Recruitment Activity

Track changes in recruitment statutes, actual versus targeted patient enrollment, and irregularities across 11 event variations so you can accurately assess the feasibility and timeline of any clinical trial.

Selecting Patients

The study is now handpicking patients from a set population determined by investigators. Enrollment is exclusive to invitees, often seen in open-label extensions of prior studies. This recruitment method is rare, used in less than 1% of interventional trials.

Actively Recruiting

The study has transitioned to the active patient enrollment phase. The update might not reflect the exact recruitment start date but serves as a measure of the trial's recruitment duration and progress. This standard progression represents a quarter of all status change updates.

Enrollment Extension

The trial is reverting to “Enrolling by invitation” from “Active, not recruiting”, deviating from its usual path. This change typically characterizes long-term extensions of completed trials exclusive to original participants. It's an atypical trajectory, accounting for about 2% of tracked status changes.

Enrollment Completed

The study has completed its recruitment phase, with all patients enrolled. Though the trial continues, this standard progression is a benchmark for gauging trial health and progress. On average, trials take 2.3 years to finish enrolling, with industry-sponsored trials completing 22% faster.

Population Shift

The trial's recruitment strategy has shifted, either broadening its scope or becoming more selective. This change might indicate a revised study population or hint at a long-term extension. Such changes are rare, occurring in less than 1% of status updates.

Enrollment Increase

The patient enrollment count or target has risen. These shifts can signify various developments, sometimes due to interim analyses re-estimations. Often, they align with primary completion date delays, especially during recruitment, leading to subsequent delays.

Enrollment Decrease

The study's patient enrollment or target has been reduced, usually as the actual count aligns with the initial target during the transition from recruitment to active phases. Such changes might suggest enrollment challenges or broader trial alterations. Notably, 59% of enrollment events involve reductions.

Significant Enrollment Increase

A considerable rise in patient enrollment or target has been noted. Major increases often coincide with primary completion date delays, leading to further postponements. Around 70% of such trials face subsequent delays, with 40% experiencing multiple ones.

Significant Enrollment Decrease

The actual patient enrollment significantly lags behind the target. Falling short might challenge initial efficacy and design assumptions, potentially affecting the trial's outcomes. This pattern might suggest reaching the maximum dose in a dose escalation trial or a transition between trial phases. Notably, 53% of trials with a substantial enrollment decrease that have concluded were terminated early.

Re-entering Recruitment

The trial is re-initiating recruitment, diverging from its expected path. Pauses can arise from planned seamless trials, regulatory holds, or external factors like the Covid-19 pandemic. Sometimes, this involves expanding the study or altering its hypothesis. This is an atypical trajectory, accounting for about 2% of status changes.


The study is regressing to the “Not yet recruiting” status. This deviation often impacts the projected completion timeline and might herald further trial disruptions. Such trajectories are exceedingly rare, occurring in less than 1% of status changes.

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