The full press release auto-translated. Some line breaks added.
—————
About the investigator-initiated clinical trial targeting myalgic encephalomyelitis/chronic fatigue syndrome
The National Center of Neurology and Psychiatry (Kodaira City, President: Kazuyuki Nakagome, hereinafter referred to as NCNP) will begin investigator-initiated clinical trials of the drug rituximab (recombinant) (anti-CD20 monoclonal antibody, hereinafter referred to as rituximab), which targets B cells, in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) who are outpatients at NCNP Hospital. Rituximab is a mouse-human chimeric monoclonal antibody that targets the CD20 antigen expressed by B cells, and due to its efficacy in depleting B cells, it is covered by insurance for malignant tumors (malignant lymphoma) and various immune diseases (vasculitis, scleroderma, etc.) involving B cells.
Development Background
ME/CFS is an intractable disease that develops due to viral infections and other factors, and can lead to severe exhaustion and sleep disorders that leave patients bedridden or make it difficult to perform the physical activities necessary for daily social life. Although symptoms can improve to a certain extent, patients face many difficulties before returning to society, as symptoms can rapidly worsen due to stressful lifestyles and physical and mental stress.
In addition, because abnormalities cannot be detected by general blood tests or imaging tests, awareness of the disease is low in the medical field or in the general public, and many patients and their families are in extremely difficult situations.
The NCNP Neuroscience Institute Immunology Research Department has been carrying out a project to build a medical network for ME/CFS (AMED Yamamura group; 2018-2020) and a research project to develop blood diagnostic methods (AMED Sato group; 2019-2021), and has published results that lead to understanding the pathology of ME/CFS and the development of treatment strategies1 )-4) .
In particular, they have been actively researching B cells, a type of immune cell, and autoantibodies, and have confirmed that autoantibodies against autonomic nervous system molecules (such as β2 adrenergic receptors) are detected in more than 30% of ME/CFS patients, and have further demonstrated that the increase in autonomic nervous system receptor-reactive autoantibodies is related to abnormalities in the neural network in the brain.2 )
In parallel ,
detailed analysis of the antigen receptor genes of B cells suggested that ME/CFS patients are exposed to specific antigens (such as viruses) and are in a state where the immune system is strongly stimulated.3 ) Based on the above, ME/CFS is a neuroimmune disease (a disease with problems that span both the nervous and immune systems), and it is thought that there is a possibility that the indications of drugs used for neuroimmune diseases may be expanded. In response to this, European researchers have published a series of papers supporting the idea that ME/CFS is an autoimmune disease.
Currently, B cells are an important research or treatment target in neuroimmune and autoimmune diseases, and a Norwegian research team conducted a clinical trial in which ME/CFS patients were administered the anti-CD20 antibody rituximab, which removes B cells.
This clinical trial was planned based on the clinical observation that when rituximab was administered to patients with malignant lymphoma and ME/CFS for the purpose of treating malignant lymphoma, ME/CFS also improved. In a Phase II trial, efficacy was confirmed in 18 out of 29 patients. In a Phase III multicenter placebo-controlled trial, efficacy could not be demonstrated, but at least some patients were shown to respond to treatment. ME/CFS is expected to include a diverse patient population, and it was suggested that rituximab may be effective in specific patient groups defined by biomarkers.
Development details
This investigator-initiated clinical trial will exploratory compare the efficacy and safety of rituximab against ME/CFS symptoms in 30 ME/CFS patients attending NCNP Hospital using a placebo-controlled double-blind method (primary evaluation period 24 weeks). In the subsequent secondary evaluation period (24 weeks), patients who received rituximab in the primary evaluation period (hereinafter referred to as the rituximab-first administration group) will be administered a placebo, and the onset and duration of the effects of rituximab will be exploratory examined throughout the entire evaluation period (48 weeks).
In addition, patients who received a placebo in the primary evaluation period (hereinafter referred to as the placebo-first administration group) will be administered rituximab in the secondary evaluation period (24 weeks), and changes in evaluation items before and after switching from placebo to rituximab within the same patients will be exploratory examined.
In order to identify the rituximab effective group, an exploratory study will be conducted by adding ME/CFS severity classification based on the Performance Status score defined in Japan for symptom evaluation to the evaluation items used in the Norwegian clinical trial, as well as immune biomarkers that may be related to efficacy. In addition, this investigator-initiated clinical trial is expected to make it easier to detect clinical improvement/deterioration than previous clinical trials by using techniques such as having participants record their daily symptoms using an app stored on their smartphones.
Future developments
It is expected that the results of this investigator-initiated clinical trial will advance our understanding of the pathology of ME/CFS and the development of biomarkers, leading to the development of new treatments that target B cells.