Merz Therapeutics has submitted a marketing authorization extension to the European Medicines Agency (EMA) for XEOMIN (incobotulinumtoxinA), seeking approval to treat both lower and upper limb spasticity in children and adolescents aged 2–17 years. The submission is backed by positive data from the Phase 3 ELLIE trial and earlier pediatric studies, potentially expanding therapeutic options for children with cerebral palsy and other neurologically driven spasticity disorders across the European Union and European Economic Area.

Why this application could redefine real-world treatment standards for pediatric limb spasticity

Spasticity in pediatric patients—especially those with cerebral palsy—remains an undertreated condition despite its impact on mobility, independence, and quality of life. Nearly 80 percent of cerebral palsy cases are characterized by spastic forms, often involving both lower and upper limbs. These impairments affect not only ambulation but also fine motor skills, feeding, and communication in severe cases. Current neurotoxin treatments are approved for select limb targets or restricted by age group, creating a fragmented treatment landscape across Europe.

What makes Merz Therapeutics’ filing notable is not simply the inclusion of XEOMIN for lower limb spasticity in children, but the simultaneous inclusion of upper limb treatment in the same regulatory submission. This reflects a more holistic approach to managing pediatric spasticity, which often requires multipattern interventions across several muscle groups. Clinicians treating moderate to severe cerebral palsy routinely address both upper and lower limbs in the same therapeutic cycle, yet few products are approved to support that workflow with regulatory confidence.

The ELLIE trial, a 28-week, two-stage, double-blind, multicenter Phase 3 study, directly addresses this clinical gap. In addition to validating efficacy for lower limb spasticity using incobotulinumtoxinA, it provided a framework for flexible dosing that could accommodate upper limb involvement where necessary. Industry observers point out that this design better mirrors day-to-day clinical practice, making the results more relevant to pediatric neurologists, physiatrists, and rehabilitation specialists.

If the EMA approves the indication, XEOMIN would become one of the few botulinum neurotoxins in Europe with formal approval for treating both limb types in children—a distinction that may offer competitive positioning in hospital formularies and national tender systems.

How ELLIE trial design strengthens Merz’s regulatory and clinical case

ELLIE’s significance lies not just in its results, but in how it was designed and executed. Unlike earlier pediatric neurotoxin studies that focused on single-limb treatment or observational endpoints, ELLIE adopted a placebo-controlled, prospective format across multiple European centers. This not only supports statistical rigor but allows for a diverse patient population reflective of pan-European treatment environments.

The trial evaluated changes in spasticity using standardized scales like the Modified Ashworth Scale and Global Clinical Impression scores, aligning with EMA and clinical community expectations for meaningful outcome measures. The 28-week duration allowed researchers to observe both short-term efficacy and durability of effect, while also monitoring safety signals across repeat dosing intervals.

Clinicians familiar with the data presented at the TOXINS 2026 Congress suggest the safety profile for incobotulinumtoxinA remained stable, with no new tolerability concerns and a low incidence of treatment-related adverse events. This is critical in pediatric populations, where concerns around immunogenicity, systemic toxicity, and long-term muscle atrophy often shape both regulatory decisions and parental consent in real-world settings.

The regulatory dossier submitted to the EMA includes the full ELLIE dataset alongside findings from earlier Merz-sponsored pediatric studies, giving regulators a cumulative safety and efficacy picture that spans multiple trials and treatment regimens. That breadth may be key in supporting a pan-limb approval rather than a restricted lower limb-only label.

What this filing reveals about Merz Therapeutics’ long-range strategy in specialty neurology

Merz Therapeutics has spent the last decade repositioning itself as a neurology-first specialty pharmaceutical company, and this pediatric XEOMIN filing underscores its ambition to extend that strategy into underserved age groups and indications. The company has historically focused on adult movement disorders, such as cervical dystonia and post-stroke spasticity, but is now signaling a willingness to engage with more complex clinical and regulatory spaces.

Pediatric drug development in Europe is notoriously difficult, particularly for neurotoxins. The additional requirements for Pediatric Investigation Plans (PIPs), stricter scrutiny on safety, and the need to demonstrate caregiver-relevant endpoints often dissuade larger players from pursuing such filings. That Merz Therapeutics chose to advance a full pediatric application—with both limb regions included—suggests a confident bet on clinical differentiation and payer receptivity.

Industry strategists suggest the move is also designed to future-proof Merz’s position in the face of growing innovation from rivals. Competitors such as Ipsen (with DYSPORT) and Revance Therapeutics (with RHA-based neurotoxin platforms) are expanding into new formulations and indications. At the same time, next-generation neurotoxins with longer duration of effect or improved reconstitution protocols are being developed to target both adult and pediatric segments.

By advancing XEOMIN into pediatric indications, Merz Therapeutics is effectively building brand loyalty earlier in the treatment lifecycle. Hospitals and neurology clinics that adopt XEOMIN for pediatric use may be more likely to continue prescribing it for adolescent and adult transitions, thereby locking in future volumes. Moreover, approval in Europe could provide a platform for follow-on filings in Canada, Brazil, and Asia-Pacific markets, which often reference EMA outcomes during local regulatory reviews.

What reimbursement and adoption hurdles could limit XEOMIN’s pediatric potential

Despite its clinical strength and regulatory clarity, XEOMIN’s commercial success in pediatric spasticity will depend heavily on market access dynamics. Reimbursement policies for pediatric neurotoxins vary widely across the EU, with some countries bundling such therapies into rehabilitation packages and others requiring indication-specific approval by national health bodies.

Pediatric dosing is also a complicating factor. Unlike adults, where weight-based dosing is less critical, children require tightly controlled dosage titration to balance efficacy with safety. This increases the burden on clinicians and pharmacists, especially in hospitals with limited neurotoxin experience. Merz will likely need to invest in extensive education, training, and pharmacovigilance infrastructure to support widespread adoption.

Further, while XEOMIN’s lack of complexing proteins may reduce the risk of neutralizing antibody formation—a theoretical advantage in long-term pediatric use—there is limited real-world evidence comparing immunogenicity across neurotoxins in children. Payers and health technology assessment agencies may demand longer-term post-marketing data to justify switching from entrenched brands like BOTOX.

Clinicians may also hesitate to switch without clear comparative effectiveness data. Although XEOMIN has demonstrated non-inferiority to BOTOX in prior adult studies, pediatric head-to-head data are scarce. In the absence of direct comparative trials, uptake may hinge on pricing strategy, availability in national tenders, and logistical factors like reconstitution time and shelf stability.

Where future developments could shift the competitive and regulatory landscape

The pediatric neurotoxin space is no longer a regulatory backwater. With increasing demand for early motor intervention in conditions like cerebral palsy, genetic disorders, and post-traumatic neurodevelopmental conditions, companies are recalibrating their R&D pipelines to capture this unmet need. Merz Therapeutics’ EMA filing could trigger a new wave of pediatric-focused neurotoxin trials, especially if the product receives favorable label language or broad age-range approval.

Regulators, too, are evolving. The EMA has expressed greater willingness to consider extrapolation from adult data when supported by robust pediatric safety findings, particularly for chronic, quality-of-life impairing conditions. The fact that XEOMIN is already approved in adult spasticity across Europe and the U.S. may allow for smoother integration of this pediatric indication into broader treatment guidelines.

From a broader policy perspective, expanding pediatric indications for neurotoxins could also feed into public health frameworks promoting early intervention and mobility independence. As more countries adopt value-based care models, treatments that reduce future orthopedic complications or caregiver burden may be prioritized for reimbursement.

For Merz Therapeutics, the success or failure of this application will serve as a bellwether for its overall pediatric ambitions. If approved, it will not only validate the company’s R&D investments but could cement XEOMIN’s place in the evolving hierarchy of neurotoxin-based therapies.

  botulinum neurotoxin, cerebral palsy, ELLIE trial, European Medicines Agency, incobotulinumtoxinA, Merz Therapeutics, pediatric spasticity, Phase 3 trial, XEOMIN