system
elements
outreach
completion
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Industry
Biotechnology, Digital Health/Therapeutics
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Challenge
A commercial sponsor needed to recruit, enroll, and retain participants for a fully virtual, direct-to-patient observational study, without the manual handoffs between screening and data capture that slow enrollment and cause drop-off.
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Solution
TrialScreen and Castor connected self-screening, consent, enrollment, and ePRO into one real-time-API pipeline, so qualified participants moved from interest to enrolled with no manual lead handoff.
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Result
The study enrolled 2,402 participants and closed enrollment three months ahead of schedule, with 96.7% of enrolled participants actively using the Castor ePRO system and 93.8% completing every study element
The customer’s challenge: how to efficiently enroll and complete a large observational study
The customer, a commercial sponsor, needed to enroll a large population of healthy individuals in Australia preparing for travel to Southeast Asia quickly and within a fixed budget. Recognizing that these individuals would be difficult and expensive to find in a traditional site model, the study was designed to run direct-to-patient which meant outreach, screening, stool samples, and participant reporting all had to happen through technology alone. That approach introduced two risks:
- Scale risk: manually exporting, routing, and following up on thousands of leads would have slowed enrollment and driven up cost.
- Latency risk: the longer a participant waits between self-screening and consent/enrollment, the more likely they are to forget the study or lose interest, at the expense of conversion at the exact moment intent is highest.
The solution: an automated, end-to-end system
TrialScreen and Castor connected their systems through a real-time API so that potential participants could move through a single workflow from first awareness through to ongoing patient-reported outcomes with no manual lead handoff between screening and enrollment:
- A person discovered the study via a TrialScreen awareness campaign, visited the study page, read about the study in plain-language study information, and then chose whether to proceed to check their study fit via the self-screener.
- A participant completed the self-screener on TrialScreen and confirmed interest in the study.
- The real-time API routed contact details into the Castor system automatically, with no manual lead export or import.
- The participant received an outreach to enroll in near real-time, while their interest was still fresh, rather than after the delay that manual follow-up can introduce.
- Patient-reported outcome (ePRO) data capture began once consent was given and continued for the life of the study.
Study outcomes
| Automated workflow | Zero manual lead handoffs, near-real-time follow-up from qualification to enrollment |
| Lead conversion | Nearly 1 in 2 pre-qualified individuals (46%) converted to enrolled participants (5,278 to 2,402). TrialScreen’s self-screening pre-qualified participants, and the automated API handoff removed the delay between screening and enrollment |
| Patient acceptance | 96.7% of enrolled participants (2,324 of 2,402) actively used the Castor ePRO system |
| Study completion | 93.8% of those enrolled successfully completed 100% of study requirements (2,254 of 2,402) |
| Enrollment speed | Closed 3 months ahead of schedule |
Conclusion
The real-time API connection was the how, and closing enrollment three months early was the outcome. By treating awareness, self-screening, consent, enrollment, and patient-reported outcomes as one continuous, automated workflow rather than two tools joined by a manual handoff, TrialScreen and Castor removed the manual delay between interest and enrollment, resulting in enrollment closing three months ahead of target. It’s a model for what direct-to-patient observational studies can look like when every stage of the participant journey runs as a single, connected system.