An enzyme-replacement injection for ADA-SCID
Pegademase
An enzyme-replacement injection used to treat ADA-SCID, a rare inherited condition in which the immune system does not develop properly.
What is Pegademase?
Pegademase is a specialist enzyme-replacement medicine used to treat ADA deficiency, a rare inherited cause of severe combined immunodeficiency (ADA-SCID), in which a missing enzyme leaves the immune system unable to fight infection. It works by replacing that enzyme so the immune system can recover. It is given as an injection into the muscle under specialist care. It is often used to keep children well and rebuild immunity while a longer-term treatment, such as a stem-cell transplant, is being arranged. Allergic-type reactions can occur, so it is given under close supervision.
Education and reference only. This is a plain-language guide to Pegademase — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Pegademase is an enzyme-replacement therapy for ADA deficiency, a rare inherited condition in which a lack of the enzyme adenosine deaminase (ADA) causes a build-up of toxic substances that destroy the cells of the immune system. This leads to severe combined immunodeficiency (ADA-SCID), where children cannot fight off infections and become very ill early in life. Pegademase supplies a manufactured form of the missing enzyme, given as a regular injection into the muscle. It is used under specialist care, often as a treatment to protect and rebuild immunity while definitive treatment is planned.
How it works
In ADA deficiency, the missing enzyme means toxic by-products build up and poison the developing immune cells, so the body cannot make a working immune system. Pegademase replaces the enzyme in the bloodstream, helping clear those toxic substances so immune cells can survive and the immune system can begin to recover. Because the enzyme only works while it is present, it is given as regular injections to keep its effect going. It is often used to stabilise and reconstitute the immune system while a longer-term solution, such as a stem-cell transplant, is being arranged.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist enzyme-replacement medicine used to treat ADA-SCID, a rare inherited condition that severely weakens the immune system.
Practical use
How to take Pegademase
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Have it as an injection into the muscle on the regular schedule your specialist team sets.
- Attend regular blood tests so the team can check enzyme activity and how the immune system is recovering.
- Keep taking infection precautions advised by your team, as immune protection builds gradually.
- Report any allergic-type or injection reactions, such as rash, swelling or feeling faint.
- Do not stop treatment without specialist advice, as immune protection depends on keeping it going.
Weighing it up
Advantages & disadvantages of Pegademase
Advantages
- Replaces the missing enzyme in ADA-SCID, helping the immune system recover and fight infection.
- Can protect children and rebuild immunity while a longer-term treatment is arranged.
- Offers a treatment option for a condition that is otherwise life-threatening very early.
Disadvantages
- Needs regular injections into the muscle, with the schedule guided by blood tests.
- Can cause allergic-type and injection reactions.
- Immune protection builds gradually and may not be complete, so infection precautions remain important.
Practical use
Good to know
An important point is that pegademase is often a bridging treatment: it helps protect children and rebuild their immunity while a more definitive treatment, such as a stem-cell transplant, is being planned. It is given as a regular injection into the muscle, and the schedule is set and adjusted by the specialist team based on blood tests of enzyme activity and immune recovery. Allergic-type and injection reactions can happen, so it is given under close supervision. Because immune protection builds gradually and may not be complete, careful infection precautions remain important during treatment. It should not be stopped without specialist advice, as immune protection depends on continuing it, and the team monitors immune cell counts and enzyme levels regularly.
Who should not take it / use with caution
- People who have had a serious allergic reaction to pegademase should not use it.
- It is used with care, with regular blood counts, because low blood-cell counts (including low platelets) can develop during treatment.
- It should only be used under specialist immunology supervision.
Monitoring
- Regular blood tests of enzyme activity and immune cell counts to guide the schedule.
- Watching for allergic-type and injection reactions.
- Reviewing how well immunity is recovering and planning longer-term treatment.
Side effects
- Reactions where the injection is given, such as redness, pain or swelling.
- Allergic-type reactions in some people, which should be reported.
- Rarely, blood problems such as changes in blood cell counts, which monitoring is designed to catch.
Key interactions
- It can affect blood tests that measure enzyme activity, so labs should know you are taking it.
- Certain medicines that affect the immune system, such as some used in transplant, are managed carefully by the team.
- There are few well-established routine interactions, but tell your team about everything you take.
Available as: A solution for injection into the muscle.
Answers
Pegademase: frequently asked questions
What is pegademase used for?
It is used to treat ADA deficiency (ADA-SCID), a rare inherited condition that leaves the immune system unable to fight infection, by replacing the missing enzyme so immunity can recover.
Is it a permanent cure?
It is often used to protect and rebuild immunity while a longer-term treatment, such as a stem-cell transplant, is being arranged, rather than as a permanent cure in itself.
How is it given?
It is given as a regular injection into the muscle, with the schedule set and adjusted by the specialist team based on blood tests.
Do I still need to avoid infections?
Yes. Immune protection builds gradually and may not be complete, so the infection precautions your team advises remain important during treatment.
Can it be stopped once I feel well?
No. Immune protection depends on continuing it, so only change or stop treatment on specialist advice.
Authoritative sources
- BNF
- NICE CKS
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