Nearly a century after James Dawson first described the inflammation and lesions characteristic of multiple sclerosis (MS), researchers are finally honing in on what drives its progression.

In the first of a series of papers to be published in The Lancet, researchers are exploring the progressive forms of the disease.

While the cause of MS remains a mystery, scientists have made strides in treating it. Most of the progress has revolved around treating relapsing-remitting MS (RRMS).

The inflammation driving the ebb and flow of RRMS has given scientists a target for developing therapies to control the disease. This has resulted in a current arsenal of 12 FDA-approved treatments for RRMS.

With RRMS effectively held at bay and technological advances aiding researchers in their quest to learn more, the focus is turning toward progressive MS.

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RRMS vs. Progressive MS

What sets progressive forms apart, making them difficult to treat is that this immune response “becomes in part hidden within the brain behind a closed or repaired blood brain barrier,” said the paper’s lead author, Professor Hans Lassmann, founding director of the Center for Brain Research, Medical University of Vienna, in an interview with Healthline. “Thus, many of our current drugs do not reach such an inflammatory process.”

Although some people seem to start out with progressive MS, “We think that all patients, even those with primary-progressive MS (PPMS), have silent disease long before they enter the progressive phase,” said Lassmann.

Factors for whether they relapse can depend on the severity of the disease or even location of the lesions. Damage to some regions of the brain might not be detectable with the current clinical tools.

Defining the differences between RRMS and progressive MS is key to developing effective treatments. Lassmann points out, “There is still inflammation in the brain of patients, even when they have entered the progressive phase.”

Learn More: The 4 Types of MS »

What’s on the Horizon?

According to Dr. Bruce Bebo, executive vice president of research at the National Multiple Sclerosis Society, the landscape may soon be changing for people living with progressive forms of the disease.

He noted there are 40 ongoing clinical trials registered with the Food and Drug Administration that are testing approaches for the treatment of progressive MS.

“Some of these trials are testing new agents and others are testing agents approved for other diseases,” Bebo told Healthline. “One example is a trial being conducted by the Cleveland Clinic of a repurposed therapy called ibudilast in progressive MS that is sponsored by the National MS Society and the National Institutes of Health. We are also funding a clinical trial to determine whether a therapy for epilepsy can prevent nerve fiber damage in optic neuritis, often an early stage of MS.”

Researchers are learning the extent to which they may be able to restore function in people with MS, according to Bebo.

“Just a few short years ago, there was little belief that nervous system repair was even possible,” he said. “In part through pioneering funding in this area by the National MS Society, potential cell therapies and myelin repair strategies are now approaching or actually in clinical trials in people who are living with MS.”

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Progressive MS Alliance

Bebo shared his excitement with the International Progressive MS Alliance “to catalyze discoveries leading to treatments for progressive forms of MS.”

“The National MS Society is a managing member and leader in this expanding alliance of organizations from around the world,” explained Bebo. “The Alliance is urgently working to connect resources and experts to find the answers that will lead to new treatments for progressive MS.”

He noted the Alliance recently awarded its first 22 research grants, and has recently solicited proposals to establish collaborative research networks.

“The goal of the Alliance is to remove barriers to developing treatments for progressive MS,” he said. “It’s the start of an ambitious program that will invest at least 30 million dollars over six years.”

To learn more about what’s new in progressive MS research, watch a webcast on the Society’s website.

Get the Basics: The Facts About Multiple Sclerosis »