12 Investigator Site Networks for Clinical Trials in 2026

An investigator site or clinical investigator site network is where a clinical trial actually happens: the physical location, staff, and principal investigator responsible for enrolling and treating patients according to protocol. The organizations that run these sites take several different forms, from site management organizations that own and operate their own dedicated research centers, to integrated research organizations that embed clinical trial infrastructure inside existing physician practices and hospital systems, to specialist early-phase units built for first-in-human and Phase 1 work.

The investigator site networks below are listed in no particular order and span the US, Australia, and the UK. Between them, these companies and providers cover multi-specialty site networks, oncology-focused hospital and community practice networks, early-phase and Phase 1 specialist units, and integrated research organizations built around a specific therapeutic area.

Alliance for Multispecialty Research (AMR)

Alliance for Multispecialty Research (AMR) began in 1994 as a shared marketing and best-practices hub for independent clinical research centers before 15 member centers merged into a single company in 2017. The network now spans 32 wholly owned and affiliate research centers across the continental US, with more than 126 investigators and access to a database of over 657,000 patients built from decades of prior studies at member sites. AMR has conducted more than 7,700 clinical trials and enrolled over 145,000 participants to date, and the company is a four-time winner and 2024 finalist for the Vaccine Industry Excellence Award for Best Clinical Research Site or Network. Membership in the AMR network is determined through a peer review process evaluating a site's quality standards, operational breadth, geography, and therapeutic expertise.

American Oncology Network (AON)

American Oncology Network (AON), a Nasdaq-listed company (AONC), is a 100% physician-led alliance of community oncology practices that has grown into one of the fastest-growing oncology networks in the US since its 2017 founding. AON practices offer patients access to more than 150 active clinical trials, with four sites designated as strategic research sites for the Sarah Cannon Research Institute. The company operates a central laboratory in Fort Myers, Florida that earned reaccreditation from the College of American Pathologists in 2025 following an on-site inspection. AON physicians and executives presented 24 research studies at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting, part of a network representing more than 290 providers across 21 states.

DM Clinical Research

DM Clinical Research, founded in 2006 by CEO Mohammad Millwala, operates an integrated national network of clinical trial sites headquartered in Houston, including wholly owned research centers and physician-embedded sites across therapeutic areas spanning vaccines, internal medicine, pediatrics, gastroenterology, and psychiatry. The company won the 2023 Best Clinical Trial Network award at the Vaccine Industry Excellence Awards and the Society for Clinical Research Sites' 2022 Excellence in Patient Centricity Award. DM Clinical Research expanded to 24 dedicated research centers by 2024, opening new locations in Boston, Chicago, Detroit, Philadelphia, and Phoenix during what the company describes as a period of transformational growth, during which its staff size quadrupled. The company has run vaccine studies in partnership with sponsors including Moderna, targeting underserved communities across its multi-city footprint.

Elite Clinical Network

Elite Clinical Network (ECN) operates a closely controlled group of pharmaceutical research sites across California, Arizona, and Nevada rather than a traditional site management organization model, drawing on a proprietary database of more than 100,000 research study candidates. Established in 2003 and based in Nevada, the company reports it can screen its first study subjects on day one of site activation and typically meets or exceeds sponsor enrollment goals within six months. In September 2023, Dallas-based Surge Private Equity formed a strategic partnership with ECN in a transaction valued at roughly $200 million, with debt financing from affiliates of MGG Investment Group. Christopher Brennan was appointed CEO of the network in 2025 as it continued expanding its footprint across the western US.

Epic Medical Research

Epic Medical Research operates an independent outpatient clinical research network with clinics across Arizona, Oklahoma, and Texas, and the company says it enrolled the first patient in Pfizer's Paxlovid clinical study. The Dallas-based company reports its data collection has contributed roughly 8 percent of the total global dataset on monoclonal antibody treatments, and it actively partners with Native American, African American, Hispanic, rural, and LGBTQIA+ communities as part of a stated diversity mission, with staff fluent in 11 languages. In August 2025, Epic Medical Research joined hyperCORE International's global partner site network, a shared-ownership alliance of research site organizations spanning more than 80 active sites across five countries. The company's leadership team brings a combined 40-plus years of clinical research experience.

FOMAT Medical Research

FOMAT Medical Research is a founding member of hyperCORE International, a mutual-ownership alliance of independent clinical research site networks launched to address fragmentation across the site management industry. Based in Oxnard, California, FOMAT operates a network described as California's largest research site organization, with more than 50 investigators across 26 sites and a patient database of roughly 534,000 people, built partly through its acquisition of Diverse Research Solutions, the company it originally spun off from. FOMAT was named Innovative Business of the Year by the Oxnard Chamber of Commerce in 2020 and was a finalist for the Society for Clinical Research Sites' Site Patient Recruitment Innovation Award in 2022. In 2026, FOMAT acquired Topography Health, a move the company says made it the largest embedded research organization in the US.

Hammersmith Medicines Research

Hammersmith Medicines Research (HMR) has specialized in early-phase clinical trials since 1993 and grew into what it describes as the largest CRO of its kind in the UK, running a 145-bed, purpose-built London facility with a resident 24/7 resuscitation team, on-site pharmacy, radiopharmacy, and laboratory. The company holds MHRA Phase 1 accreditation for first-in-human trials, along with licenses covering controlled drug substances and radiolabelled study drugs, and has won three Queen's Awards for Enterprise or Exports. HMR was acquired by Nucleus Network in 2025, a deal that gave the combined organization dedicated early-phase facilities across Australia, the US, and the UK for the first time. The roughly 270-person HMR team continues to operate its London site as part of Nucleus Network's global early-phase network.

Nucleus Network

Nucleus Network describes itself as the only Phase 1 clinical research organization with dedicated facilities in both Australia and the US, running more than 200 beds across sites in Melbourne, Brisbane, and Minneapolis that are co-located within major hospital and biotech precincts. Founded in 2004, the company has conducted more than 1,500 early-phase trials, with roughly 80 percent of its clients based in US biotech and pharmaceutical companies, and offers specialized capabilities including onsite dialysis for renal studies and infrastructure built for high-volume biosimilar trials. Blackstone announced an agreement to acquire Nucleus Network in 2024, describing it as Australia's largest Phase 1 clinical trials specialist. The company's 2025 acquisition of Hammersmith Medicines Research added a fourth site in London, extending its early-phase network to three countries.

Paratus Clinical

Paratus Clinical was established in 2015 to operate outside Australia's public health system, letting the company respond to sponsor timelines more quickly than institutionally embedded research sites. The company now runs six wholly owned clinical sites along Australia's East Coast, delivering Phase I–IV research and reporting more than 200 awarded clinical trials from pharmaceutical, biotech, and CRO sponsors as of 2026, up from roughly 80 trials in 2024. Paratus was a founding member of the Pacific Clinical Research Network ANZ, a group that has grown to 17 dedicated research sites across Australia and New Zealand. CEO Megan Morrison leads the company, which reported approximately $5.1 million in annual revenue in 2025.

Sarah Cannon

Sarah Cannon, the oncology service line of HCA Healthcare, unites more than 250 affiliated cancer care sites across 20 US states and the UK, and its research arm is responsible for more than 4,500 clinical trial enrollments each year, including over 750 first-in-human studies. The organization formed the Sarah Cannon Research Institute (SCRI) in 2004 and became HCA Healthcare's dedicated Cancer Institute in 2012, growing into what it describes as one of the largest patient-centric clinical trial organizations in the world. In 2022, SCRI formed a joint venture with McKesson's former US Oncology Research division, combining the two networks' physicians into a group actively enrolling patients at more than 250 locations across 24 states. Sarah Cannon is also the largest provider of cellular therapy in the US, performing more than 1,600 transplants and cellular therapies annually.

Summit Clinical Research

Summit Clinical Research was founded in 2018 by hepatologist Dr. Stephen Harrison and Gail Hinkson, building on Harrison's work establishing the leading MASH (metabolic dysfunction-associated steatohepatitis) research site in the world before his death in 2024. Headquartered in San Antonio, Texas, the Integrated Research Organization grew from 15 founding network sites to more than 120 clinical trial sites worldwide, specializing in MASH, obesity, and Alzheimer's disease research alongside its core liver disease focus. In May 2025, Summit completed a strategic investment in Houston Research Institute and appointed Dr. Mazen Noureddin as co-chairman of its board. In May 2026, Summit unified with Pinnacle Clinical Research under a single Summit Clinical Research Solutions brand, combining five coordinated platforms spanning site operations, patient recruitment, and early-phase CRO services.

Vantage Clinical Trials

Vantage Clinical Trials operates as a site network that partners with established medical practices to set up and manage clinical research sites within their existing operations, aiming to add research capability with minimal disruption to a practice's day-to-day patient care. Headquartered in the Tampa Bay area of Florida, the company handles study design, contract negotiation, and regulatory management on behalf of partner practices, which retain their focus on treating patients while Vantage runs coordination and compliance. The company positions its approach as reducing the burden on physicians who want to offer clinical trial access without taking on the administrative load of running a dedicated research site themselves. Vantage was registered as a Florida LLC in 2018 and operates from offices in Tampa and Lady Lake, Florida.

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.