The Food and Drug Administration (FDA) has given people with multiple sclerosis some hope.

On Wednesday, FDA officials announced the agency has approved a new drug to treat adults who have the relapsing form of multiple sclerosis (MS) as well as primary progressive MS (PPMS).

It's the first drug approved for treatment of PPMS.

The drug, Ocrevus (ocrelizumab), is an intravenous infusion given by a medical professional.

The approval is especially good news for those with progressive types of MS who have not found a drug that has worked to reduce flares, improve symptoms, or slow disease progression.

According to the National Multiple Sclerosis Society, 2.3 million people worldwide are living with the disease.

Now, for the first time, people with PPMS may benefit from what officials at Roche Pharmaceuticals have called a medical breakthrough.

In a large phase III trial, Ocrevus was shown to significantly slow the progression of physical disability in people with PPMS. It was also successful in two large studies at reducing attacks in people with relapsing MS (RMS), according to Roche.

In December 2016, the FDA delayed approval for Ocrevus until this spring due to manufacturing issues.

Read more: Are biomarkers the future of treatment of multiple sclerosis? »

How the drug works

MS hits everyone differently, with an array of symptoms and possible progressions.

Its unique characteristics make finding remedies a challenge.

Some people with MS may respond to one of the injectable disease modifying drugs (DMD) on the market. For others, one of the new oral drugs might work better for limiting attacks, lessening symptoms, and slowing progression of the disease.

But there are those people who have tried everything approved by the FDA and still have not found a therapy that slows the progress of the disease and prevents their disabilities from getting worse.

While several drugs are touted as being effective for RRMS, there had been no approved drugs specifically for PPMS.

Ocrevus is designed to target the B cells that are responsible for myelin sheath damage and repair.

These CD20-positive B cells are a type of immune cell thought to be a key contributor to myelin (nerve cell insulation and support) and axonal (nerve cell) damage, which can result in disability in people with MS.

B cells are part of the immune system and so called because they develop in bone marrow and produce antibodies. T cells, the other white blood cells in the immune system, are developed in the thymus gland.

Myelin is damaged by certain activation of T cells, which may be affected by B cells.

“I’ve spent nearly the last 25 years of my career in both research labs and clinical development trying to find a novel treatment for MS. Like nearly all other researchers I have been focused on broadly immunomodulatory treatments or T cell directed treatments,” Dr. Hideki Garren, Ph.D., group medical director and clinical science leader at Genentech, told Healthline.

Genentech, part of the Roche Group, developed Ocrevus.

“What’s new and exciting about Ocrevus is that it is directed to only one component of the immune system, the B cell, which should provide efficacy and safety advantages,” Garren said.

Read more: Vitamin D may help prevent, treat multiple sclerosis »

Waiting and hoping

Genentech has an ongoing study to test Ocrevus with various biomarkers that could determine the success of the drug on the patient prior to taking it.

The FDA extension was the result of the submission of additional data by Genentech regarding the commercial manufacturing process of Ocrevus. The extension is not related to the efficacy or safety of Ocrevus, Genentech said in a statement.

Officials at the National Multiple Sclerosis Society are optimistic about the new drug.

“It will be a breakthrough for people living with primary progressive MS, who have waited so long for an effective disease modifying therapy,” said Dr. Bruce Bebo, the organization’s executive vice president of research, in a statement. “We hope that this success will encourage others to focus more resources into the research and development of treatments for progressive forms of MS.”

Many patients are also eagerly awaiting the medication.

“Hope stays alive,” said MS patient and blogger, Erika Lopez, who has now tried every feasible option for her progressive MS.

“Just make it stop. Make the progression stop,” she told Healthline.

Editor’s Note: Caroline Craven is a patient expert living with MS. Her award winning blog is, and she can be found @thegirlwithms.

Read more: Marijuana touted as a possible treatment for multiple sclerosis »