Myasthenia Gravis (MG)
Conditions
Brief summary
Myasthenia Gravis (MG) is a chronic autoimmune disease mediated by pathogenic antibodies. Approximately 10%-15% of patients present with refractory status, defined as having an inadequate response to existing therapies or an inability to tolerate the side effects of the medication, highlighting an urgent need for the development of more targeted innovative therapies. Talquetamab is a bispecific antibody that targets G Protein-Coupled Receptor Class C Group 5 Member D (GPRC5D) and the Cluster of Differentiation 3 (CD3) molecule on the surface of T cells, thereby inducing T cells to precisely eliminate GPRC5D-positive cells. This study will conduct an exploratory case series to investigate the efficacy and safety of Talquetamab in refractory MG.
Interventions
DRUGTalquetamab
Eligible patients will receive the drug via subcutaneous injection on Days 1, 3, and 5, respectively. The dose will be determined based on body weight measured before administration, according to the following table. A total of 3 doses will be administered. Administration Day and Dose: 0.01 mg/kg in Day 1; 0.06 mg/kg in Day 3; 0.4 mg/kg in Day 5.
Sponsors
First Affiliated Hospital of Chongqing Medical University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
* The patient must sign the informed consent form for participation in the study and agree to comply with the study procedures. * Age 18-70 years. * Must meet the clinical diagnostic criteria for MG, defined as presenting with a typical pattern of weakness (predominantly affecting proximal muscles, fatiguability, fluctuating severity, worse with prolonged effort and better after rest) and meeting any one of the following three conditions: documented history of abnormal neuromuscular transmission confirmed by single-fiber electromyography or repetitive nerve stimulation; documented history of a positive neostigmine test; or improvement in MG signs following oral administration of an acetylcholinesterase inhibitor. Additionally, the Myasthenia Gravis Foundation of America (MGFA) clinical classification must be II-IV, and the patient must be positive for anti-AChR antibodies. * Must meet the definition of "refractory myasthenia gravis" according to the Chinese Guidelines for the Diagnosis and Treatment of Myasthenia Gravis (2025 Edition): defined as having a suboptimal response to conventional immunotherapeutic drugs, intolerance to or having contraindications for adverse drug reactions, or experiencing frequent disease relapses requiring regular rescue therapy, making it difficult to achieve treatment goals. * Myasthenia Gravis Activities of Daily Living (MG-ADL, Appendix 1) score ≥6, with \>50% of the score derived from non-ocular items. * Quantitative Myasthenia Gravis (QMG) score (Appendix 2) ≥8, with \>50% of the score derived from non-ocular items. * The dosage of pyridostigmine bromide must be stable for at least 1 week prior to the treatment period.
Exclusion criteria
* Patients who have had their glucocorticoid dose adjusted, or who have received immunoglobulins, plasma exchange, neonatal Fc receptor inhibitors, or complement inhibitors within ≤4 weeks. * Patients who have undergone thymectomy, received B-cell depletion therapy, or had their dose of non-steroidal immunosuppressants (such as azathioprine, tacrolimus, mycophenolate mofetil, cyclophosphamide, etc.) adjusted within ≤3 months. * Patients who have participated in any interventional clinical trial or received investigational treatment within ≤3 months, or within 5 half-lives of the received investigational drug (whichever is longer). * Patients with concurrent severe liver, kidney, cardiac, pulmonary, or coagulation dysfunction. * Patients with concurrent chronic infections such as Human Immunodeficiency Virus, Hepatitis B Virus, Hepatitis C Virus, or Mycobacterium tuberculosis.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| MG-ADL score | baseline, and 1-6 months | Full scale title: Myasthenia Gravis Activities of Daily Living Profile (MG-ADL) Score range: 0-24 A higher score means worse outcomes (greater symptom severity and more impairment in daily functioning). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| QMG score | baseline and 1-6 months | Full scale title: Quantitative Myasthenia Gravis Score (QMG), also referred to as the Quantitative Myasthenia Gravis Scale . Score range:0-39 A higher score means worse outcomes (more severe disease and greater weakness). Conversely, a lower score indicates milder disease or better symptom control . |
Outcome results
None listed