Fingolimod treatment after natalizumab-related progressive multifocal leukoencephalopathy: three new cases

Three cases of non-carryover fingolimod-PML: Is the risk in Japan increased?

Objective

To report the course of 3 recent Japanese and European cases of fingolimod-associated progressive multifocal leukoencephalopathy (PML) and to analyze its risk factors and increased incidence in Japan.

Methods

Case series and literature review.

Results

Fingolimod-associated PML may cause both supratentorial and infratentorial lesions and a pronounced disability. Diagnosis can be challenging because PML lesions (especially infratentorial) can be initially misdiagnosed as extensive MS lesions. Immune reconstitution inflammatory syndrome (IRIS) develops a few weeks after fingolimod discontinuation and is usually mild. Age factor and therapy duration seem to be relevant because most reported patients were older than 45 years and were treated with fingolimod for more than 3 years. Combined IgG/IgM deficiency has been identified as a possible further predisposing condition in 1 case. Another patient developed an endogenous fungal skin infection, as a sign of generally compromised cellular immune response, shortly before PML. None of the reported patients had lymphocyte counts below 200/μl. Two of the 3 reported and 4 of the 21 (19%) registered fingolimod-PML cases occurred in Japan (estimated risk of 0.652 per 1,000 compared with 0.083 per 1.000 worldwide).

Conclusions

The risk of PML under fingolimod is low, but there are no reliable predictors. Despite a mild IRIS phase, it causes profound disability. Patients older than 45 years, especially with known comorbid immunodeficiencies or manifestation of other opportunistic infections, should be monitored more closely. Increased surveillance and identification of further risk factors are urgently needed in Japan.

Shortening the washout to 4 weeks when switching from natalizumab to fingolimod and risk of disease reactivation in multiple sclerosis

BACKGROUND

There is limited evidence about the optimal length of washout when switching from natalizumab to fingolimod.

OBJECTIVE

To study if a washout period of 4 weeks is associated with less disease activity compared to 8 weeks.

METHODS

25 patients with Relapsing Remitting Multiple Sclerosis were included in an open label, prospective study with a follow-up of 108 weeks. The primary endpoint (PE) was defined as "time to first relapse or MRI disease activity up to week 56". In addition, a recurrent event analysis (REA) was performed up to week 108.

RESULTS

The PE was not met (HR 0.67, 95% CI [0.22,1.97], p = 0.462). Number of relapses before stopping natalizumab was positively associated with the hazard of relapse (HR 3.91, p = 0.0117, 95% CI [1.36, 11.28]). The REA showed a reduction of the hazard to develop a relapse by 77% (HR 0.23, 95% CI [0.08, 0.69], p = 0.00854) in favor of the cohort with 4 weeks washout.

CONCLUSIONS

Our study suggests that switching from natalizumab to fingolimod with a shorter washout of 4 weeks might reduce the risk of disease reactivation after switching.

Observational Study of Switching from Natalizumab to Immunomodulatory Drugs

OBJECTIVE

To determine the effect of disease-modifying drugs (DMDs) on disease activity rebound in patients discontinuing natalizumab (NTZ).

METHODS

Twenty-one patients with relapsing-remitting multiple sclerosis (RRMS) treated with NTZ for ≥1 year and who switched to DMDs (glatiramer acetate [GA] or interferon) were followed up for 12 months in clinical practice. Clinical outcomes after NTZ cessation were assessed every 3 months for 1 year and MRI was performed at 12 months.

RESULTS

Twelve months after switching from NTZ to DMDs, there were no significant differences in the annualized relapse rate (ARR) compared to the days that NTZ was used (0.3 vs. 0.1; p = 0.083); and the ARR never reached similar values to those prior to NTZ use (1.61; p < 0.001). The percentage of relapse-free patients after switching from NTZ was 71.4%. These patients did not have lower disease activity before NTZ compared with those with clinical relapses (1.3 vs. 1.7; p = 0.302), but they had lower Expanded Disability Status Scale scores (3.4 vs. 5.7; p = 0.001). DMDs had beneficial effects on MRI parameters, as 10 of 16 patients (62.5%) presented no evidence of radiological activity 12 months after NTZ discontinuation.

CONCLUSIONS

Patients with RRMS and moderate disability who discontinued NTZ for safety reasons may benefit from the DMDs GA and interferon with no known risk for progressive multifocal leukoencephalopathy.

Assessment of immune functions and MRI disease activity in relapsing-remitting multiple sclerosis patients switching from natalizumab to fingolimod (ToFingo-Successor)

BACKGROUND

In light of the increased risk of progressive multifocal encephalopathy (PML) development under long-term treatment with the monoclonal antibody natalizumab which is approved for treatment of active relapsing remitting multiple sclerosis (RRMS), there is a clear need for alternative treatment options with comparable efficacy and reduced PML risk. One such option is fingolimod, a functional sphingosin-1-receptor antagonist that has been approved as first oral drug for treatment of active RRMS. However, the optimal switching design in terms of prevention of disease reoccurrence is still unknown. Moreover, potential additive effects of both drugs on immune functions, especially with regard to migration, have not yet been evaluated.

METHODS/DESIGN

This is an exploratory, open-label, monocentric, investigator-initiated clinical trial. Fifteen RRMS patients under stable treatment with natalizumab will receive one last natalizumab infusion followed by a wash-out period of 8 weeks before fingolimod treatment initiation for a period of 24 weeks. Disease activity under natalizumab and during switching will be closely monitored by assessment of relapse rate and disease severity as well as high-frequent high-resolution magnetic resonance imaging including quantitative diffusion tensor imaging. Immunological assays include longitudinal assessment of adhesion molecule expression, functional evaluation of the migratory capacity of immune cells in an in-vitro model of the blood-brain-barrier, and the quality of cellular antiviral immune responses.

DISCUSSION

Our trial represents the first detailed and longitudinal functional analysis of key immunological parameters in the process of switching from natalizumab and fingolimod, especially with regard to potential additive effects of both drugs on trafficking and immune surveillance. Moreover, our study will generate valuable information about even subtle disease exacerbations as consequence of natalizumab cessation, which will help to understand whether a switching protocol containing a wash-out period of 8 weeks before fingolimod treatment is appropriate in terms of disease stability.