The First Approved Treatment for PPMS
Almost 200,000 people in the United States alone are diagnosed with multiple sclerosis, or MS, per year. A brutal disease, MS can cause irreparable physical damage and even death at progressed stages. There are different types of this disease, including primary-progressive MS (PPMS), a disease which until now had no approved treatments. This condition attacks the central nervous system, begins as pain or fatigue, and progresses into disability or death.
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How does Multiple Sclerosis affect the Central Nervous System?
To understand this, we must first understand the basic anatomy of a neuron. A neuron is not like a normal cell, even though it has all the organelles of any other eukaryotic cell. Neurons have distinct features such as dendrites, an axon, and axon terminals. Neurons serve the function of sending and receiving signals, which are received from the dendrite branches and sent through the axon to the axon-terminal. At the axon-terminal, there are synapses between one cell and another. The axon is a long pathway, surrounded by something called the myelin sheath, which allows signals to travel through the axon quickly and controls ion concentrations in the cell.
MS is a condition where the immune system attacks the myelin sheath, compromising a neuron's ability to send a signal. This is incredibly dangerous, since, on a large scale, this could compromise the entire nervous system in some areas, which causes disability.
What is Primary-Progressive Multiple Sclerosis (PPMS)?
PPMS is a rare type of MS, affecting around 15% of multiple sclerosis patients. The remaining around 85% of other patients have RRMS, or Relapsing-Remitting Multiple Sclerosis. These two types attack the nervous system in the same way, but are different in intensity. RRMS is called relapsing-remitting because the symptoms have flares, which die down and increase at random times. The dangerous part of PPMS is that the symptoms progress worse and worse, with no flare-ups or relapses.
What treatments are there for PPMS?
Until a few years ago, there were almost no treatments for PPMS. There were some experimental drugs, but none of which were shown to have any positive affects on the progression of this disease. The common care for this condition was rehabilitation, therapy, and overall symptom management. However, a few years ago, a revolutionary new treatment called Ocrevus was approved by the FDA (Food and Drug Administration) as a viable care option for PPMS.
How does Ocrevus work?
Ocrevus is the brand name for ocrelizumab, a monoclonal antibody. This treatment is administered through intravenous injections (IV). Our immune system is made primarily of T-Cells and B-Cells. These cells malfunction in MS, and become detrimental to the nervous system. Before Ocrevus, T-Cells were thought to be the primary perpetrators of this disease. Most medications targeted mainly T-Cells. However, Ocrevus also targeted B-Cells, but only B-Cells with a certain receptor. This receptor is called CD20, and it allows the cell to receive chemical signals from elsewhere in the body. This drug binds to cells with CD20 and bursts them, drastically reducing the effects of PPMS. Patients who used Ocrevus report higher function and fewer symptoms of disability.
This treatment marks a very important milestone in the study of multiple sclerosis and other autoimmune diseases as well, and was the first and only PPMS treatment to be approved by the FDA.