People with Gaucher disease, an inherited condition, don’t make enough of the properly functioning enzyme, glucocerebrosidase (GCase). Your body needs GCase to break down a fatty chemical called glucocerebroside. Without GCase, the buildup of glucocerebroside becomes toxic and leads to organ damage.
Enzyme replacement therapy (ERT), which addresses this enzyme deficiency, is the primary treatment for Gaucher disease. We spoke with Dr. Gregory Grabowski, a Gaucher expert, to get answers to common questions about ERT for Gaucher disease.
Dr. Grabowski is a professor emeritus at the University of Cincinnati College of Medicine and the Cincinnati Children’s Hospital Medical Center. He developed the first treatment center for Gaucher disease and has devoted decades to researching treatments for Gaucher and other genetic diseases. He is a member of the National Gaucher Foundation’s Medical Advisory Board.
FAQs About ERT for Gaucher Disease
What is ERT for Gaucher disease?
ERT provides a modified version of the Gcase enzyme. You receive ERT through an intravenous (IV) infusion, which typically takes about two hours. Most people with Gaucher disease receive an enzyme infusion approximately every two weeks.
With Gaucher disease, “you must regularly replenish the enzyme in your cells with ERT. And we’ve seen it works well for people with this condition,” says Dr. Grabowski.
Read more about how enzyme replacement therapy works and the different options available.
Can you skip an ERT infusion?
“It depends on where you are in your therapy,” Dr. Grabowski says. “It also depends on what stage of Gaucher disease you’re in.”
He says to determine whether you can skip an ERT infusion, your care team must consider:
- How fast the condition is progressing
- How long you’ve been on ERT
- How severe your symptoms or signs are
“Several years ago, we saw some of the effects of skipping enzyme replacement therapy doses,” Dr. Grabowski says. In 2010, there was a disruption in the production of GCase for Gaucher disease, and the enzyme was not available in some areas for many months. Some people who had been doing well on ERT for years quickly started to have Gaucher disease symptoms or signs again. But for others, it took several months of no ERT before symptoms or signs began to worsen.
Dr. Grabowski advises that for someone who has severe symptoms or signs, it’s ideal to have consistent ERT infusions for several years before considering skipping a dose. “We wouldn’t want someone like this to skip doses at first because they can regress and start having worse symptoms or signs,” he says.
Once you’ve been on ERT for many years, if your organs are healthy, and if you’re not having health problems related to Gaucher disease, you may be able to take a brief break from ERT. “Maybe you want to skip a dose so you can take a trip, for example. This is a decision you and your provider would make together,” Dr. Grabowski says. “Typically, it’s not something you want to do very often. But if your condition is mild, you may be able to skip a dose now and then without concern.”
Can you get shorter ERT infusions?
Standard ERT infusions take about two hours. According to Dr. Grabowski, shorter infusions may work, too.
“However, shorter infusion times have not been well-studied,” he cautions. “An infusion as short as 30 minutes may be fine, but I don’t recommend going shorter than that because we don’t know if shorter infusions are still effective. Most patients are still getting their infusions over an hour and a half to two hours, and that’s the current prescribed infusion time. A shorter infusion time would need to be tested in each person.”
Why do you need to refrigerate ERT powder?
“The need for refrigeration has to do with the stability of the enzyme,” Dr. Grabowski says. “To make sure the enzyme powder doesn’t deteriorate, keep it in the refrigerator according to the instructions.”
He adds that the enzyme degrades much more quickly once mixed with saline solution for an infusion. “The enzyme is an extraordinarily expensive substance, so we don’t want to waste it or give you an infusion that’s less potent,” he says. “This is why the pharmacist at the treatment center usually will wait until you arrive before mixing up the enzyme solution for your IV.” If you do home infusions, following enzyme storage and preparation instructions is essential, too.
How fast does the enzyme leave your body?
“The enzyme typically leaves the bloodstream and absorbs into tissues in about 15 to 20 minutes,” Dr. Grabowski says. At that point, the enzyme is no longer present in your blood, but it is still in your body.
He says about half of the enzyme may stay active in your cells for about four days. During that time, your cells use and then break down the enzyme. After about one week, the infused enzyme is likely no longer present in your body at all. “This is where we gained the understanding that people would probably need infusions every two weeks,” Dr. Grabowski says.
But he adds that only some people need their infusions spaced exactly two weeks apart. Some people require weekly infusions, while other people may need an infusion only every three weeks. “Infusion timing is very individual and has to be worked out between you and your provider,” he says.
Why do some people get itchy after ERT infusions?
“After getting many infusions year after year, some people develop irritation at the sites of the infusion. This itchiness may be from skin or vein irritation,” Dr. Grabowski says. “This irritation is the most common explanation for itching.”
Reactions can also happen if you have a latex allergy and the person giving your infusion wears latex gloves. You may also have a mild skin reaction to the adhesive tape used to secure the IV.
“Some people develop an allergy to the ERT itself, but this is very rare. If this happens, we can adjust the enzyme, and most people can continue treatment without problems,” assures Dr. Grabowski.
How long do you have to stay on ERT for Gaucher disease?
Many people on ERT want to know how long they have to continue infusions. Can you ever go off ERT?
“No, most people with Gaucher disease will need to continue ERT for life,” Dr. Grabowski says. “We recognize it is a burden to drive to where you get the infusion and spend at least two hours at the center to get the ERT. So, in some cases, we can shorten the infusion time or space out the infusions a little more to make them more convenient.”
Some people live hours away from an infusion center, making accessing regular infusions difficult. Home infusions may be a helpful option if access or transportation to appointments is a challenge.
Future Gaucher Disease Treatments
According to Dr. Grabowski, the next possible Gaucher disease treatment likely will be gene therapy. He reports many companies and researchers are working in this area. “They’re looking at several different kinds of gene therapies, including modifying someone’s own bone marrow to make healthy cells that can produce the normal GCase enzyme.”
Another possible approach uses a type of virus that is present in all people, called adeno-associated viruses, which don’t cause any disease in humans. “We can potentially program this virus to deliver the gene that would cause the body to make GCase,” he says. “This is a major area of current research.”
Dr. Grabowski expects there will be many clinical trials in the next few years to test gene therapy and other treatments for Gaucher disease and other lysosomal storage diseases (LSDs). Some, including fetal therapy clinical trials for LSDs, are already underway.
How the National Gaucher Foundation Can Help
If you or a loved one lives with Gaucher disease, the National Gaucher Foundation is here for your family. We offer resources to optimize your health with Gaucher disease and connect you with the support you need.
SOURCES
- National Gaucher Foundation — Enzyme Replacement Therapy https://www.gaucherdisease.org/gaucher-diagnosis-treatment/treatment/enzyme-replacement-therapy/
