Influence of Minimally Invasive Thymectomy on the Subsequent Clinical Course of Myasthenia Gravis

Study Overview
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Brief Summary
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The aim of this study is to investigate whether minimally invasive thymectomy achieves comparable efficacy and safety results compared to open thymectomy in patients with myasthenia gravis. The planned investigation is a multicenter observational study based on retrospective (present patient data) and prospective data (questionable outcome data). Primary hypothesis: Minimally invasive thymectomy is not inferior to open thymectomy in terms of efficacy and safety (non-inferiority study).

Detailed Description
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Based on large cohort studies of the last decades, the thymectomy has become a central component of the immunomodulating therapy in MG patients without thymoma detection. Because randomized studies were missing, remained a residual uncertainty on the importance of Thymectomy. In the study Randomized Trial of Thymectomy in Myasthenia Gravis (MGTX-study) published 2016 the effectiveness of thymectomy by patients without thymoma detection has been indisputable confirmed. A significant improvement of the patient's complaints and the reduction of the immunosuppressive drugs were particularly evident by early onset MG (EOMG) two to three years after performing a complete resection of the thymic tissue. While the MGTX study (with an open operative procedure) was being done, the minimally-invasive thymectomy has gained more and more acceptance. From a surgical point of view, the minimally invasive thoracoscopic procedure represents a gentler alternative. According to the momentaneous clinical-scientific point of view, further studies are necessary to compare both procedures. Furthermore, the MGTX study included only patients with generalized MG and positive anti-Acetylcholine Receptor (AChR)-antibodies, who were younger than 65 years, so that the relevance of thymectomy in other important subgroups, such as late onset MG (LOMG), the ocular MG (OMG), as well as the patients without detected antibodies (seronegative MG patients), who represent about 10 % of whole population of MG patients, is still not clear.

Official Title
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Influence of Minimally Invasive Thymectomy on the Subsequent Clinical Course of Myasthenia Gravis

Conditions
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Myasthenia Gravis

Intervention / Treatment
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* Procedure: thymectomy (robotic-assisted thoracoscopic, minimally-invasive thymectomy)
* Procedure: thymectomy by means of median sternotomy (transsternal)
* Procedure: no thymectomy (control)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with Myasthenia Gravis Age ≥18 years Exclusion Criteria: a proper communication with the patient is not possible an informed consent could not be signed a patient reject a participation or requires breaking up

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Tmin-group<br>confirmed seropositive ocular or generalized MG [detection of antibodies (Abs) targeting the AChR, muscle-specific tyrosine kinase (MuSK) or Titin] or seronegative ocular or generalized MG age ≥ 18 years thymectomy ≥ three years | Procedure: thymectomy (robotic-assisted thoracoscopic, minimally-invasive thymectomy)<br>* preferring one unilateral access and placing three trocars between 3rd and 5th intercostal space in a triangular configuration, with a goal of an en bloc resection of all mediastinal tissue that could anatomically contain gross or microscopic thymus (or both).<br>|
| T0-group<br>confirmed seropositive ocular or generalized MG [detection of antibodies (Abs) targeting the AChR, muscle-specific tyrosine kinase (MuSK) or Titin] or seronegative ocular or generalized MG a very long disease history OR age ≥ 18 years rejecting a thymectomy or have contraindications for thymectomy | Procedure: no thymectomy (control)<br>* routine medical care<br>|
| MGTX-group (historical control group)<br>from MGTX-trial (Randomized Trial of Thymectomy in Myasthenia Gravis) | Procedure: thymectomy by means of median sternotomy (transsternal)<br>* with a goal of an en bloc resection of all mediastinal tissue that could anatomically contain gross or microscopic thymus (or both).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean daily prednisone dose |  | three years after thymectomy | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Myasthenia Gravis, Robotic-assisted minimally-invasive thymectomy, Mean daily prednisone dose