The ERT process: Preparation, treatment, and aftercare
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There are many things to consider when preparing for enzyme replacement therapy (ERT), which is a treatment strategy for Pompe disease that addresses the condition’s underlying cause.
It is important to understand that ERT is not a cure for Pompe, and that patients will likely require treatment for the rest of their lives. Therefore, it is necessary to consider how ERT may affect daily life, including finances, as well as how different facets of daily life may supplement ERT, such as following optimal exercise and diet regimens.
What is enzyme replacement therapy?
ERT is a first-line treatment that aims to replace the acid-alpha glucosidase (GAA) enzyme that’s faulty or deficient for adults and children with Pompe disease.
Pompe is a rare genetic disorder caused by mutations in the GAA gene responsible for producing the GAA enzyme that normally works to break down a large sugar molecule called glycogen inside cells. As a result of these mutations, GAA is faulty or deficient, leading to toxic buildup of glycogen in the body’s tissues, especially muscles. This drives the symptoms of Pompe, which include progressive muscle weakness and wasting, breathing problems, and heart muscle damage.
ERT involves infusing a lab-made version of GAA directly into the bloodstream, working to restore the body’s supply of functional GAA. In turn, excess glycogen is broken down, easing Pompe symptoms.
There are two types of ERT currently approved to treat Pompe in the U.S. — Lumizyme (alglucosidase alfa) and Nexviazyme (avalglucosidase alfa) — both marketed by Sanofi.
Lumizyme is approved to treat people of all ages with any type of Pompe disease, while Nexviazyme is approved to treat patients ages 1 and older with late-onset Pompe.
Although outcomes vary depending on factors such as the type and severity of the disease, ERT has been shown to extend life expectancy for Pompe patients.
Another approved therapy for Pompe disease is Pombiliti + Opfolda, a combination approach of cipaglucosidase alfa, a form of the GAA enzyme, with Opfolda, an enzyme stabilizer. It is approved in the U.S. for the treatment of certain adults with late-onset Pompe disease. It is also approved in the EU and U.K.
Prepare yourself for long-term therapy
ERT infusions are administered once every two weeks by a trained healthcare provider. A standard infusion will be administered over four to seven hours, but this may change depending on the dose and infusion rate selected by the doctor.
This does not include additional time it will take to prepare the infusion and assess a person’s vital signs prior to starting treatment.
ERT is not a cure for Pompe disease, but rather a maintenance therapy to prevent glycogen accumulation. As such, patients usually will require these ERT infusions for the rest of their lives.
To avoid missing these important treatments, patients should consider how ERT sessions will fit into their daily routine, and how and when to get to the healthcare clinic for infusions.
Pombiliti, the version of the GAA enzyme that is a component of the approved combination treatment, also is administered via intravenous (into-the-vein) infusions once every two weeks. Infusions take about four hours. Opfolda, the enzyme stabilizer, is given in oral capsules to be taken an hour, and no more than three hours, before each Pombiliti infusion.
Think about your finances
Like many other treatments for rare diseases, ERT can be very expensive, especially since lifelong treatment is required.
Most insurance companies will cover the majority of the expenses, providing it is prescribed for an indication and age approved by the U.S. Food and Drug Administration.
Sanofi also offers co-pay assistance and charitable access programs to help patients cover their out-of-pocket ERT-related costs if they are uninsured or have inadequate insurance coverage.
The company’s CareConnect program can help patients learn more about their options for financial assistance.
Amicus Therapeutics, the developer of Pombiliti + Opfolda, also has an assistance program, called Amicus Assist. It is intended to help people in the U.S. navigate insurance coverage and the prescription process, and also help with financial solutions.
Supplement ERT with proper diet
ERT may be most effective when supplemented with a healthy diet. A high-protein, low-carbohydrate diet is usually recommended for Pompe patients to improve metabolism and promote muscle repair.
An optimal high-protein diet for Pompe patients consists of about 25%-30% protein, 30%-35% carbohydrates, and 40%-45% fats.
Examples of good sources of protein include:
- lean meat
- fish
- eggs
- dairy
- poultry
Several of these foods also are high in alanine, an amino acid (the building blocks of proteins) that helps slow protein breakdown and muscle damage.
Exercise
Combining exercise with ERT can help boost metabolism, promote muscle strength, and ease fatigue for Pompe patients.
Examples of exercises that could complement ERT therapy include:
- Aerobic exercises like walking, swimming, or biking, performed in moderation
- Pilates or flexibility training
- resistance training
It is important for patients not to overexert, which can exacerbate muscle damage and increase fatigue.
The optimal exercise routine may differ significantly from person to person. Patients should always speak with their healthcare team when putting together a fitness plan.
Monitor yourself for immune reactions
In some cases, the body may recognize ERT as a foreign substance and launch an immune attack against it. This can reduce the treatment’s effectiveness and lead to side effects.
In rare cases, patients may have a life-threatening allergic reaction to ERT called anaphylaxis.
Patients should monitor themselves constantly and consult a doctor if they experience symptoms of an allergic reaction, including fever, hives, rash, or difficulty breathing.
Know your ‘CRIM status’
Knowing your cross-reactive immunologic material (CRIM) status — how much GAA enzyme activity you have — is important to predict the possible outcomes of ERT. This can be determined with an enzyme activity test in the clinic.
Administering ERT to a patient who is CRIM-negative, or has no GAA activity, is more likely to cause an immune reaction and lead to a poor response to therapy than for a person who is CRIM-positive.
While patients with late-onset Pompe are virtually all CRIM-positive, those with infantile-onset Pompe disease can be CRIM-negative. These patients may require pretreatment with immune-modulating medications to prevent unwanted immune reactions against the therapy.
Pompe Disease News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
FAQs about ERT for Pompe disease
Enzyme replacement therapy is not a cure for Pompe disease, but it can slow the disease’s progression.
Both enzyme replacement therapies approved in the U.S. can be used in children. Lumizyme (alglucosidase alfa) is approved for Pompe patients of all ages, whereas Nexviazyme (avalglucosidase alfa) is approved for late-onset Pompe patients, ages 1 and older. An early start to treatment is generally thought to lead to better outcomes for patients.
Pompe disease is caused by genetic mutations that lead to a missing or dysfunctional acid-alpha glucosidase (GAA) enzyme, resulting in the buildup of a sugar molecule called glycogen that disrupts tissue function.
Delivered into the bloodstream, enzyme replacement therapy aims to supply a healthy version of GAA, restoring the body’s ability to break down glycogen, thereby easing Pompe symptoms.
Some patients may have allergic reactions to enzyme replacement therapy, which are rarely life-threatening. Side effects such as nausea, fever, itching, rash, or coughing may occur shortly after the treatment is infused into the bloodstream.
Other side effects reported in clinical trials include headache, fatigue, vomiting, dizziness, muscle pain, hives, shortness of breath, or increased blood pressure.
Enzyme replacement therapy is administered as an into-the-vein infusion once every two weeks. Each infusion may take four to seven hours, but this will depend on factors including dose, infusion rate, and a person’s tolerance to treatment.
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