A new study has found that chronic fatigue syndrome (ME/CFS) patients treated with the anti-cancer drug Rituximab experienced significant relief from their symptoms. Based on the drug's mode of action this suggests immune system dysfunction, and possibly autoimmunity, are important in this debilitating illness.
Rituximab is tradtitionally used as a chemotherapy drug in the treatment of certain cancers. One of its actions is to deplete the number of B-lymphocytes in the body. Also known simply as B-cells, these white blood cells produced by the immune system are associated with allergies and some autoimmune diseases.
Norwegian researchers first noticed the beneficial effects of Rituximab when using the drug to treat a patient with Hodgkin's lymphoma, who also suffered from ME/CFS. While undergoing chemotherapy with Rituximab the patient reported siognificant relief from their chronic fatigue syndrome symptoms. The investigators reasoned that the effect could be mediated through B-lymphocyte depletion and decided to investigate further, culminating in a recent double-blind, placebo-controlled trial, the results of which are published in the journal PLoS ONE.
The study, carried out at the Haukeland University Hospital in Bergen, involved 30 ME/CFS patients who were randomised so that 15 received Rituximab treatment and the other 15 a placebo (saline solution). Both treatment and placebo were administered twice, two weeks apart, and participants' symptom response was monitored for 12 months.
Major or moderate overall response, defined as lasting improvements in self-reported Fatigue score during follow-up, was seen in 10 out of 15 patients (67%) in the Rituximab group and in only two out of 15 patients (13%) in the placebo group. In the participants who responded to Rituximab treatment, improvements in all ME/CFS were generally seen.
An important observation noted by the scientists was that improvements in symptoms in those given the drug were not seen until between two and seven months post-treatment, despite rapid depletion of B-lymphocytes in their blood.
The researchers conclude that, "the delay of clinical responses after the initial and rapid B-cell depletion suggests to us that CFS/ME, which is often preceded by an infection, may be a form of autoimmune disease in which B-cells are important". They add that their findings point to a new research direction for investigating the pathophysiology of the disease and potential treatments.
Unfortunately, the symptom improvements following Rituximab treatment in the study did not last. A different approach with "booster" treatments every three months is now being considered.
American ME/CFS expert Dr. Jacob Teitelbaum, M.D., commented that, "[I] consider this study to be very promising as an eventual treatment option — as well as being another study proving that CFS is a very real disease." He does however have reservations at present, pointing out that Rituximab is hugely expensive and that improvements seen in the study were in fact rather modest (24% improvement in vitality and 40% reduction in pain - at best).
Meanwhile, Dr. Charles Shepherd, the UK ME Association's medical adviser, told the BBC: "The results of this clinical trial are very encouraging news for people with ME. Firstly, they help to confirm that there is a significant abnormality in immune system function in this disease. Secondly, they indicate that altering the immune system response in ME could be an effective form of treatment for at least a subset of patients.
Both doctors agree that further research is now needed to confirm the study's findings and further test the effectiveness of Rituximab and similar drugs in ME/CFS.
Source: Fluge Ø Bruland O Risa K Storstein A Kristoffersen EK Sapkota D Næss H Dahl O Nyland H Mella O (2011) Benefit from B-Lymphocyte Depletion Using the Anti-CD20 Antibody Rituximab in Chronic Fatigue Syndrome. A Double-Blind and Placebo-Controlled Study. PLoS ONE 6(10): e26358