Factors affecting the topography of nitrous oxide-induced neurological complications.

BACKGROUND: The factors underlying the topography of nitrous oxide (N2O)-induced neurological complications are unknown. METHODS: We included all consecutive patients admitted to the university hospital of Marseille for N2O-induced neurological complications in a prospective observational study. Patients underwent neurological examination, spinal cord magnetic resonance imaging, and nerve conduction studies within the first 4 weeks after admission. RESULTS: In total, 61 patients were included: 45% with myeloneuropathy, 34% with isolated myelopathy, and 21% with isolated neuropathy. On multivariable analysis, the odds of myelopathy were associated with the amount of weekly N2O consumption (~600 g cylinder per week, odds ratio [OR] = 1.11, 95% confidence interval [CI] = 1.001-1.24). The extent of the myelopathy (number of vertebral segments) was correlated with the number of ~600-g cylinders consumed weekly (ρ = 0.40, p < 0.005). The odds of neuropathy were associated with the duration of consumption (per month; OR = 1.29, 95% CI = 1.05-1.58). Mean lower-limb motor nerve amplitude was correlated with the duration of consumption (in months; ρ = -0.34, p < 0.05). CONCLUSIONS: The odds of myelopathy increased with the amount of N2O consumption, and the odds of neuropathy increased with the duration of N2O exposure, which suggests distinct pathophysiological mechanisms underlying these two neurological complications.

TNF-α inhibitors used as steroid-sparing maintenance monotherapy in parenchymal CNS sarcoidosis.

OBJECTIVE: To assess the efficacy of tumour necrosis factor-α (TNF-α) inhibitors used as steroid-sparing monotherapy in central nervous system (CNS) parenchymal sarcoidosis. METHODS: The French Multiple Sclerosis and Neuroinflammation Centers retrospectively identified patients with definite or probable CNS sarcoidosis treated with TNF-α inhibitors as steroid-sparing monotherapy. Only patients with CNS parenchymal involvement demonstrated by MRI and imaging follow-up were included. The primary outcome was the minimum dose of steroids reached that was not associated with clinical or imaging worsening during a minimum of 3 months after dosing change. RESULTS: Of the identified 38 patients with CNS sarcoidosis treated with TNF-α inhibitors, 23 fulfilled all criteria (13 females). Treatments were infliximab (n=22) or adalimumab (n=1) for a median (IQR) of 24 (17-40) months. At treatment initiation, the mean (SD) age was 41.5 (10.5) years and median (IQR) disease duration 22 (14-49.5) months. Overall, 60% of patients received other immunosuppressive agents before a TNF-α inhibitor. The mean (SD) minimum dose of steroids was 31.5 (33) mg before TNF-α inhibitor initiation and 6.5 (5.5) mg after (p=0.001). In all, 65% of patients achieved steroids dosing <6 mg/day; 61% showed clinical improvement, 30% stability and 9% disease worsening. Imaging revealed improvement in 74% of patients and stability in 26%. CONCLUSION: TNF-α inhibitors can greatly reduce steroids dosing in patients with CNS parenchymal sarcoidosis, even refractory. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that TNF-α inhibitor used as steroid-sparing monotherapy is effective for patients with CNS parenchymal sarcoidosis.

Effect of Prior Treatment With Fingolimod on Early and Late Response to Rituximab/Ocrelizumab in Patients With Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: Real-life studies noted that the risk of disease activity in multiple sclerosis (MS) after switching to rituximab (RTX) or ocrelizumab (OCR) may be unequal depending on prior disease-modifying therapy (DMT), with a higher risk associated with fingolimod (FING). METHODS: We performed a retrospective analysis of a structured prospective data collection including all consecutive patients with relapsing MS who were prescribed RTX/OCR in the MS center of Marseille. Cox proportional hazards models were applied to clinical and MRI outcomes. RESULTS: We included 321 patients with a median (interquartile range [IQR]) follow-up of 3.5 years (1.5-5) after RTX/OCR initiation. At the first RTX/OCR infusion, the mean (SD) age of patients was 37 (10) years, and the median (IQR) disease duration was 8 years (3-15): 68 patients did not receive treatment before RTX/OCR and 108 switched from FING, 47 from low efficacy therapy, and 98 from natalizumab. For statistical analysis, the group "FING" was divided into "short-FING" and "long-FING" groups according to the median value of the group's washout period (27 days). On Cox proportional hazards analysis, for only the "long-FING" group, the risk of relapse within the first 6 months of RTX/OCR was increased as compared with patients without previous DMT (hazard ratio [HR]: 8.78; 95% CI 1.72-44.86; p < 0.01). Previous DMT and washout period duration of FING had no effect on B-cell levels at 6 months. Beyond the first 6 months of RTX/OCR, age <40 years was associated with increased risk of relapse (HR: 3.93; 95% CI 1.30-11.89; p = 0.01), male sex with increased risk of new T2 lesions (HR: 2.26; 95% CI 1.08-4.74; p = 0.03), and EDSS ≥2 with increased risk of disability accumulation (HR: 3.01; 95% CI 1.34-6.74; p < 0.01). Previous DMT had no effect on the effectiveness of RTX/OCR beyond 6 months after initiation. DISCUSSION: For patients switching from FING to RTX/OCR, the risk of disease reactivation within the first 6 months of treatment was increased as compared with patients with other DMT or no previous DMT only when the washout period exceeded 26 days. Neither FING nor other previous DMT reduced the effectiveness of RTX/OCR beyond the first 6 months of treatment.

Disease Evolution in Women With Highly Active MS Who Suspended Natalizumab During Pregnancy vs Rituximab/Ocrelizumab Before Conception.

BACKGROUND AND OBJECTIVES: In women with highly active multiple sclerosis (MS), suspending rituximab (RTX) for planning pregnancy is associated with low disease reactivation. Whether this strategy reduces the risk of disease reactivity as compared with suspending natalizumab (NTZ) 3 months after conception is unclear. METHODS: We retrospectively included women with MS followed in our department during pregnancy and 1 year after birth who suspended NTZ at the end of the first trimester (option mostly proposed before 2016) or suspended RTX/ocrelizumab (RTX/OCR) in the year before conception (option proposed since 2016). RESULTS: In women who suspended NTZ, 45 pregnancies resulted in 3 miscarriages and 42 live births, including 1 newborn with major malformations. In women who suspended RTX/OCR, 37 pregnancies resulted in 3 miscarriages and 33 live births; 1 pregnancy was terminated for malformation. During pregnancy, relapse occurred in 3/42 (7.1%) patients of the NTZ group and 1/33 (3%) of the RTX/OCR group (p = 0.6). After delivery, relapse occurred in 9/42 (21.4%) patients of the NTZ group and 0/33 of the RTX/OCR group (p < 0.01). In the NTZ group, 8/9 relapses occurred in patients who restarted NTZ less than 4 weeks after delivery. The proportion of patients with gadolinium-enhanced and/or new T2 lesions on brain or spinal cord MRI performed after delivery was higher in the NTZ than RTX/OCR group (14/40 [35%] vs 1/31 [3%] patients, p = 0.001), the proportion with EDSS score progression during the period including pregnancy and the year after delivery was higher (7/42 [17%] vs 0/33 patients, p = 0.01), and the proportion fulfilling NEDA-3 during this period was lower (21/40 [53%] vs 30/31 [97%] patients, p < 0.001). DISCUSSION: Suspending RTX/OCR in the year before conception in women with highly active MS was associated with no disease reactivation during and after pregnancy. As previously reported, stopping NTZ at the end of the first trimester was associated with disease reactivation. In women receiving NTZ who are planning pregnancy, a bridge to RTX/OCR for pregnancy or continuing NTZ until week 34 are both reasonable clinical decisions. The RTX/OCR option is more comfortable for women and reduces the exposure of infants to monoclonal antibodies.

Efficacy of Rituximab Outlasts B-Cell Repopulation in Multiple Sclerosis: Time to Rethink Dosing?

BACKGROUND AND OBJECTIVES: Patients with multiple sclerosis (PwMS) receiving extended dosing of rituximab (RTX) have exhibited no return of disease activity, which suggests that maintenance of deep depletion of circulating B cells is not necessary to maintain the efficacy of RTX in MS. METHODS: This was a prospective monocentric observational study including all consecutive PwMS who started or continued RTX after 2019, when the medical staff decided to extend the dosing interval up to 24 months for all patients. Circulating B-cell subsets were monitored regularly and systematically in case of relapse. The first extended interval was analyzed. RESULTS: We included 236 PwMS (81% with relapsing-remitting MS; mean [SD] age 43 [12] years; median [range] EDSS score 4 [0-8]; mean relapse rate during the year before RTX start 1.09 [0.99]; 41.5% with MRI activity). The median number of RTX infusions before extension was 4 (1-13). At the time of the analysis, the median delay in dosing was 17 months (8-39); the median proportion of circulating CD19+ B cells was 7% (0-25) of total lymphocytes and that of CD27+ memory B cells was 4% (0-16) of total B cells. The mean annual relapse rate did not differ before and after the extension: 0.03 (0.5) and 0.04 (0.15) (p = 0.51). Similarly, annual relapse rates did not differ before and after extension in patients with EDSS score ≤3 (n = 79) or disease duration ≤5 years (n = 71) at RTX onset. During the "extended dosing" period, MRI demonstrated no lesion accrual in 228 of the 236 patients (97%). Five patients experienced clinical relapse, which was confirmed by MRI. In these patients, the level of B-cell subset reconstitution at the time of the relapse did not differ from that for patients with the same extension window. DISCUSSION: The efficacy of RTX outlasted substantial reconstitution of circulating B cells in PwMS, which suggests that renewal of the immune system underlies the prolonged effect of RTX in MS. These findings suggest that extended interval dosing of RTX that leads to a significant reconstitution of circulating B cells is safe in PwMS, could reduce the risk of infection, and could improve vaccine efficacy.