Newer Enzyme Therapies Were Feasible After Alglucosidase Alfa in Pediatric-Onset Pompe Disease
A small Korean single-center cohort suggests that switching from alglucosidase alfa to newer enzyme replacement therapies can be done safely in selected patients with pediatric-onset Pompe disease. The experience is limited, but it offers a practical view of how clinicians are already adjusting treatment when standard therapy no longer feels sufficient.
Six patients with Pompe disease were included, four with infantile-onset disease and two with late-onset disease. Four switched to avalglucosidase alfa and two to cipaglucosidase alfa plus miglustat. Across the available follow-up, no severe post-switch infusion-related reactions or anaphylaxis occurred. For a disorder in which lifelong infusion therapy is often started early and continued for years, tolerability is not a minor detail; it determines whether a switch remains possible at all.
Why Clinicians Consider a Switch
Pompe disease is a lysosomal storage disorder caused by acid α-glucosidase deficiency. In clinical practice, enzyme replacement therapy has changed survival and disease trajectory, yet long-term limitations remain. Some patients continue to show incomplete clinical response, others struggle with suspected treatment-related intolerance, and some face access issues that force treatment changes. Those realities drove the switch decisions in this cohort.
The study focused on six patients treated at Samsung Medical Center between 2021 and 2024, with follow-up through October 2025. The median age was reported as 17.5 years, with a range from 2.08 to 23.0 years. Post-switch follow-up ranged from 1.67 to 4.17 years. That span is not long enough to settle the question of durable disease modification, but it is long enough to examine early safety and whether a therapy change produces obvious harm.
Switching was not driven by a single uniform reason. Some patients changed therapy because of suboptimal clinical response, some because of suspected intolerance, some because of drug access problems, and others as part of treatment optimization. In a rare disease clinic, those motivations often overlap. A family may be seeking a better biochemical profile while the care team is also trying to preserve respiratory function, motor performance, or infusion tolerability.
Safety After the Switch Stayed Acceptable
The clearest message from this cohort is simple: the newer therapies were tolerated. No severe infusion reactions or anaphylaxis were documented after the transition. For patients with Pompe disease, this matters because infusion complications can interrupt treatment and complicate future therapeutic planning. A switch that looks attractive on paper becomes useless if the new agent provokes immediate intolerance.
The small sample size limits any claim of broad safety, but the experience still provides reassurance for clinicians who worry about cross-reactivity or clinical destabilization when changing from one enzyme product to another. The practical result is a short list of patients who were able to continue disease-directed treatment without dramatic acute toxicity.
Biochemical and Functional Changes Were Mixed but Directionally Encouraging
Outcomes after the switch were not identical across the cohort. During follow-up, selected patients showed improvement in biochemical, functional, or respiratory measures, while others remained clinically stable. No single endpoint captured the entire experience, and the pattern was not uniform enough to support a claim of superiority for either newer product.
Even so, stability itself has value in Pompe disease, especially in patients who were changed because of an inadequate response to prior therapy. For chronic neuromuscular disease, slowing decline can be clinically meaningful even when dramatic improvement does not occur. Respiratory preservation, maintenance of function, and biochemical improvement all carry bedside weight, particularly in pediatric-onset disease where long horizons magnify small differences over time.
The data also suggest that a switch can be used as a strategy rather than a rescue maneuver alone. In some patients, treatment optimization appeared to be the main goal. In others, clinicians were trying to avoid the possibility that ongoing therapy with the original agent was failing quietly. That kind of judgment is common in inherited metabolic disease, where progression may be gradual and biomarkers do not always mirror day-to-day function.
What This Korean Experience Can and Cannot Tell Us
This was a retrospective single-center study, and the sample was extremely small. Six patients cannot define a standard of care, and the cohort was not designed to compare avalglucosidase alfa with cipaglucosidase alfa plus miglustat head to head. The report is descriptive, not definitive. It does, however, show how pediatric-onset Pompe disease is being managed in real life when first-line enzyme therapy is no longer enough.
The study also reinforces a broader problem in rare disease therapeutics: long-term evidence often lags behind clinical need. Physicians and families make treatment decisions before large prospective datasets are available. In that setting, real-world observations become important, especially when they include both safety and early outcome signals.
A longer follow-up period will be needed to determine whether the biochemical and functional gains seen in some patients persist, whether respiratory measures continue to improve, and whether treatment access or tolerability issues recur after the switch. The current dataset cannot answer those questions. It can only show that switching was feasible in this small cohort, and that the transition did not trigger severe acute safety problems.
For clinicians caring for patients with pediatric-onset Pompe disease, that is a meaningful but limited message. The decision to change enzyme therapy still depends on individualized assessment of response, tolerance, and access, and the next step is larger prospective study rather than extrapolation from six cases.