The eClinical platform a doctor built because the software he needed did not exist. Now it runs clinical trials in more than 90 countries.
Castor is a health-technology company that makes software for running clinical trials. Its cloud platform gathers the pieces of a study that have traditionally lived in separate, often paper-bound systems - collecting data, obtaining patient consent, recording outcomes, and pulling in information from hospitals, wearables and labs - and puts them in one place, from recruitment through to analysis.
The company's own summary of its purpose is a single sentence: solve the world's healthcare challenges with research data. In practice that means electronic data capture (EDC), electronic informed consent (eConsent), electronic clinical outcome assessment (eCOA/ePRO), decentralized trial tooling, and a real-world evidence layer, all delivered as B2B software.
Castor was built in 2012 by Dr. Derk Arts, a medical doctor who taught himself software development during his MD and needed a better way to capture data for his own PhD research. That origin - a researcher solving his own problem - still shapes the product's bias toward being usable by clinicians rather than only by specialist data managers.
Today the platform is used by more than 223,000 registered researchers and has supported over 15,000 studies covering upwards of 8 million patients across 90-plus countries, from large contract research organizations to single academic labs.
"Built by a researcher, for researchers - because there was no affordable, user-friendly way to capture and manage medical research data."
Bringing a treatment to patients depends on trials, and trials move at the speed of their data. Historically that has meant fragmented systems, manual transcription, in-person visits on rigid schedules, and data locked away in silos that no one reuses once a study ends. Each of those frictions adds cost and time - and time in research is measured in patients waiting for answers.
Castor attacks that friction on two fronts. First, speed of setup: a low-code eCRF builder lets teams design a study and deploy low-complexity trials in as little as three to four weeks, cutting build times by up to 63% by the company's account. Second, reach: direct-to-patient tools let participants enroll, consent and share data from home, so a trial no longer requires everyone to travel to a site.
The company is also a vocal advocate for FAIR data - findable, accessible, interoperable and reusable - the idea that research data should be usable again after a study closes, so the next trial starts smarter than the last.
Low-code eCRF builder claims up to 63% faster setup and 3-4 week deployment for simple studies.
Decentralized and hybrid tooling lets patients enroll and consent remotely, widening the participant pool.
A FAIR-data approach and RWE layer make trial data reusable across studies instead of stranded.
API-driven electronic data capture and clinical data management with a low-code eCRF builder.
Remote and in-person electronic consent with a continuous flow and OTP login to cut drop-off.
Clinical outcome assessments, patient-reported outcomes and digital diaries via web and mobile.
Direct-to-patient enrollment, consent and data sharing for virtual and hybrid studies.
Integrates EHR, wearable, lab and device data into a single trial data environment.
AI data extraction built with Google Cloud on Gemini and Vertex AI - targeting up to 50% less manual effort in Phase 2/3.
The eClinical market is crowded and includes heavyweights such as Medidata, Veeva and Oracle, alongside academic staples like REDCap and OpenClinica. Castor's positioning is less about out-featuring the giants and more about who the product is designed for: it leans self-service and researcher-friendly, so a smaller team can stand up a study without a large implementation budget.
That heritage - a physician building the tool he wished existed - is the throughline. Where much enterprise trial software assumes a dedicated data-management department, Castor pushes usability toward the people actually running the research, then layers in the regulatory rigor (GDPR, HIPAA, ISO 27001, ISO 9001) that sponsors require.
Its practical, partnership-led approach to AI fits the same pattern: Castor Catalyst is framed as removing manual grunt work rather than replacing human judgment.
Figures as reported by Castor; treat as company-stated, not independently audited.
Castor sells its platform as B2B software on a subscription and usage basis. Its customers span the research spectrum: pharmaceutical and biotech sponsors, contract research organizations (CROs), medical-device companies, and academic and hospital research teams. A self-service model lets smaller groups onboard directly, while larger, multi-study enterprise contracts and a dedicated CRO partnership program - launched in 2022 to accelerate decentralized-trial adoption - drive the bigger deals.
Public estimates put annual revenue in the region of $28 million with a team of roughly 290 people, split between its U.S. base at 175 Varick Street in New York and its Amsterdam roots. The company's scale claims - 15,000-plus studies, 8 million-plus patients, 223,000-plus researchers - describe a broad, geographically distributed user base rather than a handful of marquee accounts.
The 2021 Series B was earmarked for scaling direct-to-patient trials globally, expanding into Asia-Pacific, and doubling down on the U.S. footprint. Castor's board is chaired by Frans van Houten, the former CEO of Philips - a signal of how seriously incumbent healthcare views the shift to software-run trials.
Dr. Derk Arts builds the platform to solve his own clinical data capture problems during his PhD.
Early venture funding from INKEF Capital and Two Sigma Ventures fuels expansion beyond EDC.
Castor raises a Series A and expands into real-world evidence and multi-source data.
Direct-to-patient tooling positions Castor for the pandemic-era surge in remote trials.
Eight Roads Ventures and F-Prime Capital lead a round to scale direct-to-patient trials.
An AI data-extraction platform built with Google Cloud brings practical AI into Phase 2/3 studies.
OTP login becomes the default in eConsent; Castor joins the C-Path eCOA Consortium.