Starting eculizumab as rescue therapy in refractory myasthenic crisis

Rapid response of eculizumab: a rescue therapy for ventilator-dependent refractory myasthenic crisis

Myasthenic crisis (MC) represents the most severe and life-threatening complication of myasthenia gravis (MG). Some patients exhibit refractory responses to conventional immunotherapies, including intravenous immunoglobulin and plasma exchange. This report describes a patient with MC refractory to repetitive high-dose steroids and intravenous immunoglobulin, requiring ventilator support. Within 2 days of eculizumab administration, significant improvement enabled ventilator discontinuation. Subsequent doses further ameliorated limb and pharyngeal weakness, leading to independence. A literature review that identified ten cases reported across five publications highlighted the favorable outcomes achieved with eculizumab in refractory MC, while concomitant respiratory infection was shown to complicate the recovery from MG-related respiratory failure. Although the randomized controlled trials have excluded MC cases, eculizumab has emerged as a promising option for rescue therapy in refractory MC. Larger studies that specifically include MC cases are warranted.

Prominent and fast response to eculizumab in myasthenic crisis: the potential as rescue therapy in refractory myasthenia gravis

INTRODUCTION

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease caused by antibodies against the postsynaptic membrane at the neuromuscular junction, leading to muscle weakness, fatigue, and respiratory failure in severe cases. Myasthenic crisis (MC) is a life-threatening condition which requires hospitalization and treatments with intravenous immunoglobulin, plasma exchange and high dose steroids. We report a case of a patient with refractory MC and anti-AChR antibodies positivity who started Eculizumab as rescue therapy, leading to a complete resolution of the acute neuromuscular condition.

CASE PRESENTATION

A 72-year-old man presented with bilateral ptosis, severe weakness in all limbs, dysphonia, dysphagia and dyspnea. He was diagnosed with MG with anti-AChR positivity and refractory MC. He was unresponsive to classical rescue therapy, so he underwent Eculizumab administration which resulted in a notable improvement in symptoms.

DISCUSSION

Eculizumab, a humanized monoclonal antibody that inhibits complement activation, is now approved as treatment for refractory generalized MG with anti-AChR antibodies. The use of eculizumab in refractory MC is still under investigation; however, this case report suggests that it could be a promising treatment option for patients with severe acute clinical condition.

New and Emerging Biological Therapies for Myasthenia Gravis: A Focussed Review for Clinical Decision-Making

Myasthenia gravis (MG) is a rare autoimmune disease characterised by exertion-induced muscle weakness that can lead to potentially life-threatening myasthenic crises. Detectable antibodies are directed against specific postsynaptic structures of the neuromuscular junction. MG is a chronic condition that can be improved through therapies, but to date, not cured. Standard treatment has been unchanged for decades and includes symptomatic treatment with acetylcholine-esterase inhibitors and disease-modifying treatment with steroids, steroid-sparing immunosuppressants and thymectomy. Overall, a relevant proportion of patients does not achieve a satisfactory clinical improvement under standard treatment. Additionally, long-term therapy with steroids can cause significant side effects and latency to clinical improvement with standard steroid-sparing immunosuppressants and after thymectomy can take months to years. In recent years, treatment of MG has changed fundamentally due to improved evidence from phase 3 trials and the regulatory approval of complement inhibitors and FcRn inhibitors as add-on treatment options. This provides new optimism for substantially more patients reaching minimal manifestation status and has led to a shift in treatment strategy with more targeted therapies being employed early in the course of the disease, especially in patients with high disease activity. In this focussed review, we provide an overview of the diagnosis, classification and standard treatment of MG, followed by data from randomised controlled trials on the modern drugs already available for therapy and those still in the final stages of clinical development. In the second part, we provide an overview of real-world data for already approved therapies and outline how the availability of new biologicals is changing both clinical decision-making and patient journey.

Zilucoplan for Successful Early Weaning From Mechanical Ventilation and Avoiding Tracheostomy in an 85-Year-Old Woman Experiencing Myasthenic Crisis: A Case Report

Myasthenic crisis is a life-threatening exacerbation of myasthenia gravis leading to respiratory failure, while zilucoplan is a C5 complement inhibitor that prevents complement-mediated destruction of the neuromuscular junction, thereby helping to restore muscle function and respiration. This case report describes an 85-year-old woman with late-onset myasthenia gravis who developed myasthenic crisis triggered by aspiration while eating. Initial treatment with Intravenous immunoglobulin and intravenous methylprednisolone showed limited efficacy, making weaning from mechanical ventilation challenging. Due to her advanced age, diabetes, and heart failure, plasmapheresis was considered high-risk. Zilucoplan, a C5 inhibitor administered subcutaneously, was introduced as an adjunctive therapy on Day 11, leading to rapid 50% hemolytic complement activity level reduction and significant muscle strength improvement. Extubation was achieved within four days, avoiding tracheostomy. Add-on therapy of zilucoplan provided a safe and accessible treatment option for myasthenic crisis. Previous reports have demonstrated the benefits of other C5 inhibitors and neonatal Fc receptor inhibitors in refractory myasthenic crisis. This case supports the early addition of zilucoplan with conventional rescue therapies for myasthenic crisis may have enabled earlier extubation and the avoidance of tracheostomy. Further studies are needed to determine the universal applicability of add-on therapies in myasthenic crisis, considering comorbidities and complications.

Ravulizumab and other complement inhibitors for the treatment of autoimmune disorders

Ravulizumab (ULTOMIRIS™) an intravenous glycoengineered humanized anti-C5 IgG2/4 monoclonal antibody (mAb), is a new FDA-approved treatment for Aquaporin-4-antibody (AQP4-IgG) positive Neuromyelitis Optica Spectrum Disorder (NMOSD). Based on the importance of intermediate and terminal components of the complement cascade during disease pathogenesis, in the last few years, a mAb targeting the C5 complement factor (anti-C5, eculizumab) has already been in use for treating AQP4-IgG positive NMOSD. Ravulizumab acts similarly to eculizumab, binding specifically to the complement protein C5, thereby blocking the generation of the anaphylatoxin C5a and of C5b, which is crucial for generating the membrane attack complex (C5b-9). Here, we discuss the main findings obtained during the phase 3 clinical trial (CHAMPIONNMOSD [NCT0420126]) for ravulizumab and new developments in anti-complement therapy, with other complement inhibitors for the treatment of autoimmune diseases and paroxysmal nocturnal hemoglobinuria (PNH) (zilucoplan, avacopan and, pegcetacoplan). The approval of the new long-acting anti-C5 mAb adds another therapeutic option to the already existing inhibitors of complement currently in use, increasing therapeutic options for inflammatory and autoimmune diseases.

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.

First line treatment with subcutaneous efgartigimod in impending myasthenic crisis: a case report

In acetylcholine receptor (AChR) antibody-positive generalized myasthenia gravis (gMG), neonatal Fc-receptor (FcRn) inhibition has broadened the therapeutic spectrum. Myasthenic crisis (MC), heralded by an impending myasthenic crisis (iMC), is a critical condition requiring treatments with rapid onset and sustained efficacy. Currently treatments used for iMC, including intravenous immunoglobulins and plasma exchange/immunoadsorption, have limitations, such as delayed onset of action and potential side effects. So far, there is limited data on the use of FcRn inhibitors in the management of impending or manifest MC (mMC). Here, we present a case of AChR antibody-positive gMG with iMC, where subcutaneous administration of the FcRn inhibitor efgartigimod resulted in rapid clinical remission. Within 24 h of administration, the patient exhibited significant improvement in respiratory and bulbar muscle function, preventing progression to manifest MC and the need for mechanical ventilation. This rapid response was accompanied by a marked reduction in AChR antibody level by 89.8% within 4 weeks. This case supports the potential of efgartigimod as a fast-acting and effective treatment option for managing iMC, offering an alternative to existing therapies.

Complement inhibition in seropositive generalized myasthenia gravis as rescue therapy in impending and effective treatment in frequently recurring impending myasthenic crisis-a case series

In seropositive myasthenia gravis (MG), complement inhibition has been shown to be an effective and a fast-acting therapeutic option. Myasthenic crisis (MC), usually preceded by impending MC, is a life-threatening complication requiring highly effective treatments with rapid onset of action. Currently used treatment options of MC are limited, consisting mainly of symptomatic and immune therapies, that is, intravenous immunoglobulins and plasma exchange/immunoadsorption. So far, there is only very limited data on complement inhibitors in impending or manifest MC or termination of frequently recurring impending crises. Here, we report three cases of acetylcholine receptor antibody positive MG, two with impending and one case suffering from high-frequency impending MC, where complement inhibition with eculizumab or ravulizumab resulted in a rapid and sustained remission. Meningococcal vaccination, mandatory when using complement inhibitors, did not result in symptom-worsening or manifest MC.

Towards personalized management of myasthenia gravis phenotypes: From the role of multi-omics to the emerging biomarkers and therapeutic targets

Predicting the onset, progression, and outcome of rare and chronic neurological diseases, i.e. neuromuscular diseases, is an important goal for both clinicians and researchers and should guide clinical decision-making and personalized treatment plans. A prime example is myasthenia gravis (MG), an antibody-mediated disease that affects multiple components of the postsynaptic membrane, impairing neuromuscular transmission and producing fatigable muscle weakness. MG is characterized by several clinical phenotypes, defined by a broad spectrum of factors, which have contributed to the current lack of consensus on the optimal management and treatments of this disease and its related phenotypes (subtypes). This represents a crucial challenge in MG and encourages a revolutionary change in diagnostic, prognostic and therapeutic guidelines. Emerging factors, such as demographic, clinical and pathophysiological factors, must also be considered. Consequently, the different MG phenotypes are characterized by precise biological signatures, which could represent appropriate biomarkers and targets. Here we describe and discuss these new concepts, highlighting that, thanks to multi-omics technologies, the identification of emerging diagnostic/prognostic biomarkers, such as miRNAs, and the subsequent development of new diagnostic/therapeutic algorithms could be facilitated. The latter, in turn, could facilitate the management of different MG phenotypes also in a personalized manner. Limitations and advantages are also reported.

Two-decade battle with myasthenia gravis: A breakthrough case report on the long-term success with eculizumab and ravulizumab treatment

This unique case of generalized myasthenia gravis shows sustained stability of a patient's condition for 3 years with eculizumab/ravulizumab treatment following 16 years of refractory disease. It highlights the long-term effectiveness of C5 inhibitors in a real-world setting, aiding physicians in their decision-making for refractory cases and treatment discontinuation scenarios.

Successful Control of Myasthenic Crisis After the Introduction of Ravulizumab in Myasthenia Gravis: A Case Report

This case study describes the successful use of ravulizumab in treating a 71-year-old woman with myasthenia gravis experiencing a myasthenic crisis. The patient initially presented with hypernasality and dysphagia; her medical history included untreated, complicated type 1 diabetes. The patient received several treatments approved in Japan for general myasthenia gravis, including immunoadsorption plasmapheresis, tacrolimus, intravenous immunoglobulin, and intravenous methylprednisolone. Despite these treatments, the patient's condition fluctuated, and she ultimately experienced a myasthenic crisis, which required ventilator management. The introduction of ravulizumab, a complement inhibitor targeting the complement protein C5, marked a significant turning point in the patient's treatment. Ravulizumab improved the patient's respiratory function, allowing ventilator weaning and discharge from the hospital. To the best of our knowledge, this case is the first report of successful weaning from mechanical ventilation after treatment with ravulizumab in a patient with a myasthenic crisis. This finding suggests the efficacy of ravulizumab in the management of refractory myasthenia gravis and highlights the potential of novel therapeutic approaches and combination strategies in improving the condition. Future clinical trials are needed to assess the efficacy and safety of ravulizumab in larger, more diverse populations of patients with myasthenia gravis.

Initiation response, maximized therapeutic efficacy, and post-treatment effects of biological targeted therapies in myasthenia gravis: a systematic review and network meta-analysis

Background

As targeted drug development in myasthenia gravis (MG) continues to advance, it is important to compare the efficacy of these drugs for better clinical decision-making. However, due to the varied regimens and dosages used in clinical trials for different drugs, a standardized comparison between them is necessary.

Methods

This study enrolled participants in phase II and III trials of innovative targeted drugs for MG. The primary outcome was the change in Quantitative Myasthenia Gravis score (MG-QMG) from baseline. The efficacy of all drugs at four time points was separately analyzed at four time points: initiation 1 week, initiation 4 weeks, maximized response, and post last dose 4 weeks. A network meta-analysis was conducted to compare the results of the different drugs.

Results

A total of 9 drugs, including Efgartigimod, Rozanolixizumab, Batoclimab, Eculizumab, Belimumab, Zilucoplan, Ravulizumab, Nipocalimab, Rituximab, derived from 12 studies were analyzed. At the initiation 1-week time point, three drugs exhibited significant improvement compared to the placebo effect: Efgartigimod, Zilucoplan, Rozanolixizumab. At the initiation 4-week time point, four drugs showed significant improvement compared to the placebo effect: Efgartigimod, Rozanolixizumab, Batoclimab, Zilucoplan. At the maximized response time point, six drugs achieved significant improvement compared to the placebo effect: Efgartigimod, Rozanolixizumab, Batoclimab, Eculizumab, Zilucoplan, Ravulizumab. At the post last dose 4-week point, all drugs statistically showed no significant difference from the placebo.

Conclusion

Although the MG subtypes were not consistent across trials, within the regimen design of each trial, neonatal Fc receptor inhibitors-represented by Efgartigimod, Rozanolixizumab, and Batoclimab-exhibited the most effective response rates when compared to complement and B-cell inhibitor drugs.

Efgartigimod treatment for generalized myasthenia gravis: a single-center case series of 16 patients

Background

Efgartigimod was approved in Japan in January 2022 for the treatment of generalized myasthenia gravis (gMG), regardless of antibody status. This case series describes a real-world experience in Japan of efgartigimod treatment for gMG patients with diverse backgrounds.

Methods

We retrospectively analyzed the medical records of 16 Japanese patients (11 females and five males, mean age 40.4 years) with gMG who received efgartigimod at the Kumamoto University Hospital between August 2022 and September 2023. The outcomes were Quantitative Myasthenia Gravis (QMG) responders (≥ 3 point reduction), IgG levels, and change in prednisolone dose, in the first cycle of efgartigimod.

Results

Fifteen patients completed one cycle of efgartigimod. Of the 14 patients for whom QMG scores were obtained, 10 patients were QMG responders. Four of the five patients with Myasthenia Gravis Foundation of America class V were QMG responders. Improvement in QMG after efgartigimod treatment was observed in one patient with myasthenic crisis and in one refractory patient who had unsuccessful eculizumab treatment. The mean reductions from baseline in IgG levels at weeks 1, 2, 3, and follow-up were 38.3, 56.1, 63.1, and 43.9%, respectively. A decrease in prednisolone dose was observed in seven patients. The most common adverse events were headache (three patients) and diarrhea (two patients). One patient discontinued efgartigimod treatment due to a treatment-related adverse event of rash.

Conclusion

Improvements in the outcomes of patients with gMG, including patients with severe gMG, myasthenic crisis, and refractory to anti-complementary therapy, were observed after the first cycle of efgartigimod treatment. Our real-world experience in Japan suggests the future possibilities for the treatment with efgartigimod for gMG with diverse backgrounds.

A real-life experience with eculizumab and efgartigimod in generalized myasthenia gravis patients

INTRODUCTION

Eculizumab, a complement active antibody, and efgartigimod, an Fc fragment that blocks neonatal Fc receptor, are both approved to treat generalized myasthenia gravis (gMG) patients. The objective of this study is to describe the clinical response to both treatments in a real-life setting.

METHODS

We collected baseline and follow-up clinical data using the Myasthenia Gravis-Activities of Daily Living (MG-ADL), and Quantitative Myasthenia Gravis (QMG). We included 63 patients, 32 treated with eculizumab and 31 with efgartigimod. Of the efgartigimod-treated patients, 22 were anti-acetylcholine receptor antibody-positive (AChR-Ab +) and 9 were AChR-Ab- (3 MuSK-Ab + and 6 seronegative).

RESULTS

Both treatments showed similar efficacy relative to the MG-ADL scale reduction (p = 0.237). Efgartigimod had a similar effect on both AChR-Ab + and AChR-Ab- (p = 0.280). Eculizumab was superior to efgartigimod relative to the QMG score reduction for the entire dataset (p = 0.003) and was more likely to achieve a clinical response at the QMG compared to efgartigimod (OR 1.373; p = 0.016). Steroid-sparing effect was higher for eculizumab than efgartigimod ( - 16.7 vs  - 5.2 mg of the baseline daily dose at follow-up; p = 0.001). Mean speed of prednisone reduction was  - 13.1 mg of the daily dose for each month of follow-up for eculizumab-treated patients and  - 3.2 for efgartigimod (p = 0.001). We found three serious events, all not related to treatment in the investigator's opinion. One eculizumab-treated patient experienced a severe pneumonia and died despite treatment.

CONCLUSIONS

Our study provides evidence that eculizumab and efgartigimod can be used in clinical practice to reduce disability in gMG patients. Eculizumab-treated patients had a higher QMG response and steroid sparing effect. Efgartigimod may offer a more flexible schedule due to its cyclical use, no need for vaccination, and efficacy in AChR-Ab- patients.

The safety and efficacy profile of eculizumab in myasthenic crisis: a prospective small case series

Eculizumab has improved recovery from ventilatory support in myasthenic crisis (MC) cases. However, the safety and efficacy profiles from prospective studies are still lacking. This study aimed to explore eculizumab's safety and efficacy in a prospective case series of patients with refractory MC. We followed a series of anti-acetylcholine receptor (AChR) antibody-positive myasthenia gravis (MG) patients who received eculizumab as an add-on therapy for 12 weeks during MC to facilitate the weaning process and reduced disease activity. Serum anti-AChR antibodies and peripheral immune molecules associated with the complement pathway were evaluated before and after eculizumab administration. Compared to the baseline Myasthenia Gravis Foundation of America (MGFA)-quantitative MG test (QMG) scores (22.25 ± 4.92) and MG-activities of daily living (MG-ADL; 18.25 ± 2.5) scores at crisis, improvements were observed from 4 weeks (14.5 ± 10.47 and 7.5 ± 7.59, respectively) through 12 weeks (7.5 ± 5.74 and 2.25 ± 3.86, respectively) post-treatment. Muscle strength consistently improved across ocular, bulbar, respiratory, and limb/gross domain groups. One patient died of cardiac failure at 16 weeks. Three cases remained in remission at 24 weeks, with a mean QMG score of 2.67 ± 2.89 and ADL score of 0.33 ± 0.58. No significant side effects were reported. Serum CH50 and soluble C5b-9 levels significantly declined, while there were no significant changes in serum anti-AChR antibody levels, C1q, C5a levels, or peripheral lymphocyte proportions. Eculizumab was well tolerated and showed efficacy in this case series. Large prospective cohort studies with extended follow-up periods are needed to further explore the safety and efficacy profile in real-world practice.

Efgartigimod as Rescue Medication in a Patient with Therapy-Refractory Myasthenic Crisis

Myasthenic crises (MC) are potentially life-threatening acute exacerbations of myasthenia gravis (MG) characterized by profound muscle weakness, bulbar symptoms, and potential for respiratory failure. Intravenous immunoglobulins (IVIG) and plasma exchange (PLEX) are conventional treatments for myasthenic exacerbations. Recently, new therapeutic options for generalized acetylcholine-receptor antibody positive (AchR+) MG were approved as an add-on therapy. They mainly consist of complement C5 inhibitors such as eculizumab and ravulizumab and neonatal Fc receptor antagonists such as efgartigimod with the approval of more options pending, e.g., zilucoplan and rozanolixizumab. More therapeutic options are in the pipeline. Although the data show a quick and reliable treatment response, these medications have not been studied for the therapy of myasthenic crisis. We present the case of a 57-year-old male with his first episode of generalized myasthenia gravis (MG) and positive acetylcholine-receptor antibodies (AchR+) who was transferred to our neurological intensive care unit with worsening generalized weakness, dysphagia, and respiratory distress. The crisis was triggered by pneumonia due to dysphagia. He was diagnosed with myasthenic crisis and treated with intravenous pyridostigmine, plasmapheresis (PLEX), and continued prednisone. Initial improvement was followed by deterioration, requiring readmission and additional PLEX. After a further decline, efgartigimod was administered, leading to significant improvement within 48 hours, as evidenced by reduced MG-ADL and QMG scores. The patient continued to improve and was stable enough for transfer to a rehabilitation facility. This case illustrates the potential of efgartigimod as a novel treatment for refractory myasthenic crises.

Novel uses of complement inhibitors in myasthenia gravis-Two case reports

INTRODUCTION/AIMS

Myasthenia gravis (MG) is a rare, life-threatening immune-related adverse effect (irAE) of immune checkpoint inhibitor (ICI) treatment. C5-complement inhibitors are effective treatments for acetylcholine receptor antibody (AChR ab) positive generalized MG. We describe the use of eculizumab/ravulizumab in two patients with MG receiving concomitant pembrolizumab.

METHODS

This was a retrospective review of two medical records.

RESULTS

Patient 1: An 80-year-old male with recurrent, non-muscle invasive transitional cell carcinoma of the bladder developed ICI-induced AChR ab positive MG (ICI-MG), myositis, and myocarditis 2 weeks after the first dose of pembrolizumab. Myositis responded to corticosteroids. MG responded to eculizumab, followed by ravulizumab. He died of metastatic cancer 8 months later. Patient 2: A 58-year-old male had refractory thymoma-associated AChR ab-positive MG, which responded to eculizumab. He developed metastatic Merkel cell cancer necessitating pembrolizumab. MG remained stable on eculizumab. He had no irAEs for 22 months, with positron emission tomographic resolution of cancer. He then developed mild, indolent retinal vasculitis, which responded to prednisone. Discontinuation of pembrolizumab for 5 months resulted in cancer recurrence; pembrolizumab was resumed with peri-infusion pulse prednisone. MG remained stable and he continues eculizumab.

DISCUSSION

In the first patient, eculizumab, followed by ravulizumab, improved ICI-MG. In the second patient, eculizumab treatment may have had a prophylactic effect on the development of ICI-induced irAEs. The effect of complement inhibition on cancer outcomes of ICI therapy is unknown. A possible biologic basis for complement inhibitors in reducing irAEs of ICI, especially in the presence of underlying autoimmune disease, merits evaluation.

Myasthenia gravis: the changing treatment landscape in the era of molecular therapies

Myasthenia gravis (MG) is an autoimmune disorder that affects the neuromuscular junction, leading to muscle weakness and fatigue. MG is caused by antibodies against the acetylcholine receptor (AChR), the muscle-specific kinase (MuSK) or other AChR-related proteins that are expressed in the postsynaptic muscle membrane. The standard therapeutic approach for MG has relied on acetylcholinesterase inhibitors, corticosteroids and immunosuppressants, which have shown good efficacy in improving MG-related symptoms in most people with the disease; however, these therapies can carry a considerable burden of long-term adverse effects. Moreover, up to 15% of individuals with MG exhibit limited or no response to these standard therapies. The emergence of molecular therapies, including monoclonal antibodies, B cell-depleting agents and chimeric antigen receptor T cell-based therapies, has the potential to revolutionize the MG treatment landscape. This Review provides a comprehensive overview of the progress achieved in molecular therapies for MG associated with AChR antibodies and MuSK antibodies, elucidating both the challenges and the opportunities these therapies present to the field. The latest developments in MG treatment are described, exploring the potential for personalized medicine approaches.

Ravulizumab in Myasthenia Gravis: A Review of the Current Evidence

The terminal complement C5 inhibitor ravulizumab was engineered from the humanized monoclonal antibody eculizumab to have an extended half-life and duration of action. It binds to human terminal complement protein C5, inhibiting its cleavage into C5a and C5b, thus preventing the cascade of events that lead to architectural destruction of the postsynaptic neuromuscular junction membrane by the membrane attack complex, and consequent muscle weakness in patients with anti-acetylcholine receptor (AChR) antibody-positive generalized myasthenia gravis (gMG). The 26-week randomized, placebo-controlled period (RCP) of the phase 3 CHAMPION MG study demonstrated the rapid efficacy of ravulizumab in reducing MG symptoms. Weight-based dosing of ravulizumab every 8 weeks provided sustained efficacy, in terms of patient-reported (Myasthenia Gravis-Activities of Daily Living) and clinician-reported (Quantitative Myasthenia Gravis) endpoints in patients with anti-AChR antibody-positive gMG. Pharmacokinetic and pharmacodynamic analyses showed therapeutic serum ravulizumab concentrations (>175 µg/mL) were achieved immediately after the first dose and were maintained throughout 26 weeks, irrespective of patient body weight; inhibition of serum free C5 was immediate, complete (<0.5 μg/mL), and sustained in all patients. Interim results from the open-label extension (OLE) showed that after 60 weeks, efficacy was maintained in patients continuing on ravulizumab. Rapid and sustained improvements in efficacy, similar to those seen in patients initiating ravulizumab in the RCP, were observed after initiation of ravulizumab treatment in patients who switched from placebo in the RCP to ravulizumab in the OLE. The findings from the RCP and OLE support ravulizumab's favorable safety profile. In conclusion, ravulizumab has a simple weight-based administration and long dosing interval. Its targeted mechanism of action without generalized immunosuppression is reflected in its rapid onset of symptom improvement, sustained efficacy and good safety profile in the treatment of patients with anti-AChR antibody-positive gMG.