Across 401 unique lung cancer trials with Phase I, Phase II or Phase III activity authorized from 2024 to 2026, 201 trials used at least one CRO or CRO-like operational vendor, equal to 50.1% of the cohort. CRO use was strongly tied to operational complexity: only 24 of 136 single-country trials used CROs (17.6%), compared with 40 of 42 trials involving 10 or more countries (95.2%). The clearest site-count threshold was 21 or more sites, where CRO use rose to 123 of 165 trials (74.5%).
CRO support was present in 201 of 401 lung cancer trials (50.1%). CRO use was stable across authorization years: 127 of 258 trials in 2024 (49.2%), 54 of 105 in 2025 (51.4%) and 20 of 38 in 2026 (52.6%).
Across all lung cancer phases, CRO use was not primarily a year-by-year trend. It was more strongly explained by trial complexity, especially countries and sites.
CRO use was materially higher in Phase III-containing trials than in earlier-stage trials. CROs supported 83 of 136 Phase III-containing trials (61.0%), compared with 70 of 157 Phase II-containing trials (44.6%) and 48 of 108 Phase I-only trials (44.4%).
The phase signal is clear: CRO utilization rises once lung cancer programs enter Phase III-level execution, where country footprint, site footprint and vendor coordination typically expand.
The strongest complexity signal was country count. CRO use rose from 24 of 136 single-country trials (17.6%) to 58 of 109 trials with 2–4 countries (53.2%), 79 of 114 trials with 5–9 countries (69.3%) and 40 of 42 trials with 10 or more countries (95.2%). This makes 10 or more countries the clearest high-complexity CRO threshold.
| Country-count band | CRO trials | Share |
|---|---|---|
| 1 country | 24/136 | 17.6% |
| 2–4 countries | 58/109 | 53.2% |
| 5–9 countries | 79/114 | 69.3% |
| 10+ countries | 40/42 | 95.2% |
The first major inflection appears immediately after single-country execution: CRO use jumps from 17.6% in single-country trials to 53.2% in 2–4 country trials. At 10 or more countries, CRO use becomes near-universal.
Site count also strongly predicted CRO utilization. CRO use was 27 of 90 trials with 1–5 sites (30.0%) and 51 of 146 trials with 6–20 sites (34.9%). It rose sharply at 21–50 sites, where 77 of 110 trials used CROs (70.0%), and reached 46 of 55 trials with 51 or more sites (83.6%).
The site-count inflection is around 21 sites. Trials with 21 or more sites used CROs in 123 of 165 cases (74.5%), compared with 78 of 236 trials below 21 sites (33.1%).
Patient count predicted CRO use, but less consistently than countries or sites. CRO support appeared in 49 of 133 trials with 1–50 participants (36.8%), 84 of 160 trials with 51–150 participants (52.5%), 60 of 91 trials with 151–400 participants (65.9%) and 8 of 17 trials with 401 or more participants (47.1%).
| Participant-count band | CRO trials | Share |
|---|---|---|
| 1–50 participants | 49/133 | 36.8% |
| 51–150 participants | 84/160 | 52.5% |
| 151–400 participants | 60/91 | 65.9% |
| 401+ participants | 8/17 | 47.1% |
Patient count matters, but country and site count are stronger CRO-use predictors. The most useful patient-count threshold is around 151–400 participants, where CRO use reaches 65.9%.
IQVIA was the most recurrent CRO group, appearing in 60 of 401 trials (15.0%) and 60 of 201 CRO-supported trials (29.9%). It was followed by PPD/Thermo Fisher in 58 trials, Clario/Bioclinica/ERT in 54, Parexel in 52 and ICON in 51.
| CRO / vendor group | Trials | Share of all trials |
|---|---|---|
| IQVIA | 60 | 15.0% |
| PPD / Thermo Fisher | 58 | 14.5% |
| Clario / Bioclinica / ERT | 54 | 13.5% |
| Parexel | 52 | 13.0% |
| ICON | 51 | 12.7% |
| Almac | 41 | 10.2% |
| Labcorp / Q2 Solutions | 36 | 9.0% |
The top CRO layer combines full-service CROs with imaging, lab, eCOA and trial-technology vendors. Lung cancer trial outsourcing is therefore better understood as an operational vendor ecosystem, not a single-CRO assignment.
IQVIA, PPD/Thermo Fisher, Clario/Bioclinica/ERT, Parexel and ICON all appeared across 2024, 2025 and 2026. IQVIA appeared in 33 trials in 2024, 18 in 2025 and 9 in 2026; PPD/Thermo Fisher appeared in 34, 17 and 7 respectively.
| CRO / vendor group | 2024 | 2025 | 2026 | Total |
|---|---|---|---|---|
| IQVIA | 33 | 18 | 9 | 60 |
| PPD / Thermo Fisher | 34 | 17 | 7 | 58 |
| Clario / Bioclinica / ERT | 34 | 10 | 10 | 54 |
| Parexel | 34 | 8 | 10 | 52 |
| ICON | 29 | 17 | 5 | 51 |
CRO-supported trials accounted for 6,987 of 10,040 country-level sites (69.6%) and 27,722 of 51,248 country-level participants (54.1%). Median country count was 5 in CRO-supported trials versus 1 in trials without CRO support. Median site count was 26 versus 11, and median participant count was 100 versus 63.5.
CRO use is most strongly linked to breadth of execution. CRO-backed trials carried nearly 70% of all country-level sites despite representing 50.1% of unique trials.
Spain led CRO-supported lung cancer trial activity with 1,603 country-level sites and 6,770 country-level participants. France followed with 1,080 sites, Italy with 1,060, Germany with 767 and Poland with 531. The top five countries accounted for 5,041 of 6,987 CRO-supported sites (72.1%).
CRO-backed lung cancer execution is highly concentrated in the large European oncology trial markets. Spain is the clear leading site market in the CRO-supported footprint.
United States-based sponsors accounted for 92 of 201 CRO-supported lung cancer trials (45.8%). Germany followed with 23 trials (11.4%), Sweden with 19 (9.5%), Switzerland with 18 (9.0%) and Ireland with 12 (6.0%).
| Sponsor country | Trials | Share |
|---|---|---|
| United States | 92 | 45.8% |
| Germany | 23 | 11.4% |
| Sweden | 19 | 9.5% |
| Switzerland | 18 | 9.0% |
| Ireland | 12 | 6.0% |
CRO-supported trials had a median of 8 listed third parties per trial and an average of 9.0, compared with a median of 0 and an average of 0.7 in trials without CRO support. The highest observed third-party count in a CRO-supported trial was 35.
CRO-supported lung cancer trials are not only larger; they are vendor-dense. The CRO label often marks a broader execution stack involving imaging, central labs, technology, recruitment and monitoring.
The strongest predictor of CRO utilization in European lung cancer trials is not year and not patient count alone. It is geographic and site complexity. CRO use rises sharply once a trial moves beyond a single-country design, becomes dominant at 5–9 countries, and becomes near-universal at 10 or more countries.
For sponsors planning European lung cancer trials, the practical outsourcing threshold is visible: once the trial reaches roughly 21 sites or 10 countries, CRO involvement becomes the norm rather than the exception. The most recurrent CRO/vendor groups across this environment are IQVIA, PPD/Thermo Fisher, Clario/Bioclinica/ERT, Parexel and ICON.
CRO means contract research organization. CTIS means Clinical Trials Information System. CRO-supported means the sponsor record listed CRO presence as “Yes.” Country-level sites and participants are summed from the participating countries listed for each trial. Phase III-containing means the trial stage included Phase III; Phase II-containing means it included Phase II but not Phase III; Phase I-only means the listed stage did not include Phase II or Phase III.