9 Investigator Site Networks Operating in Europe in 2026

A clinical investigator site network is where a trial actually happens: the physical location, staff, and principal investigator responsible for enrolling and treating patients according to protocol. Across continental Europe, that work spans purpose-built Phase 1 pharmacology units run independently or spun out of universities, general-practice networks that embed trials into primary care, and multi-country research site platforms built through acquisition.

The investigator site networks below are listed in no particular order and span eight European countries. Between them, these companies and providers cover Phase 1 healthy-volunteer units, general-practice investigative site networks, multi-country oncology-focused platforms, and therapeutic-area specialist CROs with their own clinical facilities.

Altis Medical Research Organization

Altis Medical Research Organization was founded in 2001 by Dr. E. Mehmet Yusuf, who previously spent roughly a decade as a Medical Coordinator at Hoffmann-La Roche before starting the company as one of Turkey's pioneering CROs. Approved by the Turkish Ministry of Health's General Directorate of Pharmaceuticals and Pharmacy, Altis now operates with more than 130 staff across 17 cities in Turkey, running Phase 1-4 clinical trials, observational studies, and clinical research training programs. The company's clinical trial training services, delivered primarily for Roche, are among its most sought-after offerings alongside its core trial execution work. Altis also founded AlfaBeta CRO, described as the first biostatistics firm in Turkey, as a sister company supporting its clinical operations.

Centre for Human Drug Research (CHDR)

The Centre for Human Drug Research (CHDR) operates an independent, non-profit early-phase CRO in Leiden, founded in 1987 by pharmacologist Douwe Breimer, who identified the need for a dedicated clinical research unit connected to a top-tier medical and pharmaceutical sciences university. CHDR's purpose-built Phase 1 unit holds 54 beds, supplemented by an 8-bed hospital-based unit at Leiden University Medical Center for higher-risk compounds and a 12-bed unit at Medisch Spectrum Twente for neurology and pain studies. The company has developed proprietary research tools including NeuroCart and PainCart, used to generate pharmacodynamic biomarker data in early-phase trials across therapeutic areas such as neurology, immunology, and dermatology. CHDR conducts roughly 40 industry-sponsored early-phase trials annually and has published more than 250 scientific articles over its history while training more than 2,000 students in clinical pharmacology.

Convex CRO

Convex was established in 1991 as an independent Bulgarian research company, founded by a clinical researcher who has said 30 years in the business exposed the strengths and weaknesses of investigational sites before he built the country's first fully independent clinical research center meeting EU standards. The company operates an incorporated Clinical Research Centre with a Phase I Pharmacological Unit in Sofia, and separately manages its own network of investigator sites, including university and public hospitals and private medical centers, for multi-center trials across Bulgaria. Convex has completed more than 700 clinical studies over 35 years spanning Phase I–IV drug trials, bioequivalence and bioavailability studies, and trials on medical devices and food supplements. The company presented its capabilities at the 2026 SCOPE Summit in Orlando, highlighting its Sofia early-phase unit to biotech and pharma sponsors.

DELPHINIUM

DELPHINIUM operates a 12-bed Phase I clinical research unit in Groningen, the Netherlands, built specifically to serve smaller biotech companies that lack their own clinical trial facilities. The company is led by CEO Jitske Beukema, who brings more than 30 years of experience in Phase I healthy volunteer and patient studies, alongside COO and CMO Dr. Christine Voors-Pette, a principal investigator with more than 15 years of experience who has personally run over 50 early-phase clinical studies, most of them first-in-human trials. DELPHINIUM's location on the campus of University Medical Center Groningen gives it direct access to academic specialists and imaging resources when a study requires them, and the company reports achieving ethics approval within roughly 30 days on average. The team joined Campus Groningen's BioTech Center as a new tenant, positioning DELPHINIUM within an emerging life sciences innovation hub on the Healthy Ageing Campus.

gp4research

gp4research operates what it calls an Investigative Site Network (ISN), an international group of independent general practices that function as a single clinical trial entity, embedding research directly into primary care settings across multiple European countries. The company was founded as a spin-off of the Medical University of Gdańsk and won the 2019 EIT Health Start-ups Meet Pharma competition responding to a challenge from Bayer AG on managing motor complications in Parkinson's disease. Each GP in the network draws on a dedicated pool of roughly 2,000 patients cared for from birth through end of life, giving the network access to patients who might not otherwise reach a specialist research center. gp4research also offers centrally managed home care services for clinical trial visits through a partnership with Medsource, building on home-care expertise the company's leadership has developed since 2010.

Pratia

Pratia describes itself as the world's largest Oncology Research Organization, operating a network of more than 100 clinical research sites across eight countries and reporting more than 3,000 completed clinical trials since its 2012 founding. The company, part of the Humaneva Group and majority-owned by listed pharmaceutical wholesaler NEUCA since 2022, expanded into Slovakia and deepened its Czech Republic presence in January 2025 through the acquisition of CRC (Clinical Research Centre), a network with more than 140 investigators. Pratia joined the Association of Multisite Research Corporations (AMRC) as its fifteenth member, becoming the trade group's newest representative for European site networks. The company positions itself as capable of running about 85 percent of all therapeutic areas and protocol designs, supported by a technology platform built for hybrid and decentralized trial models.

Profil

Profil began as a spin-off of the Department of Metabolic Diseases and Nutrition at the University of Düsseldorf in 1999, and has since become what it describes as the world's leading CRO focused specifically on diabetes and obesity research. The company operates two in-house clinics, in Neuss and Mainz, with more than 80 combined beds, and draws on a recruitment database of more than 30,000 people with diabetes to support its trials. Profil's core technical expertise centers on glucose clamp studies, which the company runs using ClampArt, its own proprietary automated glucose clamp device capable of running up to 26 continuous glucose clamps in parallel. The company has contributed to the development of every major class of anti-diabetic compound currently on the market and has published more than 360 papers in peer-reviewed journals.

Quinta-Analytica

Quinta-Analytica operates two in-house clinical units at its Prague facility, spanning roughly 1,000 square meters and 64 beds, where it runs Phase I bioequivalence and bioavailability studies capable of dosing up to 60 subjects in parallel. Founded in 1997, the company pairs its clinical operations with an in-house bioanalytical laboratory using HPLC-MS/MS instrumentation to measure active substances and metabolites in biological samples collected during its trials. Quinta-Analytica has passed multiple FDA inspections across GMP, GLP, and GCP without findings, most recently in 2015, and maintains additional operations in Brno and Ostrava. In 2025, the company earned an EcoVadis Bronze Medal, joined the United Nations Global Compact, and worked with partner Swipp to help bring what the companies describe as the world's first midazolam buccal film into clinical trials.

Smart Medico

Smart Medico was established in January 2005 as a local Contract Research Organization headquartered in Zagreb, Croatia, and has since focused on organizing and managing clinical operations across Croatia, Slovenia, and Bosnia and Herzegovina for pharmaceutical and biotech sponsors as well as larger multinational CROs. The company's founding management team brought more than 10 years of prior basic research and drug development experience to the business, working on projects spanning from laboratory bench to patient bedside. Smart Medico positions the South Eastern European region it operates in as advantageous for clinical trials, citing a largely treatment-naive patient population and strong recruitment rates in the region. The company emphasizes flexibility, responsiveness, and cost-effectiveness as differentiators for sponsors evaluating Central and Eastern European trial sites.

Explore the full Investigator Site landscape

The companies above represent a portion of a much larger field.

Diligent's platform includes over 280 Investigator Site Vendors, with Vendor qualification data available on demand. Talk to our team about accessing qualification data for this category.

This article is intended as an informational overview of vendors operating in this space. Inclusion on this list does not constitute an endorsement, recommendation, or qualification by Diligent.