A retrospective longitudinal cohort study of the clinical burden in myasthenia gravis

Myasthenia gravis in 2025: five new things and four hopes for the future

The last 10 years has brought transformative developments in the effective treatment of myasthenia gravis (MG). Beginning with the randomized trial of thymectomy in myasthenia gravis that demonstrated efficacy of thymectomy in nonthymomatous MG, several new treatment approaches have completed successful clinical trials and regulatory launch. These modalities, including B cell depletion, complement inhibition, and blockade of the neonatal Fc receptor, are now in use, offering prospects of sustained remission and neuromuscular protection in what is a long-term disease. In this review, we update our clinico-immunological review of 2016 with these important advances, examine their role in treatment algorithms, and focus attention on key issues of biomarkers for prognostication and the growing cohort of older patients, both those with long-term disease, and late-onset MG ('LOMG'). We close by expressing our four hopes for the next 5-10 years: improvements in laboratory medicine to facilitate rapid diagnosis, effective strategies for neuromuscular protection, more research into and better understanding of pathophysiology and treatment response in older individuals, and the potentially transformative role of therapies aimed at delivering a durable response such as chimeric antigen receptor (CAR) T cells. Our postscript summarizes some emerging themes in the field of serological and online biomarkers, which may develop greater stature in the next epoch.

Racial disparities in acute care utilization among individuals with myasthenia gravis

Objective

In myasthenia gravis (MG), evidence on the impact of social determinants of health on disparities in disease burden and healthcare resource utilization is limited. This study aimed to investigate the independent association between race/ethnicity and acute care utilization during the 2 years post-diagnosis among patients with MG.

Methods

A retrospective cohort study was conducted among adults (≥18 years) with newly diagnosed MG in the United States using Optum's de-identified Market Clarity Data from January 1, 2010, to December 31, 2019. Multivariable regression models were used to assess the association between acute care utilization and race/ethnicity, insurance, exacerbation at index, and other covariates.

Results

A total of 7,058 patients met the study inclusion criteria, of whom 57% (n = 4,052) identified as Caucasian, 6% (n = 445) African American, 3% (n = 235) Hispanic, 1% (n = 94) Asian, and 32% (n = 2,232) with missing race/ethnicity information. Compared with patients identifying as Caucasian, those identifying as African American had 37% higher odds of having an emergency department visit in year 1, and those identifying as Hispanic had 70% increase in odds of having a hospitalization event in year 2 post-diagnosis. Among other covariates, Medicaid usage, exacerbation at index, and number of outpatient visits were significantly associated with acute care utilization.

Conclusion

Racial disparities significantly impacted acute care utilization in the first 2 years post-MG diagnosis. Future studies should aim to examine specific factors that may contribute to disparities such as barriers to healthcare access, greater severity of MG symptoms, and poorly controlled disease.

Eculizumab in refractory myasthenia gravis: a real-world single-center experience

INTRODUCTION

Immunosuppressive treatment is effective in most Myasthenia gravis patients, but 10-15% of patients areconsidered refractory due to inadequate response or intolerance to therapy. Eculizumab, a humanized monoclonalantibody directed against C5 complement protein, was approved in Italy to treat Ab-AchR generalized refractoryMG (rMG) in October 2022.

AIM

We aim to describe a real-world Italian experience in a population of refractory myasthenia gravis patients with oneyear follow up.

METHODS

A retrospective data analysis was conducted on patients with refractory generalized MG treated with eculizumabbetween November 2022 and May 2024. Clinical assessment through specific scales (MG ADL - QMG - MGFA -PIS), rescue, and background therapy was recorded after one, three, six, and twelve months.

RESULTS

21 rMG patients were treated with eculizumab with a medium follow up of 10.4 months and 14 patients had at leastone year follow up. A clinically meaningful reduction in total MG-ADL and QMG scores was achieved in the firstmonth. It was maintained throughout the first, third, sixth, and twelfth month along with concomitant reduction ofimmunosuppressive treatments. A drastic reduction of myasthenic exacerbations and crisis was observed duringfollow up and intravenous immunoglobulin treatment was discontinued in all patients except one. The total dailydose of prednisone was significantly reduced.

DISCUSSION

This single-center real-world study confirmes safety and effectiveness of eculizumab. Eculizumab improved rapidlyall clinical outcome measures, leading to discontinuation of intravenous immunoglobulin treatment and remarkable immunosuppressant-sparing benefits.

Safety and efficacy of satralizumab in patients with generalised myasthenia gravis (LUMINESCE): a randomised, double-blind, multicentre, placebo-controlled phase 3 trial

BACKGROUND

Evidence from preclinical studies suggests that IL-6 signalling has the potential to modulate immunopathogenic mechanisms upstream of autoantibody effector mechanisms in patients with generalised myasthenia gravis. We aimed to assess the safety and efficacy of satralizumab, a humanised monoclonal antibody targeting the IL-6 receptor, in patients with generalised myasthenia gravis.

METHODS

LUMINESCE was a randomised, double-blind, placebo-controlled, multicentre, phase 3 study at 105 sites, including hospitals and clinics, globally. Eligible patients were aged 12 years and older, with seropositive generalised myasthenia gravis (autoantibodies to the acetylcholine receptor [AChR-IgG], muscle-specific kinase [MuSK-IgG], or low-density lipoprotein receptor-related protein 4 [LRP4-IgG]), a Myasthenia Gravis Foundation of America severity class II-IV, a Myasthenia Gravis Activities of Daily Living (MG-ADL) score of 5 or more (non-ocular contribution >50%), and use of stable background therapy. Patients were randomly assigned (1:1) with a permuted-block randomisation method to receive subcutaneous satralizumab (120 mg for bodyweight ≤100 kg; 180 mg for bodyweight >100 kg) or placebo at weeks 0, 2, 4, and every 4 weeks thereafter until week 24. Randomisation was stratified according to background therapy, autoantibody type, and geographical region. The primary efficacy endpoint was mean change from baseline in total MG-ADL score at week 24 in the modified intention-to-treat population (all randomised AChR-IgG-positive patients who completed at least one post-baseline MG-ADL assessment). Safety was assessed in all randomly assigned patients who received at least one dose of study drug. The open-label extension was terminated early because of the sponsor's decision to halt further development of satralizumab for treatment of generalised myasthenia gravis. This trial is registered with ClinicalTrials.gov, NCT04963270, and EudraCT, 2020-004436-21.

FINDINGS

Between Oct 19, 2021, and Aug 15, 2023, 188 patients were randomly assigned to satralizumab (n=96) or placebo (n=92). 166 AChR-IgG-positive patients (80 in the placebo group and 86 in the satralizumab group) were included in the modified intention-to-treat population. At week 24, statistically significant yet small improvements in MG-ADL score were observed with satralizumab versus placebo (adjusted mean -3·59, 95% CI -4·15 to -3·02 vs -2·57, -3·25 to -1·88; difference -1·02, -1·88 to -0·16; p=0·0120). The proportion of patients with at least one adverse event during the double-blind period was slightly higher in patients treated with satralizumab compared with patients treated with placebo (86 [90%] patients vs 67 [73%] patients). Three serious adverse events (in three [3%] patients) were reported in the satralizumab group (pneumonia, pyelonephritis, and increased lipase) compared with nine (in six [7%] patients) serious adverse events in the placebo group (COVID-19, COVID-19 pneumonia, bacterial urinary tract infection, chest pain, back pain, and rosacea). There were no deaths or adverse events of special interest.

INTERPRETATION

Satralizumab was well tolerated and resulted in small improvements in patient-reported and clinician-reported outcomes compared with placebo at week 24 in patients with AChR-IgG-positive generalised myasthenia gravis. Further research analysing the immunological underpinnings of the observed clinical response to IL-6 signalling inhibition in patients with generalised myasthenia gravis and exploring the role of IL-6 in autoantibody-mediated diseases is warranted.

FUNDING

F Hoffmann La Roche.

Characteristics and healthcare utilization of patients with myasthenia gravis exacerbation

PURPOSE

This retrospective cohort study describes the characteristics of patients with myasthenia gravis (MG) who developed exacerbations (MG-E) and compares their healthcare utilization (HRU) to patients who did not experience exacerbations (MG-O).

METHOD

De-identified data from patients who had ≥2 MG-related diagnostic code submissions were extracted from the National Veterans Affairs Health Care Network electronic health records between 1999 and 2022. Descriptive statistics, Kaplan-Meier analysis, and per-patient per-year (PPPY) HRU were used to compare the two patient groups.

RESULTS

About 34 % (3603/10,718) of patients with MG developed exacerbations over a median follow-up of 6.8 years. Approximately 52 % of the MG-E cohort had 3 or more exacerbations over the study period, averaging 1.34 (SD 2.50) exacerbations per year. The MG-E cohort had a higher incidence of early-onset MG (7.72 % vs. 4.05 %; p < 0.0001) and higher mean Charlson Comorbidity Index scores before a diagnosis of MG (0.86 vs. 0.59; p < 0.0001). Relative to patients of other racial groups with MG-E, Hispanic and African Americans had higher cumulative incidence of exacerbations over time (p < 0.0001). Additionally, MG-E patients were five times more likely to be intubated compared to MG-O patients (p < 0.0001). Increased PPPY HRU was observed in patients with MG-E compared to patients with MG-O (outpatient visit: 25.05 vs. 14.08; inpatient admission: 0.47 vs. 0.14; ED visit: 0.69 vs. 0.26; ICU stay: 0.08 vs. 0.02, respectively; p < 0.001).

CONCLUSION

Approximately one-third of patients diagnosed with MG experienced exacerbations, with higher incidences seen among Hispanic and African Americans. MG-E was associated with higher HRU and a higher intubation risk.

Persistent symptoms, exacerbations and drug side effects despite treatment in myasthenia gravis

BACKGROUND

Generalized myasthenia gravis (gMG) is characterized by fluctuating muscle weakness. Exacerbation frequency, adverse events (AEs) related to immunosuppressant therapy and healthcare resource utilization (HCRU) are not well understood. Our study aimed to describe long-term clinical outcomes, drug-related AEs and estimated HCRU in gMG patients.

METHODS

This was a retrospective cohort analysis of clinical data from patients with gMG followed-up over eight consecutive years in a Spanish referral unit. Myasthenia Gravis Foundation of America (MGFA) clinical classification, MGFA post-interventional status (MGFA-PIS), Myasthenia Gravis Activities of Daily Living (MG-ADL) score, exacerbations, MG crises, therapies, AEs reported, specialist consultations and emergency room visits were studied biannually. An estimation of HRCU was made based on these data.

RESULTS

Some 220 patients newly diagnosed with gMG were included. Ninety percent were seropositive (84.5% anti-acetylcholine receptor [AChR], 5.9% anti-muscle-specific kinase [MuSK]). Baseline mean MG-ADL score was 5.04 points (SD 3.17), improving to 0.7 points (SD 1.40) after 8 years. Exacerbations were more frequent in years 1-2 (30.1%) but still occurred in years 7-8 (20.2%). Myasthenic crisis frequency remained 1% in years 7-8. Eighty-nine percent achieved MGFA-PIS minimal manifestations or better at 8 years. Fifty-one percent of patients reported at least one AE during the study period, leading to drug withdrawal in approximately 20% of cases. HCRU decreased between years 1-2 to years 7-8 with an estimated cost of MG from 8074.19 € per patient/year to 1679.46 €, respectively.

CONCLUSIONS

There is a group of MG patients that suffers from persistent symptoms and exacerbations (11%-20%) or MG crises, and drug AEs, which may increase disease burden and impact on the healthcare system.

Disease burden, healthcare resource utilisation, and treatment patterns in patients with newly diagnosed myasthenia gravis in England: A retrospective cohort study

BACKGROUND

Myasthenia gravis (MG), a chronic and unpredictable autoimmune disease, is associated with multiple comorbidities and high disease burden.

OBJECTIVE

To assess the disease burden, healthcare resource utilisation (HCRU), and treatment patterns of patients with newly diagnosed MG in England.

METHODS

Data from Clinical Practice Research Datalink GP practices linked to the Hospital Episode Statistics database were used. Eligible patients had ≥1 diagnostic code for MG, with the first MG diagnostic code recorded between 01 January 2010 and 31 December 2019. Non-MG controls were selected if they had no recorded MG diagnosis and ≥12 months of data. Controls were matched for age, sex and GP practice in a maximum ratio of 5:1.

RESULTS

Mean follow-up duration was 2.8 and 3.1 years for the MG and non-MG cohorts, respectively. In the MG cohort, 56% of patients were male, with a mean age of 67 years at baseline. Incidence rates of all comorbidities assessed during follow-up were higher in the MG cohort than in controls. Almost two-thirds of MG patients experienced ≥1 myasthenic exacerbation during follow-up; incidence rates (95% confidence interval) of MG exacerbations and crises were 50.0 (44.7-55.9) and 1.3 (0.8-2.0) per 100 person-years, respectively. Visits to non-neurology specialists and outpatient clinics were the most common instances of HCRU overall, each being more frequent in the MG cohort than for controls. In the first year of follow-up, acetylcholinesterase inhibitors (AChEIs) and corticosteroids were used by 56.0% and 50.2% of MG patients, respectively; the use of AChEIs declined thereafter.

CONCLUSIONS

Despite treatment, there is a high disease burden for patients with newly diagnosed MG in England, with high rates of MG exacerbation and HCRU use. Thus, there is a need for targeted treatments with sustained efficacy and improved safety to adequately manage MG symptoms and reduce MG-related disease burden.

Tracking myasthenia gravis severity over time: Insights from the French health insurance claims database

BACKGROUND AND PURPOSE

Few data are available on the course of myasthenia gravis (MG) regarding disease severity and stability over time in real-world settings. This study used the French National Health Insurance Database (SNDS) to assess markers of disease severity in patients with MG longitudinally.

METHODS

All patients with MG-related claims in the SNDS between 2013 and 2020 were identified. Patients were followed for up to 8 years after the first claim. Intensive care unit (ICU) stays, treatment with intravenous immunoglobulin (IVIg) or plasma exchange (PE), and death were documented throughout the follow-up period. Standardized mortality rates were estimated, and mortality-related variables were identified using a Cox model.

RESULTS

In all, 14,459 individuals constituted the full study population, including 6354 incident patients. In the incident population, 2199 (34.6%) were admitted to ICUs at least once, principally during the first year after the index date (N = 1477; 23.3%). This proportion decreased progressively to reach 3.0% in the seventh year. A total of 2817 patients received IVIg and 432 PE, again principally in the first year. In the full study population, the standardized mortality rate was 1.08 (95% confidence interval [CI] 1.03-1.13), being lower in men (0.95, 95% CI 0.89-1.02) than in women (1.15, 95% CI 1.07-1.23) and in patients aged >65 years (1.06, 95% CI 1.01-1.11) than in younger patients (1.50, 95% CI 1.24-1.76). Male gender, older age and higher comorbidity were independently associated with mortality.

CONCLUSIONS

A subgroup of patients with MG require ICU admission and rescue therapy with IVIg or PE, indicative of poor disease control. New therapies are needed to improve disease control and reduce disease burden.

Diabetes mellitus in patients with myasthenia gravis: a systematic review and meta-analysis

OBJECTIVES

With the prolongation of life expectancy in patients with myasthenia gravis, the number of comorbidities is increasing. Diabetes mellitus is one of the main comorbidities faced by patients with myasthenia gravis. However, there is not enough epidemiological information on diabetes mellitus. Given these limitations, the purpose of this study was to review the prevalence of diabetes mellitus in patients with myasthenia gravis and whether the myasthenia gravis is associated with an increased risk of gestational diabetes mellitus.

METHODS

PubMed, Embase, and Web of Science were searched for articles published prior to February 2024. Endnote 21 software was used to manage all relevant records. Review Manager version 5.4 and Stata version 18.0 software were used for the statistical analysis. Funnel plots and Egger's test were used to assess publication bias.

RESULTS

Twenty-four articles met the inclusion criteria and were included in the study. Among 23,516 myasthenia gravis patients, the prevalence of diabetes mellitus was 17% (95% CI 12~22%). In addition, the meta-analysis of the two studies showed that myasthenia gravis was significantly associated with an increased risk of gestational diabetes mellitus (OR = 1.56, 95% CI 1.26~1.93, p < 0.01).

CONCLUSIONS

Among the comorbidities of myasthenia gravis patients, diabetes mellitus is common, and the risk of gestational diabetes mellitus is increased in myasthenia gravis patients. These findings remind us that diabetes mellitus seems to be an important issue in the clinical management of myasthenia gravis patients and requires more attention.

Myasthenia gravis: understanding treatment patterns and direct medical costs in the Czech Republic

BACKGROUND

Myasthenia gravis (MG) is a rare autoimmune disorder with significant clinical implications, including life-threatening myasthenic crises and exacerbations. Understanding real-world treatment patterns, especially associated direct medical costs, is essential for the effective management of healthcare delivery.

METHODS

We conducted a descriptive cohort study using health administrative claims data from the Czech Republic covering more than 1,500 prevalent MG patients. Data were analysed for healthcare resource utilization, medication costs, and hospitalization rates related to MG and its complications.

RESULTS

Acetylcholine inhibitors and corticosteroids were widely prescribed, with 91.1% and 75.2% of patients receiving them at least once, respectively. Immunosuppressive therapy was given to 45.2% of patients. Myasthenic crises occurred in 2% of patients, with a mean hospitalization cost of 21,020 EUR, while exacerbations occurred in 9.2% of patients, with lower costs (5,951 EUR per hospitalization). Outpatient intravenous immunoglobulin and plasma exchange therapies incurred additional costs of 20,700 EUR and 18,206 EUR per person-year, respectively. The mean total cost per patient-year was 1,271 EUR, with significant cost differences among patients with different treatment patterns.

CONCLUSION

This study offers real-world insights into the treatment patterns and associated direct medical costs of MG in the Czech Republic. Myasthenic crises and exacerbations pose considerable cost burdens, while outpatient therapies and common pharmacotherapies are less costly. These findings are vital for healthcare planning, economic evaluation, and resource allocation, potentially leading to enhanced patient care and outcomes.

Treatment of myasthenia gravis in france: A retrospective claims database study (STAMINA)

BACKGROUND

This study aimed to describe treatment patterns in patients with myasthenia gravis (MG) in France.

METHODS

A retrospective cohort analysis was performed using the French National Health Data System (SNDS) database between 2008 and 2019. MG patients were identified using ICD-10 codes during hospitalization and/or long-term disease. We defined two adult subpopulations: a prevalent MG population of patients alive on 31/12/2019 and an incident population of newly identified patients with MG in 2012 and 2013.

RESULTS

Among the 22,079 prevalent patients, 53.1% (n = 11,498) received at least one chronic MG treatment in 2019. Among these treated patients, 52.5% received Acetylcholinesterase inhibitors (AChEIs) only, 10.2% were treated with corticosteroids (CS) ± AChEIs, 7.3% with non-steroidal immunosuppressive treatments (NSIST) and CS, 24.2% with NSIST w/o CS, and 5.8% received immunoglobulin and/or plasma exchange. Among the 2,661 incident patients, 84.6% received at least one chronic MG treatment over the 6-year follow-up period, and among them, 79.0% had at least one treatment category change. During the first semester of follow-up, 28.1% of patients were treated with an immunomodulator (CS, NSIST). Among patients starting treatment with immunomodulator, the proportion of those treated with CS decreased from 35.3% at initiation to 10.9% at 6 years.

CONCLUSION

This study illustrates the complexity of MG management. Significant CS sparing was observed over time. The frequent treatment changes especially in patients with an immunomodulator treatment reflect the high variability of the disease severity. The need for personalised treatment approaches in the management of MG to reduce the burden of disease remains.

Characterizing Myasthenia Gravis Symptoms, Exacerbations, and Crises From Neurologist's Clinical Notes Using Natural Language Processing

Background Myasthenia gravis (MG) is a rare, autoantibody neuromuscular disorder characterized by fatigable weakness. Real-world evidence based on administrative and structured datasets regarding MG may miss important details related to the clinical encounter. Examination of free-text clinical progress notes has the potential to illuminate aspects of MG care. Objective The primary objective was to examine and characterize neurologist progress notes in the care of individuals with MG regarding the prevalence of documentation of clinical subtypes, antibody status, symptomatology, and MG deteriorations, including exacerbations and crises. The secondary objectives were to categorize MG deteriorations into practical, objective states as well as examine potential sources of clinical inertia in MG care. Methods We performed a retrospective, cross-sectional analysis of de-identified neurologist clinical notes from 2017 to 2022. A qualitative analysis of physician descriptions of MG deteriorations and a discussion of risks in MG care (risk for adverse effects, risk for clinical decompensation, etc.) was performed. Results Of the 3,085 individuals with MG, clinical subtypes and antibody status identified included gMG (n = 400; 13.0%), ocular MG (n = 253; 8.2%), MG unspecified (2,432; 78.8%), seropositivity for acetylcholine receptor antibody (n = 441; 14.3%), and MuSK antibody (n = 29; 0.9%). The most common gMG manifestations were dysphagia (n = 712; 23.0%), dyspnea (n = 626; 20.3%), and dysarthria (n = 514; 16.7%). In MG crisis patients, documentation of difficulties with MG standard therapies was common (n = 62; 45.2%). The qualitative analysis of MG deterioration types includes symptom fluctuation, symptom worsening with treatment intensification, MG deterioration with rescue therapy, and MG crisis. Qualitative analysis of MG-related risks included the toxicity of new therapies and concern for worsening MG because of changing therapies. Conclusions This study of neurologist progress notes demonstrates the potential for real-world evidence generation in the care of individuals with MG. MG patients suffer fluctuating symptomatology and a spectrum of clinical deteriorations. Adverse effects of MG therapies are common, highlighting the need for effective, less toxic treatments.

Drug Use Patterns in Myasthenia Gravis: A Real-World Population-Based Cohort Study in Italy

Background: In the context of a comparative study of efficacy and safety of drugs used in rare neuromuscular and neurodegenerative diseases (CAESAR-call AIFA_FV_2012-13-14), we assessed the use patterns of drugs indicated for myasthenia gravis (MG). Methods: A retrospective cohort study was conducted based on administrative healthcare data. For a cohort of MG patients, prevalent and incident use of pyridostigmine (Py) and other indicated drugs in the first year after case identification was evaluated. Prevalent combined use of major therapies (azathioprine (Az), prednisone (Pr), vitamin D (Vd)) stratified by Py use was assessed, and a comparison between therapies at the time of MG identification and during the first year of follow-up was performed. Results: We included 2369 MG patients between 2013 and 2019. Among them, prevalent and incident Py users were 38.4% and 22.0%, respectively. In the first year of follow-up, the use of Pr was observed in 74.5% of Py prevalent users and in 82.0% of Py incident users, respectively; the use of Az was observed in 24.9% and 23.0%, respectively; and the use of Vd was observed in 53.3% and 48.2%, respectively. Among 910 Py prevalent users, 13.1% also used Az, Pr, and Vd, while 15.3% used none of these. Among 938 non-Py users, 2.7% used Az, Pr, and Vd, while 53.8% used none of these. During the first year, an increase in combined therapies was evident in incident Py users. Conclusions: Our results suggest that, for some MG patients, there may be a need for treatments that combine a rapid onset of benefit with long-term and consistent disease control. These issues may be addressed by the new treatments currently being developed. To date, more studies are needed to address the heterogeneity, quality, and generalizability of the existing data and to evaluate patterns of use, efficacy, and safety of new or emerging therapies for MG.

Cost-effectiveness of eculizumab and efgartigimod for the treatment of anti-acetylcholine receptor antibody-positive generalized myasthenia gravis

BACKGROUND

Eculizumab and efgartigimod were approved to treat anti-acetylcholine receptor antibody-positive generalized myasthenia gravis (anti-AChR Ab-positive gMG). These relatively new biological treatments provide a more rapid onset of action and improved efficacy compared with conventional immunosuppressive treatments, but at a higher cost.

OBJECTIVE

To assess the cost-effectiveness of eculizumab and, separately, efgartigimod, each added to conventional therapy vs conventional therapy alone, among patients with refractory anti-AChR Ab-positive gMG and those with anti-AChR Ab-positive gMG, respectively.

METHODS

A Markov model with 4 health states was developed, evaluating costs and utility with a 4-week cycle length and lifetime time horizon from a health care system perspective and a modified societal perspective including productivity losses from patients and caregiver burden. Model inputs were informed by key clinical trials and relevant publications identified from targeted literature reviews, and drug costs were identified from Micromedex Red Book. Costs and outcomes were discounted at 3% per year. Incremental cost-effectiveness ratios (ICERs; cost per quality-adjusted life-year [QALY] gained) were calculated for each comparison.

RESULTS

Among the corresponding populations, lifetime costs and QALYs, respectively, for eculizumab were $5,515,000 and 11.85, and for conventional therapy, $308,000 and 10.29, resulting in an ICER of $3,338,000/QALY gained. For efgartigimod, lifetime costs and QALYs, respectively, were $6,773,000 and 13.22, and for conventional therapy, $322,000 and 9.98, yielding an ICER of $1,987,000/QALY gained. After applying indirect costs in a modified societal perspective, the ICERs were reduced to $3,310,000/QALY gained for eculizumab and $1,959,000/QALY gained for efgartigimod.

CONCLUSIONS

Eculizumab and efgartigimod are rapidly acting and effective treatments for myasthenia gravis. However, at their current price, both therapies greatly exceeded common cost-effectiveness thresholds, likely limiting patient access to these therapies.

Efficacy of ravulizumab in patients with generalized myasthenia gravis by time from diagnosis: A post hoc subgroup analysis of the CHAMPION MG study

INTRODUCTION/AIMS

The CHAMPION MG study demonstrated that ravulizumab significantly improved Myasthenia Gravis-Activities of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) total scores versus placebo in adults with acetylcholine receptor antibody-positive generalized myasthenia gravis (AChR+ gMG). This post hoc analysis aimed to assess these outcomes by time from MG diagnosis.

METHODS

Changes from baseline to week 26 in MG-ADL and QMG total scores were analyzed by time from MG diagnosis to study entry (≤2 vs. >2 years). Within each subgroup, least-squares (LS) mean changes for ravulizumab and placebo were compared using mixed models for repeated measures.

RESULTS

In ravulizumab-treated patients, differences in LS mean (standard error of the mean) changes from baseline to week 26 were not statistically significant in the ≤2-years subgroup versus the >2-years subgroup for MG-ADL (-4.3 [0.70] vs. -2.9 [0.37]; p = .0511) or QMG (-4.3 [0.94] vs. -2.5 [0.50]; p = .0822) scores. No clear trends were observed in the placebo group. LS mean changes from baseline were significantly greater for ravulizumab versus placebo in both the ≤2 and >2 years from diagnosis subgroups for MG-ADL and QMG scores (all p < .05). The difference in treatment effect between the ≤2-years and >2-years subgroups was not statistically significant. No clinically meaningful between-subgroup differences in treatment-emergent adverse events were observed in ravulizumab-treated patients.

DISCUSSION

Ravulizumab treatment improved clinical outcomes for patients with AChR+ gMG regardless of time from diagnosis. A numerical trend was observed favoring greater treatment effect with earlier versus later treatment after diagnosis. Further studies are required for confirmation.

Long-Term Healthcare Resource Utilization and Costs among Patients with Myasthenia Gravis: A Swedish Nationwide Population-Based Study

INTRODUCTION

Healthcare costs and societal impact of myasthenia gravis (MG), a potentially life-threatening rare, chronic neuromuscular disease, are sparsely studied. We assessed healthcare resource utilization (HCRU) and associated costs among patients with newly diagnosed (ND) and preexisting (PE) MG in Sweden.

METHODS

This observational, retrospective cohort study used data from four linkable Swedish nationwide population-based registries. Adult MG patients receiving pharmacological treatment for MG and having ≥24-month follow-up during the period January 1, 2010, to December 31, 2017, were included.

RESULTS

A total of 1,275 patients were included in the analysis, of which 554 patients were categorized into the ND MG group and 721 into the PE MG group. Mean (±SD) age was 61.3 (±17.4) years, and 52.3% were female. In the first year post-diagnosis, ND patients had significantly higher utilization of acetylcholinesterase inhibitors (96.0% vs. 83.9%), corticosteroids (59.6% vs. 45.8%), thymectomy (12.1% vs. 0.7%), and plasma exchange (3.8% vs. 0.6%); had higher all-cause (70.9% vs. 35.8%) and MG-related (62.5% vs. 18.4%) hospitalization rates with 11 more hospitalization days (all p < 0.01) and an increased risk of hospitalization (odds ratio [95% CI] = 4.4 [3.43, 5.64]) than PE MG. In year 1 post-diagnosis, ND MG patients incurred EUR 7,302 (p < 0.01) higher total all-cause costs than PE MG, of which 84% were estimated to be MG-related and the majority (86%) were related to inpatient care. These results remained significant also after controlling for baseline demographics and comorbidities (p < 0.01). In year 2 post-diagnosis, the all-cause medical costs decreased by ∼55% for ND MG from year 1 and were comparable with PE MG.

CONCLUSION

In this population-based study, MG patients required significantly more healthcare resources in year 1 post-diagnosis than PE MG primarily due to more pharmacological treatments, thymectomies, and associated hospitalizations. These findings highlight the need to better understand potential factors including disease characteristics associated with increased health resource use and costs and need for more efficacious treatments early in the disease course.

A retrospective observational study on characteristics, treatment patterns, and healthcare resource use of patients with myasthenia gravis in England

Background

There are limited data on the real-world healthcare resource use (HCRU) and management costs of myasthenia gravis (MG) in England.

Objective

This study aims to assess the burden of disease for patients with MG in England.

Design

A retrospective, observational cohort study of adult patients diagnosed with MG, using data from the Hospital Episode Statistics data warehouse.

Methods

Patients with a first-ever recorded diagnosis of MG between 30 June 2015 and 30 June 2020 were followed up until 30 June 2021 or death, whichever occurred first. Post-diagnosis patient characteristics, treatment patterns, HCRU, and costs were described. Costs were evaluated using National Health Service reference costs.

Results

A total of 9087 patients with a median follow-up time of 2.9 years (range, 1.7-4.3 years) were included. The mean age at diagnosis was 66.5 years and 53% of the patients were male. A large proportion of patients (72.8%) were admitted as inpatients during follow-up with a mean number of 1.3 admissions. Patients hospitalized for MG-related complications spent a mean of 9.7 days per patient-year in the hospital. During follow-up, 599 (6.6% of the total cohort) and 163 (1.8%) patients had a record of rescue therapy with intravenous immunoglobulin (IVIg) and plasma exchange (PLEX), respectively. Rituximab was administered to 81 (0.9%) patients and 268 (2.9%) patients underwent thymectomy. In those patients receiving rescue therapy or rituximab, >10% received at least three cycles of the same treatment. The average annual cost of hospital admissions across all patients treated with IVIg, PLEX, and rituximab were £907,072, £689,979, and £146,726, respectively.

Conclusion

A majority of MG patients required hospitalization or accident and emergency attendance, resulting in high HCRU and costs. A subset of patients required rescue therapy (including IVIg and PLEX), rituximab administration, ventilation, or thymectomy.

Autoimmune and Non-Autoimmune Comorbidities in Myasthenic Patients of East-European Descent: A Case-Control Study

Background: As the life expectancy of patients with myasthenia gravis (MG) is improving, so the number of comorbidities continues to rise, with a potentially significant impact on the overall morbidity and mortality. The main aim of the study was to assess comorbidities of MG in a group of patients of East-European descent. Methods: We retrospectively compared 185 adult myasthenic patients with 895 sex- and age-matched controls, admitted from January 2013 to December 2021. Results: Of these patients, 60% had late-onset MG (LOMG), with a clear predominance of women in both the LOMG and early-onset (EOMG) types; and 23.8% of the patients had a radiological description consistent with thymoma. All myasthenic patients had at least one comorbidity; 20 (10.8%) of the patients associated at least one autoimmune comorbidity. Obesity (p < 0.01), type 2 diabetes (p < 0.0001), cerebrovascular diseases (p < 0.0001), essential hypertension (p < 0.01), and cardiac arrythmias (p < 0.0001) were more frequent in patients than in the control group. The granulocyte-to-lymphocyte ratio was higher in the myasthenic patients compared to the controls (p < 0.01 for LOMG). Discussion: We, thus, suggest a common chronic low-grade inflammatory background as a possible connection between MG subtypes and some of these apparently unconnected comorbidities. Conclusions: The East-European origin of the patients offered a different social and cultural angle of a disease studied mainly on populations of West-European and Asian descent.

Assessing the length of hospital stay for patients with myasthenia gravis based on the data mining MARS approach

Predicting the length of hospital stay for myasthenia gravis (MG) patients is challenging due to the complex pathogenesis, high clinical variability, and non-linear relationships between variables. Considering the management of MG during hospitalization, it is important to conduct a risk assessment to predict the length of hospital stay. The present study aimed to successfully predict the length of hospital stay for MG based on an expandable data mining technique, multivariate adaptive regression splines (MARS). Data from 196 MG patients' hospitalization were analyzed, and the MARS model was compared with classical multiple linear regression (MLR) and three other machine learning (ML) algorithms. The average hospital stay duration was 12.3 days. The MARS model, leveraging its ability to capture non-linearity, identified four significant factors: disease duration, age at admission, MGFA clinical classification, and daily prednisolone dose. Cut-off points and correlation curves were determined for these risk factors. The MARS model outperformed the MLR and the other ML methods (including least absolute shrinkage and selection operator MLR, classification and regression tree, and random forest) in assessing hospital stay length. This is the first study to utilize data mining methods to explore factors influencing hospital stay in patients with MG. The results highlight the effectiveness of the MARS model in identifying the cut-off points and correlation for risk factors associated with MG hospitalization. Furthermore, a MARS-based formula was developed as a practical tool to assist in the measurement of hospital stay, which can be feasibly supported as an extension of clinical risk assessment.

Did the speech of patients with Myasthenia Gravis decline over 4 years?

PURPOSE

To compare the speech and voice patterns of myasthenia gravis (MG) patients over four years, and correlate the results with clinical aspects of the disease.

METHODS

Data was collected for 4 years. The clinical assessment tools included the Quantitative Myasthenia Gravis (QMG) score, the Myasthenia Gravis Foundation of America (MGFA) clinical classification, and the Myasthenia Gravis Quality of Life 15-item Scale (MG-QoL). To assess speech, the recorded speaking tasks were analyzed acoustically and given auditory-perceptual ratings. Sex (equal distribution) and age (p=0.949) were used as matching criteria in the final sample, which consisted of 10 individuals in the MG group (MGG) and 10 individuals in the control group (CG).

RESULTS

After 4 years, the MG participants presented stable health status, increased mild and moderate dysarthria (from 40% to 90% of the subjects), and a significant deterioration in the respiration, phonation, and articulation subsystems. The acoustic analysis showed a decline in articulatory patterns (speech rate p=0.047, articulation rate p=0.007, mean syllable duration p=0.007) and vocal quality (increased jitter p=0.022). In the follow-up comparison, there was a significant difference between the phonation variables (shimmer and harmonic-to-noise ratio) of the MGG and CG.

CONCLUSION

The MG patients presented a decline in speech over four years and an increase in mild and moderate dysarthria. Despite presenting stable health status, their respiratory, phonatory, and articulatory subsystems worsened. There was no correlation between speech patterns and clinical characteristics of the disease (severity and motor scale).

The economic burden of individuals living with generalized myasthenia gravis and facing social determinants of health challenges

Objective

Better understanding the impact of social determinants of health (SDOH) barriers from the patient perspective is crucial to improve holistic patient support in generalized myasthenia gravis (gMG), a rare autoimmune disorder with high disease and treatment burden. The objective of this study was to identify economic challenges experienced by individuals living with gMG and SDOH barriers to better address current unmet needs.

Methods

Adults (18-75 years) living with gMG and experiencing SDOH barriers in the United States were recruited to a mixed-methods study including qualitative interviews and a web-based quantitative survey. Quotas were implemented to include a balanced spread of baseline demographic categories including insurance type, living environment, and employment status among the study sample. Direct and indirect economic challenges were identified by degree of concern.

Results

The survey was completed by 38 individuals living with gMG, the majority of whom were enrolled in public insurance and not employed. The most commonly reported major economic concerns were managing funds for emergency care (66%), loss of income (61%), and non-medical expenses (58%), highlighting the diversity of economic challenges. Individuals who were using public insurance plans, living in non-urban environments, and unemployed experienced pronounced challenges around managing non-medical costs and accessing government assistance.

Conclusion

Both direct and indirect costs were emphasized as major concerns among individuals living with gMG and SDOH barriers. Increasing access to relevant, personalized, and holistic resources, including care management, should be prioritized to improve disease management and outcomes for individuals living with gMG.

Altered Cardiac Autonomic Regulation in Individuals with Myasthenia Gravis-A Systematic Review and Meta-Analysis

The aim of this systematic review with meta-analysis was to determine differences in cardiovascular autonomic parameters between patients with myasthenia gravis (MG) and healthy controls (HCs). Two reviewers searched four electronic databases, namely PubMed, Web of Science, EMBASE, and SCOPUS, from database inception to 7 July 2023 for studies investigating cardiovascular autonomic parameters in MG vs. HCs. A random-effects meta-analysis was performed to compute Hedges' g ± 95% confidence intervals (CI). Out of a total of 2200 records, 8 observational studies with a sample size of 301 patients with MG and 454 HCs were included in the systematic review. Meta-analysis revealed lower values of expiration/inspiration ratio (g = -0.45, I2 = 74.7), baroreflex sensitivity (g = -0.56, 95%CI -0.80, -0.33; I2 = 0.3), percentage of adjacent NN intervals differing by more than 50 ms (g = -1.2, I2 = 82.8), square root of the mean of squared differences between successive beat intervals (g = -1.94, I2 = 95.1), mean of the standard deviations of all NN intervals (g = -0.83, 95%CI -1.37, -0.28; I2 = 55.5), and high frequency of HRV during tilt (g = -0.75, 95%CI -0.11, -0.39; I2 = 0). MG patients vs. HCs had higher systolic blood pressure (g = 0.39; I2 = 56.1), sympathovagal balance at rest/during tilt (LF/HF-RRIsupine, g = 0.44; I2 = 0; LF/HF-RRItilt, g = 0.86; I2 = 0; LF/HFtilt, g = 0.40; I2 = 0). As a group, MG patients have altered cardiac autonomic function, including decreased parasympathetic function, lower baroreflex sensitivity, and higher sympathovagal balance at rest and during orthostatic challenges.

Myasthenia gravis, respiratory function, and respiratory tract disease

Myasthenia gravis (MG) is characterized by muscle weakness caused by autoantibodies that bind to the postsynaptic membrane at the neuromuscular junction and impair acetylcholine receptor function. Weakness of respiratory muscles represents the most severe MG manifestation, and 10-15% of all patients experience an MG crisis with the need of mechanical ventilatory support at least once in their life. MG patients with respiratory muscle weakness need active immunosuppressive drug treatment long term, and they need regular specialist follow-up. Comorbidities affecting respiratory function need attention and optimal treatment. Respiratory tract infections can lead to MG exacerbations and precipitate an MG crisis. Intravenous immunoglobulin and plasma exchange are the core treatments for severe MG exacerbations. High-dose corticosteroids, complement inhibitors, and FcRn blockers represent fast-acting treatments that are effective in most MG patients. Neonatal myasthenia is a transient condition with muscle weakness in the newborn caused by mother's muscle antibodies. In rare cases, treatment of respiratory muscle weakness in the baby is required.

Impact of social determinants of health on individuals living with generalized myasthenia gravis and implications for patient support programs

Introduction

Social determinants of health (SDOH) are important contributors to health outcomes, and better understanding their impact on individuals diagnosed with rare, chronic diseases with high burden and unmet need is critical. Characterizing SDOH burden can help improve the design of patient support programs (PSPs), using targeted approaches to remove barriers to access.

Methods

This study used a mixed-methods strategy employing a quantitative survey, which was designed based on qualitative interviews, to understand the unmet needs and awareness/utilization of PSPs among individuals living with generalized myasthenia gravis (gMG) and experiencing SDOH barriers. The survey was completed by 38 individuals living with gMG, of which the majority were non-White/Caucasian, unemployed, low income, and enrolled in public insurance. Common SDOH challenges, awareness/utilization of available PSPs, and unmet needs were identified.

Results

Financial and mental health concerns were the most common among individuals living with gMG and experiencing SDOH barriers throughout diagnosis, accessing treatment, initiating treatment, and continuing treatment. Awareness and utilization of existing support services were low, especially when accessing treatment. Educational, financial, and personalized support with high "human touch" were commonly perceived as the most valuable resources.

Implications

To better serve the needs of individuals with gMG experiencing SDOH barriers, PSPs should use a targeted approach to offer services tailored to harder-to-reach populations. Further, providers, advocacy groups, manufacturers, and public organizations in the gMG ecosystem should strengthen collaborations with PSPs to enable individuals living with gMG to access the services they need to improve their health outcomes.

Novel Immunotherapies for Myasthenia Gravis

Myasthenia gravis (MG), a prototype autoimmune neurological disease, had its therapy centred on corticosteroids, non-steroidal broad-spectrum immunotherapy and cholinesterase inhibitors for several decades. Treatment-refractory MG and long-term toxicities of the medications have been major concerns with the conventional therapies. Advances in the immunology and pathogenesis of MG have ushered in an era of newer therapies which are more specific and efficacious. Complement inhibitors and neonatal Fc receptor blockers target disease-specific pathogenic mechanisms linked to myasthenia and have proven their efficacy in pivotal clinical studies. B cell-depleting agents, specifically rituximab, have also emerged as useful for the treatment of severe MG. Many more biologicals are in the pipeline and in diverse stages of development. This review discusses the evidence for the novel therapies and the specific issues related to their clinical use.

Electrophysiologic evaluation of myasthenia gravis and its mimics: real-world experience with single-fiber electromyography

OBJECTIVES

In centers which routinely perform single fiber electromyography (SFEMG) for suspected myasthenia gravis (MG), the additional benefit of other neurophysiologic investigations and the frequency of myasthenia mimics has not been ascertained. We aimed to illustrate the range of neurological and non-neurological myasthenia mimics referred for evaluation, and contrast features of their electrophysiologic evaluation with confirmed MG.

METHODS

We reviewed all SFEMG studies performed at our center between 1 January 2018 and 31 December 2020. Patient demographics, clinical phenotype, antibody status and final diagnosis were recorded. Electrophysiologic findings were correlated with clinical features and sensitivity analyses performed.

RESULTS

A total of 528 SFEMG studies were performed, of which 213 (41%) were abnormal. A diagnosis of MG was made in 101 individuals, including 46 with ocular MG and 35 with seronegative disease. Compared to myasthenia mimics with an abnormal SFEMG, individuals with MG had higher median jitter (mean consecutive difference 61 μs vs. 42 μs, p < 0.001) and a greater percentage of abnormal pairs (61% vs. 33%, p < 0.001) on SFEMG. Repetitive nerve stimulation was abnormal in 27.1% of people with MG and was associated with a generalized clinical phenotype (OR 4.17; 95% CI 1.67-10.48). Thirteen (2%) individuals with MG had normal SFEMG, of whom 10 were in clinical remission. Functional neurological disorders, cranial nerve palsies, primary ocular disease and myopathy were frequent myasthenia mimics.

CONCLUSION

SFEMG can be abnormal in a number of myasthenia mimics, and routine nerve conduction studies and electromyography should always be undertaken. In centers where SFEMG is performed routinely for the investigation of suspected MG, extensive proximal repetitive nerve stimulation can be foregone without substantially affecting diagnostic evaluation. Normal SFEMG in those with confirmed myasthenia gravis may help indicate clinical remission.