Cancer Drug May Also Treat Chronic Fatigue Syndrome
Rituximab Reduced Fatigue in 67% of Patients in Study
By Brenda Goodman, MA
WebMD Health News
Oct. 19, 2011 -- Researchers in Norway say they've been able to treat
symptoms of chronic fatigue syndrome by giving patients a biologic
drug that affects the immune system.
The drug, rituximab (Rituxan), works by depleting immune cells called
B-cells. It is FDA approved to treat non-Hodgkin's lymphoma, chronic
lymphocytic leukemia, rheumatoid arthritis, and two kinds of
For the study, researchers recruited 30 people with chronic fatigue
syndrome (CFS). Half got two infusions of rituximab given two weeks
apart. The other half got infusions of saline solution as a placebo.
Ten patients in the rituximab group (67%) and two patients in the
placebo group (13%) saw at least moderate reductions in fatigue.
In most of the patients, improvements were transient and faded within
eight to 44 weeks.
But three patients, two in the rituximab group and one that got the
placebo, continue to be symptom free 2 1/2 years after their
treatments. Those three patients have all returned to full-time jobs,
The study is published in the journal PLoS One.
"Our thought is that in fact CFS is an autoimmune disease in most
patients," says study researcher Olav Mella, MD, PhD, an oncologist at
Haukeland University Hospital in Bergen, Norway.
Mella and his colleague, Oystein Fluge, MD, PhD, say they accidentally
discovered that rituximab might help chronic fatigue syndrome after
they used it to treat three patients who suffered from both CFS and
non-Hodgkin's lymphoma. All three patients reported significant
improvements in fatigue after rituximab infusions. They eventually
relapsed and were given more doses of rituximab. All three again had
improvements in their CFS, though those eventually faded.
Their cases were reported in BioMedCentral Neurology in 2009.
Is Chronic Fatigue Syndrome an Autoimmune Disease?
Researchers say they aren't sure why the drug is working.
"We cannot know for sure, but what we see is that there's a delay from
the rapid B-cell depletion after rituximab treatment to the clinical
response. The delay can be from three to perhaps eight months before
the response is thought to occur," says Fluge, who is an oncologist
and medical physicist at Haukeland Hospital.
B-cells are part of the immune system. They roam the body in
relatively small numbers searching for foreign invaders. When a B-cell
finds one, it springs into action, becoming an infection-fighting
In some diseases, like leukemia, B-cells may go haywire and cause
cancer. In rheumatoid arthritis, B-cells may attack the body's own
In CFS, however, it's unclear why killing off B-cells might help.
One theory, held by researchers who believe CFS may be caused by an
infection, suggests that retroviruses may hide out in dormant B-cells,
only becoming active when the cell is triggered and rapidly
But Fluge thinks if that's the case, patients would see quicker
improvements after taking the rituximab.
"We think what we see could be best explained with an autoimmune
mechanism and gradual elimination of auto-antibodies," he says.
Other, more circumstantial evidence supports the idea that CFS may be
an autoimmune disease.
Like other autoimmune conditions, it tends to be much more common in
women than in men, for example. Many people report getting CFS after a
bout with triggering illness. The risk of getting chronic fatigue
appears be similar to the risk for getting other kinds of immune
More Research Needed
Despite the positive results of the study, researchers stressed that
it was far too early for people with chronic fatigue to seek treatment
"For the time being, this is a clinical trial. It is not for routine
use. We need at least one more large study, partly here and partly
somewhere else, to confirm the results," Mella says.
Rituximab is expensive. A single course of treatment for cancer can
cost more than $20,000. Rarely, fatal reactions have been reported
after infusions of the drug, although no significant adverse events
were reported in the current study.
"The most exciting news from the study is the possibility of
disease-modifying treatment for at least some people with CFS," Kim
McCleary, president and chief executive officer of the CFIDS
Association of America, says in an email. "This study also provides
support for other possible approaches to repair immune abnormalities
that have been identified in CFS patients."