Across 61 Alzheimer’s disease and dementia phase II/III CTIS trial records from 2024–2026, European site activity is not dominated by one country alone. Spain, Czechia, Poland, Slovakia, Belgium, France, and Germany repeatedly appear as operational hubs, with the strongest recurring site signals around Barcelona, Leuven, Prague/Brno-region Czech neurology networks, and Slovak neurology/psychiatry sites.
The top 10 site ranking is based on repeated appearance across Alzheimer’s disease and dementia phase II/III geography records. The leading cluster is Barcelona/Catalonia, followed by Belgium’s Leuven network and recurring Czech and Slovak neurology or neuropsychiatry sites.
The Alzheimer’s site landscape looks more network-based than single-institution dominated. Repeated participation clusters around memory clinics, neurology departments, psychiatry/neuropsychiatry centers, and specialized Alzheimer’s research groups rather than only large academic hospitals.
Of 61 Alzheimer’s disease and dementia phase II/III CTIS geography records, 33 were phase II or phase II-containing records and 28 were phase III or phase III-containing records. This corresponds to 54.1% phase II and 45.9% phase III.
The balanced phase II/III split suggests that European Alzheimer’s infrastructure is being used both for confirmatory development and for earlier proof-of-concept, dose, biomarker, or mechanism-focused programs.
The strongest recurring country signals were Spain, Czechia, Poland, Slovakia, Belgium, France, Germany, Portugal, Hungary, and Sweden. Spain appeared as a high-density country across multiple records, including records with 5–7 sites and participant allocations of 30, 43, and 120 participants in individual country blocks.
Alzheimer’s trial execution appears to depend on a mix of large academic memory centers and distributed community-facing neurology or psychiatry networks. This is consistent with the need to identify cognitively impaired participants through both specialist dementia clinics and broader outpatient referral channels.
Selected high-allocation country blocks included Spain with 120 participants in one phase III record, Germany with 69 participants in one phase II record, Poland with 60 participants in one 2026 record, Spain with 43 participants in another phase III record, and Slovakia with 36 participants in one 2026 record.
Spain stands out not only by recurring site participation but also by high participant allocation in selected phase III records. Poland and Slovakia show the opposite operational pattern: distributed networks of smaller or ambulatory sites that can still contribute meaningful country-level enrollment capacity.
The Alzheimer’s phase II/III European site landscape is distributed rather than dominated by a single mega-center. The most commercially useful pattern is the repeated combination of Barcelona memory-clinic infrastructure, Belgian academic neurology sites, Czech neuropsychiatry networks, Slovak ambulatory neurology/psychiatry sites, and Polish distributed private-site capacity.
For Alzheimer’s studies, site selection should be interpreted as a country-network question rather than a single-site ranking exercise. The recurring sites identify experienced anchors, but enrollment scale appears to come from combining these anchors with distributed neurology, psychiatry, geriatric, and memory-clinic networks.