Multiple sclerosis (MS) is a chronic autoimmune condition. It occurs when the body starts to attack itself. Current medications and treatments are focused on the relapsing types of MS and not on primary-progressive MS (PPMS). Clinical trials are constantly being held to help better understand PPMS and to find new, effective treatments.

What are the different types of MS?

The four main types of MS are:

  • clinically isolated syndrome (CIS)
  • relapsing-remitting MS (RRMS)
  • primary-progressive MS (PPMS)
  • secondary-progressive MS (SPMS)

These MS types were created to help medical researchers categorize participants of clinical trials with comparable disease development. This helps researchers evaluate how effective and safe a certain medication or treatment is without using a large number of participants.

What is PPMS?

PPMS is the rarest form of MS, affecting only 10 percent of all people diagnosed with MS. Most types of MS occur when the immune system attacks the myelin sheath. The myelin sheath is a fatty, protective substance that surrounds nerves in the spinal cord and brain. When this substance is attacked, it causes inflammation. PPMS includes nerve damage and scar tissue on the damaged areas. This disease disturbs the process of nerve communication, causing an unpredictable pattern of symptoms and disease progression.

PPMS treatment

Treatment of PPMS is more difficult than RRMS and includes the use of immunosuppressive therapies. These therapies offer only temporary help. They can only be safely used continuously for a few months to a year at a time.

While the FDA has approved over a dozen medications for relapsing MS types, not all are for progressive types. This is because disease-modifying drugs (DMDs) are given continuously and often have intolerable side effects. Actively demyelinating lesions and nerve damage can also be found in patients with PPMS. These lesions are highly inflammatory and may cause damage to the myelin sheath. It’s unclear at this time whether medications that reduce inflammation can slow progressive forms of MS.

PPMS clinical trials

A key priority for researchers is learning more about progressive forms of MS. New drugs must go through rigorous clinical testing before the FDA approves them. Most clinical trials last for 2 to 3 years. However, because the research on PPMS is limited, longer trials are needed for this type of MS.

More trials are being done on the relapsing types of MS because it’s easier to judge the medication’s effectiveness on the relapses.

Most drug manufacturers can’t afford to host lengthy clinical trials. This is why only a handful of them have been done on PPMS.

The following PPMS clinical trials are currently underway. For a complete list of MS clinical trials, see the National MS Society website.

Idebenone (Catena/Raxone)

The National Institute of Neurological Disorders and Stroke is inviting some participants to a phase II clinical trial. The trial will evaluate the drug Idebenone’s effect on patients with PPMS. Researchers are giving patients either the drug or a placebo throughout the course of one year. No conclusive results on the drug’s effectiveness have been found so far.

Ocrevus (Ocrelizumab)

Swiss drug maker Roche has reported positive results of phase II and III clinical trials, called ORATORIO, of PPMS patients in January 2016. This is the first drug to show effective results for both progressive and relapsing types of MS in a clinical trial. The drug was able to stop the progression of symptoms in PPMS by around 25 percent. The FDA approved ocrelizumab as a treatment for both relapsing and primary progressive MS in March 2017. Phase III clinical trials compare the safety and effectiveness of the new treatment against the current standard treatment. While it has been approved for use in the United States, the trials continue while waiting for approval in Europe.


Teva Pharmaceutical Industries is sponsoring a study in an effort to establish proof for potential treatment with laquinimod in patients with PPMS.


The University College of Dublin is recruiting participants to examine the effect of treatment with fampridine in patients with secondary-progressive MS (SPMS) or primary-progressive MS (PPMS) with upper limb dysfunction.

PPMS research

The National MS Society is promoting ongoing research to find the differences between PPMS and other MS types. The goal is to create a successful treatment for PPMS. Hospitals, universities, and other organizations all over the United States are continuously working to learn more about PPMS and MS in general. Ask your healthcare provider about the latest clinical trials and research that could benefit you.