Clinical Trial Intelligence

Which Endpoints Are Measured Most Often in European Respiratory Phase II and Phase III Trials?

5 July 2026

Across 239 CTIS-authorized European respiratory Phase II and Phase III trials, safety and tolerability were the most common endpoint family, appearing in 150/239 trials (62.8%). Patient-reported outcomes, symptoms, and quality-of-life measures followed in 131/239 trials (54.8%), while biomarker or diagnostic endpoints appeared in 107/239 trials (44.8%). Endpoint selection was strongly disease-shaped: FVC dominated pulmonary fibrosis/ILD, exacerbations dominated asthma and COPD, and RECIST/RANO response plus survival dominated lung cancer.

Trials
239
Phase II: 120; Phase III: 119
Top endpoint
62.8%
Safety/tolerability, 150/239
Top secondary
56.7%
PROs/QoL, 119/210
Median CTIS time
104d
Submission to first authorization

Safety, PROs, and biomarkers are the dominant respiratory endpoint families

At trial level, safety/tolerability appeared in 150/239 trials (62.8%), patient-reported outcomes (PROs), symptoms, or quality of life (QoL) in 131/239 (54.8%), and biomarkers/diagnostics in 107/239 (44.8%). A trial could count once per endpoint family if that endpoint appeared in any primary, secondary, or exploratory role.

Trial-level endpoint family prevalence
Safety / tolerability
62.8%
PROs, symptoms & QoL
54.8%
Biomarkers / diagnostics
44.8%
Overall survival / mortality
40.2%
Clinical worsening / hospitalization
36.8%
PK / dose exposure
25.1%
FVC / ppFVC
20.9%
FEV1 / airflow spirometry
20.5%
Exacerbations / loss of control
19.7%
Tumour response / RECIST-RANO
15.9%
Percentage of 239 respiratory Phase II and Phase III trials
Interpretation

Respiratory Phase II/III endpoint design is not defined by one pulmonary physiology measure. Safety, PRO/QoL, biomarkers, survival, and clinical worsening appear more often than FEV1 or FVC because the CTIS respiratory cohort spans airway disease, fibrotic lung disease, lung cancer, infection, neonatal/critical care, and pulmonary vascular disease.

Primary endpoints are fragmented, while secondary endpoints concentrate around PROs, safety, and biomarkers

Among 230 trials with primary endpoint entries, safety/tolerability led with 51/230 trials (22.2%), followed by survival/mortality in 33/230 (14.3%), PROs/QoL in 29/230 (12.6%), and FVC/ppFVC in 25/230 (10.9%). Among 210 trials with secondary endpoint entries, PROs/QoL appeared in 119/210 (56.7%), safety in 114/210 (54.3%), and biomarkers/diagnostics in 99/210 (47.1%). Exploratory endpoints were present in 8/239 trials (3.3%).

Top endpoint families by role
Endpoint family
Primary
Secondary
Exploratory
Safety / tolerability
22.2%
54.3%
37.5%
PROs, symptoms & QoL
12.6%
56.7%
50.0%
Biomarkers / diagnostics
10.0%
47.1%
50.0%
Overall survival / mortality
14.3%
40.0%
37.5%
Clinical worsening / hospitalization
7.0%
40.5%
25.0%
FVC / ppFVC
10.9%
21.4%
12.5%
Denominators: primary n=230, secondary n=210, exploratory n=8
Interpretation

Primary endpoints reflect disease-specific regulatory logic: safety for early or high-risk studies, FVC for fibrotic lung disease, exacerbations for obstructive airway disease, and response/survival for lung cancer. Secondary endpoints are broader and repeatedly add patient experience, safety, biomarker, and clinical-worsening dimensions.

Phase II emphasizes safety and PK more; Phase III shifts toward PROs and clinical events

In Phase II trials (n=120), safety/tolerability appeared in 86/120 trials (71.7%), PROs/QoL in 62/120 (51.7%), biomarkers in 57/120 (47.5%), and PK/dose exposure in 41/120 (34.2%). In Phase III trials (n=119), PROs/QoL led with 69/119 trials (58.0%), followed by safety in 64/119 (53.8%), biomarkers and clinical worsening in 50/119 each (42.0%), and survival/mortality in 43/119 (36.1%).

Endpoint prevalence by phase
Phase II
Phase III
Safety / tolerability
PROs, symptoms & QoL
Biomarkers / diagnostics
Clinical worsening / hospitalization
PK / dose exposure
Exacerbations / loss of control
Percentage of trials within phase cohort
Interpretation

The Phase II respiratory portfolio remains more dose- and safety-discovery oriented, with PK/dose exposure twice as common as in Phase III. Phase III trials more often add clinical-worsening, hospitalization, and patient-experience endpoints, consistent with confirmatory outcome packages.

Disease area is the strongest driver of endpoint choice

The largest disease groups were lung cancer (38/239, 15.9%), respiratory infection (32/239, 13.4%), pulmonary fibrosis/ILD (29/239, 12.1%), asthma (26/239, 10.9%), and COPD/emphysema (25/239, 10.5%). In disease groups with at least 8 trials, the dominant endpoint families were sharply different: tumour response and survival in lung cancer, FVC in pulmonary fibrosis/ILD, infection/safety endpoints in respiratory infections, exacerbations and FEV1 in asthma/COPD, and 6MWD/PVR/functional class in pulmonary hypertension.

Disease-specific endpoint signatures
Lung cancer
38 trials
86.8%
Safety/tolerability; survival 84.2%, tumour response 76.3%
Pulmonary fibrosis / ILD
29 trials
93.1%
FVC/ppFVC; clinical worsening and PRO/QoL each 55.2%
Respiratory infection
32 trials
75.0%
Safety/tolerability; biomarkers 59.4%, PRO/QoL 50.0%
Asthma
26 trials
65.4%
PRO/QoL; exacerbations 57.7%, FEV1 53.8%
COPD / emphysema
25 trials
68.0%
PRO/QoL; exacerbations 56.0%, clinical worsening 48.0%
Pulmonary hypertension
11 trials
81.8%
6MWD/PVR/functional class; biomarkers 63.6%
Disease groups with at least 8 trials; top family shown with supporting secondary families
Interpretation

The broad respiratory label hides distinct development logics. Fibrosis studies are physiology-led, asthma and COPD are exacerbation and symptom-led, pulmonary hypertension is functional/hemodynamic-led, and lung cancer is oncology-led despite being captured inside the respiratory CTIS cohort.

Primary endpoints show clear disease-specific anchors

Among disease groups with at least 8 trials, the most frequent primary endpoint family was FVC/ppFVC in pulmonary fibrosis/ILD (19/29, 65.5%), PRO/QoL in upper-airway allergy/CRS (7/8, 87.5%), 6MWD/PVR/functional class in pulmonary hypertension (6/11, 54.5%), safety in cystic fibrosis (6/10, 60.0%), tumour response in lung cancer (16/38, 42.1%), exacerbations in COPD/emphysema (10/25, 40.0%), and exacerbations in asthma (8/26, 30.8%).

Primary endpoint anchor by disease
Upper-airway allergy / CRS
87.5%
Pulmonary fibrosis / ILD
65.5%
Cystic fibrosis
60.0%
Pulmonary hypertension
54.5%
Lung cancer
42.1%
COPD / emphysema
40.0%
Asthma
30.8%
Bar shows prevalence of the leading primary endpoint family within each disease group
Interpretation

Primary endpoint selection is highly anchored where disease conventions are mature: FVC for fibrosis, 6MWD/PVR/functional class for pulmonary hypertension, RECIST/RANO response for lung cancer, and exacerbation outcomes for COPD and asthma. Safety becomes a primary anchor mainly where the studied population or modality is higher risk.

Modality differences are visible where trial counts are sufficient

Five modality groups had at least 20 trials: small molecules (99/239, 41.4%), small molecule plus monoclonal antibody combinations (31/239, 13.0%), monoclonal antibodies (29/239, 12.1%), protein/peptide therapies (21/239, 8.8%), and mixed combinations (20/239, 8.4%). Small molecule trials most often used safety (63/99, 63.6%) and PRO/QoL endpoints (58/99, 58.6%); monoclonal antibody trials most often used PRO/QoL endpoints (20/29, 69.0%) and had immunogenicity/ADA-nAb endpoints in 9/29 trials (31.0%).

Modality groups with at least 20 trials
Small molecule
99 trials
Safety 63.6%; PRO/QoL 58.6%; clinical worsening 52.5%
Small molecule + mAb
31 trials
Safety 77.4%; survival 54.8%; tumour response 54.8%
Monoclonal antibody
29 trials
PRO/QoL 69.0%; biomarkers 44.8%; clinical worsening 44.8%
Protein / peptide
21 trials
Safety 66.7%; PRO/QoL 57.1%; biomarkers 38.1%
mAb = monoclonal antibody; ADA = anti-drug antibody; nAb = neutralizing antibody
Interpretation

The modality signal is partly confounded by disease mix, but still operationally useful: small molecules and combinations carry broad safety packages, mAbs add immunogenicity and biomarker layers, and oncology-style small molecule plus mAb combinations concentrate response and survival endpoints.

Adjacent question: how long did CTIS respiratory trials take from submission to first authorization?

Across all 239 respiratory Phase II/III trials, the median time from initial CTIS submission to first CTIS authorization was 104 days. Phase II trials had a median of 106 days, and Phase III trials had a median of 102 days. By CTIS authorization year, the median was 82 days for 2024-authorized trials, 112 days for 2025-authorized trials, and 114 days for 2026-authorized trials.

CTIS submission-to-authorization timing
All trials
104
days
Phase II
106
days
Phase III
102
days
2025 auth.
112
days
2026 auth.
114
days
CTIS = Clinical Trials Information System; timing uses initial CTIS submission date to first CTIS authorization date
Interpretation

The CTIS timing pattern suggests that endpoint complexity is not the only operational variable: both Phase II and Phase III respiratory submissions had similar authorization medians, while the authorization-year cohorts shifted upward after 2024. This is useful context for planning EU respiratory submissions under CTIS.

Endpoint definitions used in this report

Endpoint families were counted at trial level. A trial could contribute to multiple endpoint families if different endpoint measures appeared in its primary, secondary, or exploratory endpoint text.

FVC / ppFVC: forced vital capacity, including absolute or percent-predicted FVC.
FEV1: forced expiratory volume in 1 second, usually measured by spirometry.
PRO/QoL: patient-reported outcomes, symptoms, questionnaires, and quality-of-life scales.
RECIST/RANO: imaging response frameworks used mainly in oncology or brain-metastasis trials.
PFS: progression-free survival.
PK: pharmacokinetics, including AUC, Cmax, Tmax, Ctrough, and half-life.
6MWD: six-minute walk distance.
PVR: pulmonary vascular resistance, used in pulmonary hypertension trials.
ADA/nAb: anti-drug antibodies and neutralizing antibodies.
CTIS: EU Clinical Trials Information System.