By Amy Norton
THURSDAY, April 20, 2017 (HealthDay News) -- An experimental immune-system therapy appears safe for people with progressive forms of multiple sclerosis. And it may ease symptoms in some, a preliminary study suggests.
The findings are based on just six patients, and the Australian researchers stressed that a lot of work still lies ahead.
But they were encouraged that this new approach to MS had no major side effects. In addition, three of the six patients showed symptom improvements, including reduced fatigue and better mobility.
It's not clear, however, what to make of those improvements, said Bruce Bebo, executive vice president of research for the National Multiple Sclerosis Society.
The study was a "phase 1" trial, meaning it was designed only to test the therapy's safety.
"Based on this very preliminary study, the therapy appears safe," said Bebo, who was not involved in the research.
"But I'd be even more cautious in drawing any conclusions about the clinical improvements," he stressed.
Larger, rigorous clinical trials are needed to show whether the treatment truly works, Bebo said.
Multiple sclerosis is caused by a misguided immune system attack on the protective sheath around nerve fibers in the spine and brain. Depending on where the damage occurs, symptoms can include vision problems, muscle weakness, numbness and difficulty with balance and coordination.
Most people with MS are initially diagnosed with the "relapsing-remitting" form, which means that symptoms flare up for a time and then ease.
The new study involved patients with progressive MS, where the disease steadily worsens without periods of recovery.
Most had the "secondary" progressive form -- which means they initially had relapsing-remitting MS, but it worsened. One patient had progressive MS from the start, which is known as "primary" progressive MS.
The patients agreed to try a treatment never studied in MS, said study co-author Rajiv Khanna, of the QIMR Berghofer Medical Research Institute in Brisbane, Australia.
The approach is known as "adoptive" immunotherapy, where a patient's own immune system T cells are genetically tweaked to fight an enemy -- such as cancer cells.
Khanna's team took samples of the MS patients' T cells, then altered the cells to boost their ability to recognize and attack the Epstein-Barr virus. Those T cells were infused back into the patients' blood, at gradually escalating doses over six weeks.
Epstein-Barr is a common virus that infects most people at some point. But researchers suspect it plays a role in MS in some people.
According to Khanna, there is also evidence that MS progression correlates with Epstein-Barr "activation" in the body. The aim of the T-cell therapy is to "clear out" B cells -- another type of immune system cell -- that are infected with Epstein-Barr.
Over six months, the researchers said, none of the patients suffered serious side effects from the treatment.
In addition, three showed symptom improvements within two to eight weeks of their first T-cell infusion.
The findings are scheduled for presentation at the annual meeting of the American Academy of Neurology, April 22-28, in Boston.
The biology behind the T-cell therapy is not fully clear, Bebo said. Although Epstein-Barr is suspected as one factor in driving the initial development of MS, even that is not established, he said.
On the other hand, there is evidence that B cells drive inflammation in MS, Bebo said.
In fact, a new MS drug approved just last month works by targeting B cells, he noted.
That drug, called Ocrevus (ocrelizumab), is the first drug ever approved for primary progressive MS in the United States. It can also be used for the relapsing-remitting form.
Bebo said he suspects that if the experimental T-cell therapy has benefits in MS, it might be because it clears out B cells.
Even if the approach proves effective, there are practical hurdles in delivering a therapy like that, Bebo pointed out.
Khanna said his team is collaborating with a U.S. biotech company to see if the treatment process can be refined -- by creating "off-the-shelf" versions of Epstein-Barr-fighting T cells, for example.
Bebo emphasized the bigger picture: The new drug ocrelizumab was just approved and other treatments are in the pipeline.
"This is one of many approaches being tested," Bebo said. "We're learning more about MS progression all the time. So the future looks bright."
Study results presented at meetings are usually considered preliminary until published in a peer-reviewed medical journal.