Therapeutic efficacy and immunoregulatory effect of Qiangji Jianli Capsule for patients with myasthenia gravis: Study protocol for a series of randomized, controlled N-of-1 trials

INTRODUCTION: Myasthenia gravis (MG) is an autoimmune disease in which antibodies directly target components of the neuromuscular junction, causing neuromuscular conduction damage that leads to muscle weakness. The current pharmaceutical treatment for MG is still not ideal to address the problems of disease progression, high recurrence rate, and drug side effects. Clinical observations suggest that traditional Chinese medicine (TCM) can strengthen immunity and improve symptoms of MG patients, delay the progression of the disease, reduce or even prevent the need for immunosuppressive therapy when used in combination with acetylcholinesterase inhibitors or low-dose prednisone, as well as improve the quality of life of patients. The Qiangji Jianli Capsule (QJC) is a combination of medicinal herbs which is used in traditional Chinese medicine. Since MG is a rare disorder, randomized controlled trials comparing large cohorts are difficult to conduct. Therefore, we proposed to aggregate data from a small series of N-of-1 trials to assess the effect of the Chinese medical prescription QJC, which strengthens the spleen and nourishes Qi, as an add-on treatment for MG with spleen and stomach Qi deficiency syndrome. METHODS AND ANALYSIS: Single-center, randomized, double-blind, multiple crossover N-of-1 studies will compare QJC versus placebo in 5 adult MG patients with spleen and stomach Qi deficiency syndrome. Patients will undergo 3 cycles of two 4-week intervention periods. According to the treatment schedule, patients will continue to be treated with pyridine bromide tablets, prednisone acetate, tablets and/or tacrolimus capsules throughout the entire trial. Each period consisting of 4-week oral add-on treatment with QJC will be compared with 4-week add-on treatment with a placebo. The primary endpoints are quantitative myasthenia gravis (QMG) test; measurement of the amount of T(reg) cells and cytokines such as interferon-γ (IFN-γ), interleukin-4 (IL-4), interleukin-17A (IL-17A), and transforming growth factor-β (TGF-β); and corticosteroid or immunosuppressive agent dosage. Secondary outcome measures: Clinical: Evaluation of the effect of TCM syndromes; MG-activities of daily living (MG-ADL) scales; adverse events. ETHICS AND DISSEMINATION: This study was approved by The First Affiliated Hospital of Guangzhou University of Chinese Medicine (GZUCM), No. ZYYECK[2019]038. The results will be published in a peer-reviewed publication. Regulatory stakeholders will comment on the suitability of the trial for market authorization and reimbursement purposes. Trial registration: Chinese Clinical Trial Register, ID: ChiCTR2000033516. Registered on 3 June 2020, http://www.chictr.org.cn/showprojen.aspx?proj=54618.