Natalizumab discontinuation: an increasingly tricky proposition

A comparison of multiple sclerosis disease activity after discontinuation of fingolimod and placebo

BACKGROUND

Cases of higher-than-expected disease activity have been reported following fingolimod discontinuation.

OBJECTIVE

The objective of this paper is to assess the risk of substantially higher-than-expected disease activity post-study drug discontinuation (SDD) at the individual patient level using data from the Phase III, placebo-controlled FREEDOMS and FREEDOMS II trials.

METHODS

Baseline gadolinium-enhancing T1-lesion volumes were used to statistically model the expected level of MRI disease activity post-SDD. Patients exceeding this level were classed as "MRI outliers." Patients with an unusually high increase in Expanded Disability Status Scale score, hospitalization for relapse, severe relapse, or relapse with incomplete recovery post-SDD were classed as "clinical outliers."

RESULTS

In FREEDOMS, the number of MRI outliers post-SDD was 2/69 (2.9%), 1/65 (1.5%) and 7/83 (8.4%) for the placebo, fingolimod 0.5 mg, and fingolimod 1.25 mg groups, respectively. In FREEDOMS II, the corresponding numbers were 4/72 (5.6%), 6/79 (7.6%) and 3/73 (4.1%). The number of clinical outliers across both trials was low. No consistent evidence of placebo vs fingolimod, dose-related or inter-trial patterns was discernable.

CONCLUSION

The low number of clinical and MRI outliers and lack of any discernible pattern within and between trials, including between placebo and fingolimod, argues against a systematic risk of higher-than-expected recurrence of disease activity following discontinuation of fingolimod.

Discontinuation of disease modifying treatments in middle aged multiple sclerosis patients. First line drugs vs natalizumab

BACKGROUND

Several disease-modifying drugs (DMD) are available for the treatment of MS, and most patients with relapsing-remitting disease are currently treated. Data on when and how DMD treatment can be safely discontinued are scarce.

METHODS

Fifteen MS patients, treated with natalizumab for >5 years without clinical and radiological signs of inflammatory disease activity, suspended treatment and were monitored with MRI examinations and clinical follow-up to determine recurrence of disease activity. This group was compared with a retrospectively analysed cohort comprising 55 MS patients treated with first-line DMDs discontinuing therapy in the time period of 1998-2015 after an analogous stable course.

RESULTS

Natalizumab discontinuers were followed for on average 19 months, and follow-up data for 56 months were available for first-line DMD quitters. Two-thirds of natalizumab treated patients experienced recurrent inflammatory disease activity, and one third had recurrence of rebound character. In contrast, 35% of first-line DMD quitters had mild recurrent disease activity, and no one exhibited rebound.

CONCLUSIONS

Withdrawal of a first-line DMD after prolonged treatment in middle-aged MS patients with stable disease appears to be relatively safe, while natalizumab withdrawal in a similar group of patients cannot be safely done without starting alternative therapy.

Neuroimaging of Natalizumab Complications in Multiple Sclerosis: PML and Other Associated Entities

Natalizumab (Tysabri) is a monoclonal antibody (α4 integrin antagonist) approved for treatment of multiple sclerosis, both for patients who fail therapy with other disease modifying agents and for patients with aggressive disease. Natalizumab is highly effective, resulting in significant decreases in rates of both relapse and disability accumulation, as well as marked decrease in MRI evidence of disease activity. As such, utilization of natalizumab is increasing, and the presentation of its associated complications is increasing accordingly. This review focuses on the clinical and neuroimaging features of the major complications associated with natalizumab therapy, focusing on the rare but devastating progressive multifocal leukoencephalopathy (PML). Associated entities including PML associated immune reconstitution inflammatory syndrome (PML-IRIS) and the emerging phenomenon of rebound of MS disease activity after natalizumab discontinuation are also discussed. Early recognition of neuroimaging features associated with these processes is critical in order to facilitate prompt diagnosis, treatment, and/or modification of therapies to improve patient outcomes.

Natalizumab discontinuation in patients with multiple sclerosis: Profiling risk and benefits at therapeutic crossroads

OBJECTIVE

The objective of this paper is to estimate the risk of reaching well-established disability milestones after withdrawal of natalizumab (NTZ) due to concern about the risk of progressive multifocal leukoencephalopathy in patients with multiple sclerosis (MS).

METHODS

Data from 415 patients with MS followed-up for six years after starting NTZ were collected from seven tertiary MS centers. The risk of disability worsening, i.e. reaching Expanded Disability Status Scale (EDSS) scores of 4.0 or 6.0, and the likelihood of experiencing a disability reduction of one EDSS point (or more), were assessed by propensity score-adjusted analyses in patients who discontinued and in those still on treatment at the end of follow-up.

RESULTS

A total of 318 patients who received standard NTZ treatment without experiencing evidence of disability worsening in the first two years were included in the six-year follow-up analysis, with 196 (61.6%) still on treatment and 122 (38.4%) discontinuing after a median time of 3.5 years. Patients in the discontinuing group had a more than two-fold increased risk of disability worsening (p = 0.007), and a 68% decreased likelihood of experiencing disability reduction (p = 0.009) compared with the continuing group.

CONCLUSION

While discussing the overall risk/benefit profile of NTZ, patients should be advised that, in case of treatment discontinuation, the risk of disability worsening is one in three, and increases to one in two if the EDSS score at NTZ start is above 3.0.

Immunological mechanism of action and clinical profile of disease-modifying treatments in multiple sclerosis

Multiple sclerosis (MS) is a life-long, potentially debilitating disease of the central nervous system (CNS). MS is considered to be an immune-mediated disease, and the presence of autoreactive peripheral lymphocytes in CNS compartments is believed to be critical in the process of demyelination and tissue damage in MS. Although MS is not currently a curable disease, several disease-modifying therapies (DMTs) are now available, or are in development. These DMTs are all thought to primarily suppress autoimmune activity within the CNS. Each therapy has its own mechanism of action (MoA) and, as a consequence, each has a different efficacy and safety profile. Neurologists can now select therapies on a more individual, patient-tailored basis, with the aim of maximizing potential for long-term efficacy without interruptions in treatment. The MoA and clinical profile of MS therapies are important considerations when making that choice or when switching therapies due to suboptimal disease response. This article therefore reviews the known and putative immunological MoAs alongside a summary of the clinical profile of therapies approved for relapsing forms of MS, and those in late-stage development, based on published data from pivotal randomized, controlled trials.

Treatment options for patients with multiple sclerosis who have a suboptimal response to interferon-β therapy

BACKGROUND AND PURPOSE

Although the first-line disease-modifying therapies (DMTs) interferon beta and glatiramer acetate have a favourable benefit-to-risk profile, they are only partially effective for treating relapsing-remitting multiple sclerosis (RRMS). The optimization of treatment in patients who do not show a maximum response to first-line therapy is critical for achieving the best long-term outcomes. Treatment strategies for patients with a suboptimal response include switching to another first-line DMT or a second-line DMT. Natalizumab and fingolimod are approved for RRMS with high disease activity in the European Union and Canada.

METHODS

A comprehensive literature search for articles published between 1990 and April 2012 was undertaken.

RESULTS

This review discusses key clinical and safety data for fingolimod and natalizumab, particularly in the patient subgroups for whom these treatments are approved. Benefit-to-risk profiles, including first-dose cardiovascular effects associated with fingolimod and the risk of progressive multifocal encephalopathy with natalizumab, are discussed.

CONCLUSION

A descriptive comparison of fingolimod and natalizumab is provided in the context of the decision-making process of how and when to switch patients who have a suboptimal response to first-line therapy.

Switching from natalizumab to fingolimod: an observational study

BACKGROUND

Multiple sclerosis patients who discontinue using natalizumab are at risk of a rebound in disease activity. However, the optimal alternative therapy is not currently known.

AIMS OF THE STUDY

We report on clinical and MRI data and patient safety in a group of relapsing-remitting multiple sclerosis patients who tested seropositive for the JC virus and who have switched from natalizumab to fingolimod because of concerns regarding PML risks.

METHODS

The test for JC virus antibodies was performed in 18 relapsing-remitting multiple sclerosis patients who were being treated with natalizumab for more than 1 year. Eight seropositive patients switched to fingolimod while the seronegative patients continued with natalizumab.

RESULTS

After switching to fingolimod, five of eight patients (63%) experienced clinical relapses, and MRI activity was detected in six of eight patients (75%). Neither clinical relapses nor MRI activity was observed in the patients who continued with natalizumab. No serious adverse effects were detected.

CONCLUSIONS

Natalizumab is an effective treatment for relapsing-remitting multiple sclerosis, but its discontinuation continues to be a complex problem. All of the therapies tried thus far, including fingolimod, have been unable to control the reactivation of the disease. Further studies addressing alternative therapies after natalizumab discontinuation are necessary.

[Alemtuzumab for relapsing-remitting multiple sclerosis. Results of two randomized controlled phase III studies]

In November 2012 the results of 2 clinical phase III trials were published which addressed the effects of alemtuzumab in patients with relapsing-remitting multiple sclerosis (MS). In the CARE-MS-I study patients with early untreated MS (EDSS ≤ 3.0, disease duration < 5 years) were included, whereas CARE-MS-II investigated the effects of alemtuzumab in patients with persisting disease activity under standard disease-modifying treatment (EDSS ≤ 5.0, disease duration < 10 years). These groups were compared to patients under treatment with frequently applied interferon β 1a (3 times  44 µg subcutaneous). Both studies clearly demonstrated a superiority of alemtuzumab compared to interferon in terms of reduction of relapse rate as well as the number of new or enlarging T2 lesions and gadolinium-enhancing lesions. Moreover, the CARE-MS-II study showed a significant delay in disease progression by alemtuzumab. The portfolio and the frequency of relevant side effects, such as infusion-related reactions, development of secondary autoimmunity or infections were within the expected range. Taken together these studies confirm the high anti-inflammatory efficacy of alemtuzumab and hence provide the first evidence of superiority of a monotherapy in direct comparison to standard disease-modifying treatment in two phase III trials in relapsing-remitting MS. These data in the context of the mode of action of alemtuzumab provide evidence for the relevance of immune cells, especially T cells, in the pathophysiology of MS. Experience with long-term effects of alemtuzumab, e.g. from the phase II extension trial as well as the side effect profile argue in favor of a sustained reprogramming of the immune system as a consequence of immune cell depletion by alemtuzumab.