To understand how GILENYA affects the body, we need to start at the beginning.
Multiple sclerosis (MS) is an autoimmune disease that attacks the healthy tissues in the central nervous system (CNS). When MS attacks myelin—the covering that surrounds and protects the body's nerve fibers—nerve impulses are interrupted, causing MS symptoms.
See how GILENYA is thought to work
Research is still being done on which immune cells are mounting the attack, the factors that cause the attack, and the sites that appear to be attracted to the myelin to begin the destructive process. There are plenty of websites that provide a more thorough scientific description of this process (check out nmss.org, for example), but here's a quick snapshot on how cells called lymphocytes affect the immune system.
The immune system contains a network of lymph nodes, which are tiny glands containing immune cells called lymphocytes. Lymphocytes are normally good guys, but sometimes they can go rogue. This can mean they go after your CNS and cause problems.
While it's not exactly clear how GILENYA works, it is thought to keep lymphocytes from attacking your CNS by lowering the number of lymphocytes circulating in your blood.
Scientists believe that GILENYA is thought to work by keeping some lymphocytes locked up inside the lymph nodes.* If lymphocytes are prevented from reaching the CNS, there may be less inflammatory damage to the covering of the nerve fibers.
During GILENYA treatment, some lymphocytes are still circulating and available to do their job, watching out for intruders like viruses and bacteria.
If your health care professional decides to stop your GILENYA treatment for any reason, the "door" of the lymph node is opened up. Within a few days, the number of lymphocytes circulating in your blood increases, and then gradually returns to original levelsusually within 1 to 2 months.
GILENYA may lead to a slow heart rate after you take your first dosehere's why
GILENYA works differently from other MS treatments. One differenceyour heart rate is expected to slow down the first time you take GILENYA.
This slowdown is usually temporary. Not only that, in clinical trials, less than 1% of people taking GILENYA experienced symptoms of slow heart rate. Whether you're part of this 1% or not, you will still be monitored during your first doseso it's important for you to understand what's happening.
Why does GILENYA affect your heart?
By now, you know that MS happens when your lymphocytes, and other immune cells, mistakenly attack your central nervous system.
How can GILENYA help? GILENYA is thought to help by activating certain sensors on your lymph nodes, which keeps some white blood cells in your lymph nodes. That way, these white blood cells aren't released into your bloodstream, where they can attack your central nervous system.
GILENYA also activates certain sensors on your heart (similar to the ones on your lymph nodes), which cause your heart rate to slow down. Unlike the sensors on your lymph nodes, the effect on the sensors on your heart is temporary and only happens when you start GILENYA. This slowdown in heart rate is expected, and it's the reason you're monitored during your first dose.
If you're one of the few people who experiences symptoms of slow heart rate (such as dizziness, tiredness, or feeling like your heart is beating slowly or skipping beats), the health care professional monitoring you can help you manage these symptoms.
Symptoms of slow heart rate usually happen within the first 6 hours of your first dose, and can happen up to 24 hours after your first dose. To help you start off safely and confidently, we'll make sure your heart rate is monitored by a health care professional for these first 6 hours when you take your first dose. If your ECG shows any heart problems or if your heart rate is still too low or continues to decrease, you will continue to be observed.