion number and load on brain MRI scans, performed before 1997, of 186 MS patients, who were clinically followed. There were 90 patients with progressive MS (35 secondary progressive and 55 primary progressive), and 96 with relapsing remitting MS. The rate of progression of disability was measured by time to sustained progression of disability (defined as an increase in ≥ 1 point when the Expanded Disability Status Scale (EDSS) was 5.5 or less and an increase in EDSS of ≥ 0.5 point when the EDSS was 6.0 or higher), and by the Multiple Sclerosis Severity Score (MSSS). Results: During follow‐up (median 15 years, IQR 12–17 years), 94% of the patients with progressive MS and 50% of the patients with relapsing remitting MS had progression of disability. Higher T2 lesion number and load were modestly associated with a higher rate of disease progression on the MSSS and a shorter time to progression of disability in relapsing remitting MS, but not in progressive MS. Conclusions: Our findings indicate that the amount of T2 lesions has a small predictive value for progression of disability in relapsing remitting MS, but has no influence on the rate of progression in progressive MS.     

Mitoxantrone

Mitoxantrone is an antineoplastic agent that exerts a potent immunosuppresive effect, including suppression of B cell immunity and reduction of T cell numbers. Clinical trials have shown that mitoxantrone has a statistically significant impact on reduction of relapse rate and delays disability progression in patients with relapsing remitting (RR) multiple sclerosis (MS) or secondary progressive (SP) MS. Treatment is well tolerated, but the risk of cardiotoxicity at higher cumulative doses is likely to limit the duration of treatment. The maximum cumulative dose recommended is 140 mg/m2. In 2000, the FDA (Food and Drug Administration) approved the use of mitoxantrone for the treatment of active RRMS, SPMS and progressing relapsing (PR) MS.     

Why treat early multiple sclerosis patients?

Class 1 clinical trials demonstrated that immunomodulatory treatments (interferon beta and glatiramer acetate) reduce the disease activity and the accumulation of disability in relapsing remitting multiple sclerosis. Moreover interferon beta-1b also had similar positive effects in secondary progressive multiple sclerosis. The magnitude of these clinical effects was modest, but the reduction of inflammatory activity, as revealed by magnetic resonance imaging, was marked. Converging evidence from new pathological studies and new magnetic resonance techniques, characterized by increased pathological specificity, has shown that already in the early phases of the disease inflammatory activity determines irreversible axonal damage. Moreover, the amount of inflammatory activity at the clinical presentation of the disease has some value in predicting long-term disability. Taken together, these data indicate that patients may benefit from early treatment; the positive results of the Controlled High Risk Subjects Avonex Multiple Sclerosis Prevention Study support this conclusion.     

Sample size estimations for MRI-monitored trials of MS comparing new vs standard treatments.

The authors estimated the sample sizes needed for exploratory trials of MS assessing the efficacy of new treatments in reducing the number of new enhancing lesions vs those of interferon-beta or glatiramer acetate. The sample sizes per arm ranged from 868 (effect: 20%) to 94 (effect: 50%) for patients with relapsing-remitting MS and from 2,484 (effect: 20%) to 361 (effect: 50%) for patients with secondary progressive MS. In MS, exploratory trials of new vs available therapies require large numbers of patients, even when MR end-points are used.     

Selected issues of immunomodulating treatment in multiple sclerosis

Placebo-controlled or open trials of immunomodulating drugs shed more light upon pivotal clinical issues in relapsing-remitting and secondary progressive multiple sclerosis (RR MS, SP MS). Extension over 4 years of IFN beta-1b, IFN beta-1a s.c. and glatiramer acetate trials provided modest clinical benefit in RR MS patients. After 4-8 years of treatment an annual relapse rate decreased (0.20-0.57) and proportion of progression free RR MS patients increased significantly (56-65%). The percentages of SP MS patients without relapses increased markedly in EUSPMS, IMPACT, NASMPS and SPECTRIMS trials to 36-63. However, the treatments did not slow progression in two latter clinical investigations (p=ns). In most non-responders to IFN beta the second-line immunomodulating drugs brought about clinical improvement. About half of MS patients showed one year or longer adherence to the first immunomodulating drug and nearly one fifth benefited from the change of this drug to another immunotherapeutic agent.     

Sustained clinical benefits of glatiramer acetate in relapsing multiple sclerosis patients observed for 6 years. Copolymer 1 Multiple Sclerosis Study Group

In a randomized, placebo-controlled, double-blind study, glatiramer acetate (Copaxone) reduced the relapse rate and slowed accumulation of disability for patients with relapsing - remitting multiple sclerosis. Of the original 251 patients randomized to receive glatiramer acetate or placebo, 208 chose to continue in an open-label study with all patients receiving active drug. The majority of the original double-blind cohort continues to receive glatiramer acetate by daily subcutaneous injection and are evaluated at 6-month intervals and during suspected relapse. The data reported here are from approximately 6 years of organized evaluation, including the double-blind phase of up to 35 months and the open-label phase of over 36 months. Daily subcutaneous injections of 20 mg glatiramer acetate were well tolerated. The mean annual relapse rate of the patients who received glatiramer acetate since randomization and continued into the open-label study was 0.42 (95% confidence interval (CI), CI=0.34 - 0.51). The rate per year has continued to drop and for the sixth year is 0.23. Of the group who have received glatiramer acetate without interruption for 5 or more years, 69.3% were neurologically unchanged or have improved from baseline by at least one step on the Expanded Disability Status Scale (EDSS). Patients who left the open-label phase were surveyed by questionnaire. The majority responded, providing information about their current status and reasons for dropping out. This study demonstrates the sustained efficacy of glatiramer acetate in reducing the relapse rate and in slowing the accumulation of disability in patients with relapsing forms of multiple sclerosis. Multiple Sclerosis (2000) 6 255 - 266     

Are statins a treatment option for multiple sclerosis?

BACKGROUND: Treatment options for multiple sclerosis (MS) are limited. The immunomodulatory drugs interferon beta and glatiramer acetate are only partly effective in reducing the relapse rate, slowing disease progression, and diminishing the number and volume of lesions on MRI. Mitoxantrone is an immunosuppressant approved for the treatment of active forms of relapsing-remitting or secondary progressive MS, but is dose-limited owing to its potential cardiotoxicity. Thus, identifying new effective therapeutic options with few side-effects is highly desirable. RECENT DEVELOPMENTS: Evidence has emerged that statins, which are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, have immunomodulatory effects. Recent reports showed that statins prevent and reverse chronic and relapsing experimental autoimmune encephalomyelitis, an animal model of MS. Furthermore, in vitro experiments with human immune cells have shown an immunomodulatory profile of statins comparable to that of interferon beta. An open label clinical trial of simvastatin for MS revealed a significant decrease in the number and volume of new MRI lesions and a favourable safety profile. WHERE NEXT?: The obvious advantage of statins over existing MS therapies is their oral route of dosing. Statins might be beneficial for MS patients as monotherapy or as an add-on to established disease modifying drugs. As the evidence of the benefit of statins in MS is currently insufficient, large controlled clinical trials are needed. The first of these trials is about to start.     

Recent advances in pathogenesis and therapy of multiple sclerosis

In this article, recent advances in the research on pathogenesis and therapy of multiple sclerosis (MS) will be summarized. New evidence from clinical studies, imaging, histopathology and experimental models are discussed with a focus on neurodegenerative aspects and evidence from recent therapeutic studies. During the last decade, important advances in immunotherapy have been achieved, which proved especially useful for patients with relapsing remitting MS. The introduction of interferons and glatiramer acetate into MS therapy often leads to a stabilization of the disease course if administered adequately and early. The pathogenetic insights presented here may open new avenues for innovative immunomodulatory approaches and lead to an individualized MS therapy in the future. Neuroprotective treatment strategies aim at the protection of glial and neuronal cells.     

Immunosuppressive treatment in multiple sclerosis

Immunosuppressive therapy has been used to treat multiple sclerosis (MS) for over 30 years based on the hypothesis that MS is a T cell-mediated autoimmune disease. The most commonly used immunosuppressive agents in MS are azathioprine, cyclophosphamide, methotrexate, and mitoxantrone. Since the interferons and glatiramer acetate have become widely used in MS, immunosuppressive agents have found a role given as combination therapy or as monotherapy in instances where the interferons and glatiramer acetate are not effective in controlling the disease. Like the interferons and glatiramer acetate, immunosuppressive drugs are most efficacious in stages of MS that have an inflammatory component as evidenced by relapses and/or gadolinium-enhancing lesions on MRI or in patients in earlier stages of disease where inflammation predominates over degenerative processes in the CNS. There is no evidence of efficacy in primary progressive MS or later stages of secondary progressive MS. In our studies of cyclophosphamide, we have found that although it is a general immunosuppressant that affects both T cell and B cell functions, cyclophosphamide has selective immune effects in MS by suppressing IL-12- and Th1-type responses and enhancing Th2/Th3 responses (IL-4, IL-10, TGF-beta; eosinophils in peripheral blood). Cyclophosphamide and mitoxantrone are the most common immunosuppressive drugs used in patients with rapidly worsening MS whose disease is not controlled by beta-interferon or glatiramer acetate.     

Abnormalities of cerebral perfusion in multiple sclerosis

BACKGROUND: Measuring perfusion provides a potential indication of metabolic activity in brain tissue. Studies in multiple sclerosis (MS) have identified areas of decreased perfusion in grey matter (GM) and white matter (WM), but the pattern in clinical subgroups is unclear. OBJECTIVES: This study investigated perfusion changes in differing MS clinical subgroups on or off beta-interferon therapy using a non-invasive MRI technique (continuous arterial spin labelling) to investigate whether different clinical MS subtypes displayed perfusion changes and whether this could give a further insight into the pathological mechanisms involved. METHODS: Sixty patients (21 relapsing remitting, 14 secondary progressive, 12 primary progressive, 13 benign) and 34 healthy controls were compared. Statistical parametric mapping (SPM '99) was used to investigate regional variations in perfusion in both GM and WM. Global WM perfusion was derived by segmenting WM from images using T(1) relaxation times. RESULTS: Regions of lower perfusion in predominantly GM were observed in the primary and secondary progressive cohorts, particularly in the thalamus. Increased WM perfusion was seen in relapsing remitting and secondary progressive cohorts. CONCLUSIONS: Low GM perfusion could reflect decreased metabolism secondary to neuronal and axonal loss or dysfunction with a predilection for progressive forms of MS. Increased WM perfusion may indicate increased metabolic activity possibly due to increased cellularity and inflammation. Improved methodology and longitudinal studies may enable further investigation of regional and temporal changes, and their relationship with physical and cognitive impairment.     

Clinical and laboratory characteristics of secondary progressive MS

Secondary progressive (SP) MS follows on from but is distinct in its clinical picture from relapsing remitting (RR) MS. Diagnosis is usually straightforward except during the transitional stage when the two phenotypes merge. It is clear that most patients that start with relapsing remitting MS will develop SP disease, although the underlying pathogenesis that causes this change is subject to much debate. Clinical features such as pattern and site of symptoms, and age of onset, in the relapsing remitting stage versus progressive disease, suggests a difference in the pathophysiology. Laboratory markers may give insight into the disease mechanisms. Measures of urinary and CSF myelin basic protein-like material (MBPLM) indicate demyelination and subsequent oligodendrocyte and axonal loss. Tertiary neutralising antibodies to MBP antibodies could attenuate remission and lead to continuous progression, and neuronal antibodies found in SP disease may contribute to the axonal loss. In addition, differences in nitric oxide and other inflammatory cytokine patterns might either be secondary to or causative of the pathological mechanisms.Greater understanding of progressive MS is a priority considering permanent disability results almost entirely from this stage of the disease.     

New oral drugs for multiple sclerosis

Disease-modifying treatments are now available in relapsing–remitting and secondary progressive multiple sclerosis (MS), and their beneficial effects have been shown in several clinical studies. However, as these treatments are only partially effective in halting the MS disease process and are frequently associated with side effects and suboptimal patient adherence, new oral therapeutic approaches are warranted. This review focuses on advances in current and novel oral treatment approaches for MS. Several pivotal reports have provided promising results for new oral therapies evaluating the safety and efficacy of new agents including fingolimod, fumaric acid, cladribine, teriflunomide and laquinimod.     

Extended observations on MS patients treated with IM interferon-beta1a (Avonex): implications for modern MS trials and therapeutics

Extended observations of the pivotal phase III clinical trial of interferon-beta1a (IFNbeta1a; Avonex, Biogen) in relapsing MS patients revealed that: (1) active treatment significantly slowed the accumulation of physical disability over time, reduced clinical exacerbations and MRI brain lesions; (2) clinical efficacy did not depend on disability endpoints; (3) active treatment benefited multiple MRI measures of brain lesions; (4) cerebral atrophy occurred over 2 years in relatively mildly disabled patients; and (5) Avonex could slow the development of atrophy after the first year of treatment. Data from this study were recently used to design a new outcome measure for MS clinical trials (the Multiple Sclerosis Functional Composite), and was also the basis for two ongoing studies of IFNbeta1a: one in patients with monosymptomatic onset of MS and the other in secondary progressive MS.     

MRI metrics as surrogate markers for clinical relapse rate in relapsing-remitting MS patients

OBJECTIVE: To formally validate metrics derived from conventional MRI as surrogate endpoints for relapse rate in MS. BACKGROUND: Although metrics derived from MRI are used widely in clinical trials of MS, a formal statistical validation of MRI metrics as surrogate endpoints for clinical outcome in MS is lacking. METHODS: A validation procedure was applied to clinical and MRI data collected in the context of a randomized, double-blind, placebo-controlled trial of glatiramer acetate in patients with relapsing-remitting MS. The four Prentice operational criteria were applied to assess surrogacy for the number of new enhancing lesions, the percentage change of T2 lesion volume, and a composite MRI score based on these two metrics. RESULTS: The results of this analysis show that all three MRI measures considered by the authors had a behavior compatible with the Prentice criteria for valid surrogates. The composite MRI score correlated with relapses and accounted for much of the treatment effect on relapse rate. CONCLUSIONS: This preliminary study suggests that conventional MRI metrics might serve as valid surrogate endpoints in MS trials with glatiramer acetate or treatments thought to have a similar mode of action.     

Safety concerns and risk management of multiple sclerosis therapies

Currently, more than ten drugs have been approved for treatment of relapsing‐remitting multiple sclerosis (MS). Newer treatments may be more effective, but have less favorable safety record. Interferon‐β preparations and glatiramer acetate treatment require frequent subcutaneous or intramuscular injections and are only moderately effective, but have very rarely life‐threatening adverse effects, whereas teriflunomide and dimethyl fumarate are administered orally and have equal or better efficacy, but have more potentially severe adverse effects. The highly effective therapies fingolimod, natalizumab, daclizumab, and alemtuzumab have more serious adverse effects, some of which may be life‐threatening. The choice between drugs should be based on a benefit‐risk evaluation and tailored to the individual patient's requirements in a dialogue between the patient and treating neurologist. Patients with average disease activity can choose between dimethyl fumarate and teriflunomide or the “old injectable.” Patients with very active MS may choose a more effective drug as the initial treatment. In case of side effects on one drug, switch to another drug can be tried. Suboptimal effect of the first drug indicates escalation to a highly efficacious drug. A favorable benefit‐risk balance can be maintained by appropriate patient selection and appropriate risk management on therapy. New treatments will within the coming 1‐2 years change our current treatment algorithm for relapsing‐remitting MS.