Corticosteroids for Immune Reconstitution Inflammatory Syndrome (IRIS) (IRIS)

High-Dose Corticosteroids for Immune Reconstitution Inflammatory Syndrome in Patients Who Develop Progressive Multifocal Leukoencephalopathy on Natalizumab

The objectives of this study are to explore the effects of administering high-dose corticosteroids to participants who developed progressive multifocal leukoencephalopathy (PML) while on natalizumab as measured by time-course change in functional status based on Karnofsky Performance Status Index through 6 months following the completion of plasma exchange (PLEX; or equivalent), survival at 6 months following the completion of PLEX (or equivalent), and incidence and severity of adverse events (AEs) and serious adverse events (SAEs); to characterize the evolution of immune reconstitution inflammatory syndrome (IRIS) as measured by time course changes in Global Clinical Impression of Improvement (GCI-I), Symbol Digit Modalities Test (SDMT), brain magnetic resonance imaging (MRI), magnetoencephalography (MEG), chemokines, cytokines, C-reactive protein (CRP), John Cunningham virus (JCV) load and cell count in cerebrospinal fluid (CSF); and to characterize the time course elimination of serum natalizumab concentrations in the study population following the last PLEX (or equivalent) procedure.

IVMP, corticosteroids, IRIS, Progressive Multifocal Leukoencephalopathy, Immune reconstitution inflammatory syndrome, PML

Intravenous methylprednisolone (IVMP) 1 g/day administered the first 3 days of each weekly cycle, and repeated for 3 additional cycles (totaling 4 cycles). If necessary, 2 additional weekly cycles of 1 g IVMP daily for 3 days can be administered at the discretion of the investigator.

Intravenous methylprednisolone (IVMP) 1g/day for 6 days followed by an oral taper of prednisolone over 2 months (suggested dosages starting at 80 mg and tapering to 5 mg). If necessary, additional cycles of 1 g IVMP daily for 3 to 5 days can be administered at any time.

Time Course Change in Functional Status Based on Karnofsky Performance Status Index Through 6 Months Following Completion of Plasma Exchange (PLEX)

The Karnofsky Performance Status Index (KPSI) is an assessment tool intended to assist clinicians and caretakers in gauging a patient's functional status and ability to carry out activities of daily living. A KPSI of 100=normal, no complaints, no evidence of disease; 90=able to carry on normal activity, minor signs or symptoms of disease; 80=normal activity with effort, some signs or symptoms of disease; 70=cares for self, unable to carry on normal activity or do active work; 60=requires occasional assistance but is able to care for most personal needs; 50=requires considerable assistance and frequent medical care; 40=disabled, requires special care and assistance; 30=severely disabled, hospitalization is indicated, although death is not imminent; 20=very sick, hospitalization is necessary, active support treatment is necessary; 10=moribund, fatal processes progressing rapidly; 0=dead.

AE=any untoward medical occurrence in a participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. SAE=any untoward medical occurrence that at any dose: results in death; in the view of the Investigator, places the participant at immediate risk of death (a life-threatening event); however, this does not include an event that, had it occurred in a more severe form, might have caused death; requires hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; or results in a congenital anomaly/birth defect. An SAE may also be any other medically important event that, in the opinion of the Investigator, may jeopardize the participant or may require intervention to prevent one of the other outcomes listed in the definition above.

from the first dose of study treatment through the end of the treatment period (6 months) + a 4-week post-treatment period

AEs and SAEs were categorized as mild, moderate or severe according to the following criteria: Mild=barely noticeable to participant or does not make participant uncomfortable; does not influence performance or functioning; prescription drug not ordinarily needed for relief of symptom(s) but may be given because of personality of participant. Moderate=of a sufficient severity to make participant uncomfortable; performance of daily activity is influenced; participant is able to continue in study; treatment for symptom(s) may be needed. Severe=symptoms cause severe discomfort; symptoms cause incapacity or significant impact on participant's daily life; severity may cause cessation of treatment with study treatment; treatment for symptom(s) may be given and/or participant hospitalized. Please see Outcome Measure 3 for AE and SAE definitions.

from the first dose of study treatment through the end of the treatment period (6 months) + a 4-week post-treatment period

The GCI-I scale is a 7-point scale that assesses how much the participant's illness has improved or worsened relative to a baseline state at the beginning of the intervention, and rates it as: 1=very much improved; 2=much improved; 3=minimally improved; 4=no change; 5=minimally worse; 6=much worse; 7=very much worse.

Screening to 6 months following completion of PLEX (participants began treatment with intravenous methylprednisolone (IVMP) within 2 weeks after PLEX [or equivalent]).

The SDMT measures the time to pair abstract symbols with specific numbers. The test requires elements of attention, visuoperceptual processing, working memory, and psychomotor speed. The score is the number of correctly coded items from 0-110 in 90 seconds. The total score provides a measure of the speed and accuracy of symbol-digit substitution.

Screening to 6 months following completion of PLEX (participants began treatment with IVMP within 2 weeks after PLEX [or equivalent]).

The brain MRI data collected included: progressive multifocal leukoencephalopathy (PML) lesion localization, T2 hyperintense lesion volume, and signs of cerebral edema.

Screening to 6 months following completion of PLEX (participants began treatment with IVMP within 2 weeks after PLEX [or equivalent]).

Screening to 6 months following completion of PLEX (participants began treatment with IVMP within 2 weeks after PLEX [or equivalent]).

Clinical laboratory values included chemokines, cytokines, C-reactive protein (CRP), John Cunningham (JC) virus load, and cell count in cerebrospinal fluid.

Screening to 6 months following completion of PLEX (participants began treatment with IVMP within 2 weeks after PLEX [or equivalent]).

Time Course Elimination of Serum Natalizumab Concentration Following Plasma Exchange (PLEX) or Equivalent

Key Inclusion Criteria: Must have been receiving natalizumab for multiple sclerosis (MS) prior to the diagnosis or suspicion of Progressive multifocal leukoencephalopathy (PML). Subject must be willing to undergo or have completed plasma exchange (PLEX) prior to initiating study treatment. Key Exclusion Criteria: History of severe allergic or anaphylactic reactions or known hypersensitivity to any drug including hypersensitivity to corticosteroids. NOTE: Other protocol defined inclusion/exclusion criteria may apply.