Clinically meaningful neurologic worsening at Week 48 occurred in 25% of patients on standard of care versus 9% on ALXN1840 (p=0.038), while clinically meaningful improvement was seen in 45% of ALXN1840-treated patients versus 32% on standard of care. Investigator global measures favored ALXN1840 as well, with CGI-S improvement from baseline in 61% versus 17% (p=0.008) and CGI-I improvement at Week 48 in 47% versus 19% (p=0.003). Across Phase 2/3 exposure in 266 patients (median 2.58 years; max >8 years), drug-related serious adverse events were reported in 4.9% of patients, neurologic SAEs in less than 1%, and no treatment-related deaths.
The company reported these new analyses from the randomized, controlled Phase 3 FoCus trial in Wilson disease patients with neurologic symptoms at baseline, presented at AAN 2026, with durability of neurologic benefit increasing over long-term follow-up to approximately three years. Benefit was reported across treatment-naïve and treatment-experienced subgroups. The sponsor also reiterated that the pivotal program met its primary endpoint of greater copper mobilization versus standard regimens over 48 weeks and indicated plans to submit an NDA in mid-2026.
Strategically, the update reframes the asset from a copper-handling story to a clinically meaningful neurologic story, directly addressing a pain point with existing chelation and zinc-based approaches: early neurologic destabilization and inconsistent functional gains. By pairing a surrogate copper metric with multiple clinician-reported neurologic outcomes, the sponsor is assembling a dual-pronged efficacy package more likely to resonate with regulators and payers in a rare disease where functional readouts have historically been variable and small-sample. The durability narrative is notable; sustained improvement over years—if corroborated in the NDA with extension data and standardized assessments—supports positioning beyond rescue use into first-line consideration for neurologic presentations.
For research sites, the signal elevates the importance of consistent neurologic assessments in Wilson disease protocols. Expect increased emphasis on rater training, central review, and data quality around CGI and potentially complementary scales, along with longer follow-up windows to capture durability. For CROs and vendors, this tilts study design toward composite outcome frameworks that integrate biochemical control with clinician- and patient-centered measures, and may expand the role of centralized imaging or digital tools to quantify neurologic function. Sponsors competing in this space will face pressure to demonstrate not just copper normalization but reduced rates of neurologic worsening, which could reset comparator expectations and sample size calculations. Regulators gain a cleaner line of sight from surrogate to function, narrowing an approval gap that has slowed momentum in rare metabolic neurology. Patients and treating neurologists, especially those managing movement and cognitive manifestations, may see a path to earlier intervention that avoids deterioration associated with initiation of some standard therapies.
The next inflection will be the NDA package: how the sponsor handles multiplicity across neurologic endpoints, missing data in the neurologic subgroup (TMC n=77; SoC n=35), and consistency across hepatic and extra-neurologic domains. FDA’s stance on the surrogate-primary plus neurologic secondary constellation will be pivotal, as will any pediatric bridging, drug–drug interaction guidance with legacy chelators, and monitoring plans to mitigate over-depletion risks such as anemia and neutropenia. Watch for details on CMC readiness and supply for a rare disease market that relies on specialty distribution, along with whether the company pursues expedited pathways. If regulators accept the linkage between copper control and sustained neurologic benefit, the bar for future Wilson disease trials is likely to shift toward integrated clinical-biochemical endpoints and longer-term functional durability.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
