Oral corticosteroid dosing regimen and long-term prognosis in generalised myasthenia gravis: a multicentre cross-sectional study in Japan

Rituximab alone is as effective as associated with steroids on naive patients with generalized myasthenia gravis

INTRODUCTION

Rituximab (RTX) has been proven effective in managing refractory generalized myasthenia gravis (MG), and its use is increasing worldwide. MG stabilization may initially require oral corticosteroid (CS) therapy, but its long-term side effects require the shortest duration of treatment. We studied the clinical effectiveness and usefulness of corticosteroids associated with RTX compared to RTX alone on MG remission.

METHODS

In a monocentric retrospective cohort in the Nice University Hospital, we compared naïve MG patients treated with RTX as first-line therapy alone (G1) or associated with CS (G2). After the RTX induction, we evaluated efficacy with the Osserman score (OS) and the requirement for any rescue therapy (IVIg or plasmapheresis).

RESULTS

Sixty-eight patients were treated with RTX, of which 19 (27.94%) benefited from an association with at least 0.5 mg/kg of corticosteroids. RTX-CS patients were more severe than RTX alone (OS for G1: 74.1 and G2: 64.94, p = 0.044). However, OS at 3 (83.44 and 83.12, p = 0.993), 6 (88.69 and 86.36, p = 0.545), 9 (82.91 and 85.73, p = 0.563), and 12 months (86.6 and 88.69, p = 0.761) from the treatment induction were similar. Rescue therapy following RTX induction was significantly higher for the RTX-CS (20.41% and 47.37%, p = 0.037). Regarding safety, adverse event rates were similar in the two groups (0% and 14.29%, p = 0.178).

CONCLUSION

We suggest that RTX alone is as effective as RTX-CS in MG patients, indicating that avoiding steroids could reduce side effects, decrease rescue therapies, and not affect MG outcomes.

Effectiveness of early cycles of fast-acting treatment in generalised myasthenia gravis

BACKGROUND

Early fast-acting treatment (EFT) is the aggressive use of fast-acting therapies such as plasmapheresis, intravenous immunoglobulin and/or intravenous high-dose methylprednisolone (IVMP) from the early phases of treatment. EFT is reportedly beneficial for early achievement of minimal manifestations (MM) or better status with ≤5 mg/day prednisolone (MM5mg), a practical therapeutic target for myasthenia gravis (MG).

OBJECTIVE

The current study aimed to clarify which specific EFT regimen is efficacious and the patient characteristics that confer sensitivity to EFT.

METHODS

We recruited a total of 1710 consecutive patients with MG who enrolled in the Japan MG Registry for this large-cohort study. Among them, 1066 with generalised MG who had received immunotherapy were analysed. Prognostic background factors were matched in a 1:1 ratio using propensity score matching analysis between patients treated with EFT (n=350) and those treated without EFT (n=350). The clinical course and time to first achieve MM5mg after starting immunotherapy was analysed in relation to treatment combinations and patient characteristics.

RESULTS

Kaplan-Meier analyses showed that EFT had a significant effect on the achievement of MM5mg (p<0.0001, log-rank test; HR 1.82, p<0.0001). Notably, EFT was efficacious for any type of MG, and the inclusion of IVMP resulted in earlier and more frequent achievement of MM5mg (p=0.0352, log-rank test; HR 1.46, p=0.0380). In addition, early administration of calcineurin inhibitors also promoted MM5mg achievement.

CONCLUSION

Early cycles of intervention with EFT and early use of calcineurin inhibitors provides long-term benefits in terms of achieving therapeutic targets for generalised MG, regardless of clinical subtype.

Rate of change in acetylcholine receptor antibody levels predicts myasthenia gravis outcome

OBJECTIVE

To investigate the association between changes in anti-acetylcholine receptor antibody (AChR Ab) levels induced by immunosuppressive treatment and myasthenia gravis (MG) prognosis at 1-year post-treatment in patients with MG.

METHODS

We included 53 consecutive AChR Ab-positive patients with MG whose AChR Ab levels were remeasured within 100 days of initiating immunosuppressive treatment (median remeasuring time post-treatment: 71 (55-84) days). The AChR Ab level reduction rate (RR-AChRAb, %/day) adjusted for the time between treatment initiation, and AChR Ab level remeasurement was calculated as follows: (pretreatment-post-treatment AChR Ab level)/pretreatment AChR Ab level/days between therapy initiation and AChR Ab level remeasurement ×100. Participants were divided into two groups based on the cut-off value of RR-AChR Ab, determined using receiver operating characteristic analyses for achieving minimal manifestation (MM) or better status at 1-year postimmunosuppressive treatment. The Myasthenia Gravis Foundation of America postintervention status and MG activity of daily living (MG-ADL) score at 1-year post-treatment were compared between the two groups.

RESULTS

The RR-AChRAb cut-off value was 0.64%/day. The high RR-AChRAb group had a higher ratio of MM or better status (90% vs 65%, p=0.03) and lower MG-ADL score (median; 1 vs 2, p=0.04) than the low RR-AChRAb group. Kaplan-Meier analyses showed the early MM achievement in the high RR-AChRAb group (p=0.002, log-rank test).

CONCLUSIONS

High RR-AChRAb is associated with a favourable outcome at 1-year post-treatment. AChR Ab remeasurement within 100 days of therapy may be useful for predicting AChR Ab-positive MG outcomes at 1-year post-treatment.

No correlation between acetylcholine receptor antibody concentration and individual clinical symptoms of myasthenia gravis: A systematic retrospective study involving 67 patients

OBJECTIVE

To investigate the correlation between acetylcholine receptor antibodies (AChR-Ab) concentration levels and individualized clinical symptoms in patients with AChR myasthenia gravis (AChR-MG) in China.

METHODS

ELISA was used to determine the concentration of AChR-Ab in patients with MG. The Myasthenia Gravis Foundation of America (MGFA) Clinical Classification, Quantitative Myasthenia Gravis (QMG) score, and MG-specific activities of daily living (MG-ADL) scoring systems were used to evaluate the clinical status of patients. Spearman correlation analysis was used to determine the correlation between the AChR-Ab concentration and clinical score. The changes in the antibody concentration and clinical score are shown in MGFA-antibody concentration-treatment plots.

RESULTS

Autoantibody detection tests were performed in 67 patients, and their clinical scores were recorded. Forty-nine patients received immunosuppressive therapy, 17 patients received pyridostigmine only, and 1 patient under thymectomy without any medication. The AChR-Ab concentration correlated with the MGFA Classification in 5 (29.4%) patients in the pyridostigmine-only group and 15 (30.6%) patients in the immunosuppressive drug group. The changes in the MGFA Classification preceded the changes in the AChR-Ab concentration in 4 (23.5%) patients treated with pyridostigmine and 10 (20.4%) patients on immunosuppressive drugs. In patients on oral non-steroidal immunosuppressants, the AChR-Ab concentration changed by more than 50%, whereas the MGFA Classification did not increase. The AChR-Ab concentration decreased in 17/32 (53.1%) patients after thymectomy, and then increased, whereas the AChR-Ab concentration increased in 15/32 (46.9%) patients and the MGFA Classification decreased in 27/32 (81.8%) patients after thymectomy. The AChR-Ab concentration presented a slight correlation with the corresponding MGFA, QMG, and MG-ADL in patients with thymoma.

DISCUSSION

In the Chinese AChR-MG population, the Changes in the AChR-Ab concentration in individuals with AChR-MG did not consistently correlate with the severity of clinical symptoms.

Long-term outcomes and prognostic factors in generalized myasthenia gravis

OBJECTIVE

This study aimed to investigate the timing of meeting the criteria for a status of "minimal manifestation (MM) or better" and the factors that influenced whether "MM or better status" or "MM or better status with an oral prednisolone (PSL) dose of 5 mg/day or less (5-mg MM)" was met in patients with acetylcholine receptor (AChR) antibody-positive generalized myasthenia gravis (MG).

METHODS

We performed a retrospective study in 93 patients with AChR antibody-positive generalized MG who were followed for 3 years after the start of immunotherapy. We reviewed clinical data, such as MG-related symptoms, the MG activities of daily living profile (MGADL) score, immunotherapy including the dose of PSL, and achievement of the status of MM or better at baseline and 3, 6, 12, 24, and 36 months after treatment.

RESULTS

An MM or better status was achieved in 60% of the patients 3 months and in 90% of the patients 2 years after initiating immunotherapy. At 2 years, 60% of the patients had achieved the treatment goal, which was an "5-mg MM". More frequent plasmapheresis and higher dose of PSL within 3 months after immunotherapy initiation were associated with difficulty in achieving the 5-mg MM status at 2 years.

CONCLUSION

Approximately 60% of the MG patients achieved the treatment goal within 2 years after treatment. PSL dose and the cumulative number of plasmapheresis procedures at 3 months after immunotherapy initiation may help identify treatment-resistant patients with MG.

Reappraisal of Oral Steroid Therapy for Myasthenia Gravis

Treatment with oral corticosteroids at high doses with an escalation and de-escalation schedule is effective against myasthena gravis (MG). In fact, the use of corticosteroids has led to a reduction in mortality to below 10% after the 1960s. However, long-term use of oral steroids above a certain dosage level is known to cause a number of problems. In 2014, the Japanese clinical guidelines for MG proposed that the first goal in MG treatment (treatment target) should be set at minimal manifestations (MM) with oral prednisolone (PSL) 5 mg/day or below, and that treatment strategies should strive to attain this level as rapidly as possible. In 2015, a multicenter, cross-sectional study revealed that higher PSL dose and longer PSL treatment do not ensure better outcome. In the absence of good response, the PSL dose should be decreased by combining with modalities such as plasma exchange/plasmapheresis and intravenous immunoglobulin (fast-acting treatments). In 2018, we conducted a multicenter, cross-sectional study in a large population of Japanese patients with generalized MG, aiming to elucidate the correlation between oral PSL regimens and achievement of treatment goals. The ORs for low vs. high dose to achieve treatment goals at 1, 2, and 3 years were 10.4, 2.75, and 1.86, respectively, whereas the corresponding ORs for low vs. medium dose were 13.4, 3.99, and 4.92. Early combination with fast-acting therapy (OR 2.19 at 2 years, 2.11 at 3 years) or combination with calcineurin inhibitors (OR 2.09 at 2 years, 2.36 at 3 years) were also positively associated with achieving treatment goals. These results indicate that early combination of low-dose PSL regimens with other therapies is the key for early achievement of treatment goals in generalized MG. However, even with this regimen, ~35% of patients did not achieve the treatment target after 3 years. These results suggest the limitation of the current oral corticosteroid therapy. We need to develop new treatment options to increase the rate of satisfactory outcome.

Prognostic Analysis of Thymoma-Associated Myasthenia Gravis (MG) in Chinese Patients and Its Implication of MG Management: Experiences from a Tertiary Hospital

BACKGROUND

Myasthenia gravis (MG) is an autoantibody-mediated neuromuscular disorder. Approximately 10-20% of all MG patients experience thymoma (benign tumor arising from thymus tissue). Thymectomy has been the standard of care for thymomatous myasthenia gravis (TMG). However, the clinical outcome of TMG after thymectomy has not been sufficiently studied, especially the long-term prognosis. Therefore, the aim of this study was to analyze the clinical characteristics contributing to the prognostic factors of TMG.

METHODS

We reviewed 70 TMG patients in the Xiangya Hospital and classified them into the minimal manifestation (MM) group and No MM group, according to the long-term treatment outcome. MM-or-better status was defined as the goal treatment for TMG patients. We collected and analyzed the demographic data, the WHO classification of thymoma, MG-associated antibody levels, disease severity, treatment-related data as well as clinical outcome at six months. Variables selected by univariate analysis were used in the multivariate logistic regression model to identify the prognostic factors.

RESULTS

The differences in clinical outcome at six months and worst QMGS were significant, while the differences in other factors were insignificant between groups. Clinical outcome at six months (OR=23.5 95% CI 2.4-231.5, P=0.007) and dyspnea before thymectomy (OR=0.2, 95% CI 0.03-0.75, P=0.021) were identified as the prognostic factors of long-term treatment.

CONCLUSION

Demographic and clinical features were similar in TMG patients treated at our hospital. The early achievement of MM-or-better status may indicate a good outcome in the long term. Dyspnea before thymectomy appears to associate with a poor prognosis.

Maintenance immunosuppression in myasthenia gravis, an update

Therapies for myasthenia gravis (MG) include symptomatic and immunosuppressive/immunomodulatory treatment. Options for immunosuppression include corticosteroids, azathioprine, mycophenolate mofetil, cyclosporine, tacrolimus, methotrexate, rituximab, cyclophosphamide, eculizumab, intravenous immunoglobulin, subcutaneous immunoglobulin, plasmapheresis, and thymectomy. The practical aspects of long-term immunosuppressive therapy in MG are critically reviewed in this article. Application of one or more of these specific therapies is guided based on known efficacy, adverse effect profile, particular disease subtype and severity, and patient co-morbidities.