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European endpoint evidence

Clinical trial endpoints in Europe: what Phase II and III trials actually measure

Endpoint selection in European trials is structured rather than random. Safety is one of the most common measurement families across therapeutic areas, but the primary endpoint that carries the trial changes sharply by phase and disease.

Phase II frequently leans toward activity, response and safety, while Phase III more often shifts toward survival, progression and other confirmatory outcomes. The strongest designs are disease-specific: remission and endoscopy in IBD, HbA1c in diabetes, FVC in fibrosis, exacerbations in asthma/COPD, and cognition plus biomarkers in Alzheimer’s disease.
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What the evidence shows

Recurring findings across European trials

1

Safety is ubiquitous, but it is rarely the whole endpoint strategy

Safety or tolerability appeared in 76.7% of ovarian cancer trials, 77.8% of colorectal cancer trials, 76.5% of breast cancer trials, 70.2% of prostate cancer trials, 63.0% of infectious-disease trials, 62.8% of respiratory trials and 60.7% of Alzheimer’s/dementia trials. Yet the dominant primary endpoint often came from a disease-efficacy measure rather than safety itself.

EvidenceWhich Endpoints Are Measured Most Often in European Phase II & III Ovarian Cancer Trials? · Which endpoints dominate European Phase II and III colorectal cancer trials? · Which Endpoints Are Measured Most Often in European Phase II & III Breast Cancer Trials? · Which Endpoints Are Measured Most Often in European Phase II & III Prostate Cancer Trials? · Which Endpoints Are Measured Most Often in European Infectious Disease Phase II and Phase III Trials? · Which Endpoints Are Measured Most Often in European Respiratory Phase II and Phase III Trials? · Which Endpoints Are Measured Most Often in European Alzheimer’s and Dementia Phase II & III Trials?
2

Phase II is more response-led; Phase III becomes more confirmatory

In lung cancer, ORR/overall response was primary in 59.3% of Phase II records, while Phase III shifted to PFS as primary in 44.0% and OS in 36.7%. Colorectal cancer showed the same broad transition: Phase II leaned toward safety and response packages, while Phase III placed more weight on survival, disease-free/relapse-free survival and quality of life.

EvidenceWhich Endpoints Are Measured Most Often in European Phase II & III Lung Cancer Trials? · Which endpoints dominate European Phase II and III colorectal cancer trials?
3

PFS is a recurring primary anchor in later-stage oncology, but not universally

PFS was the leading primary endpoint family in ovarian cancer at 38.4% and in breast cancer at 29.2%. In Phase III lung cancer, PFS was primary in 44.0% and OS in 36.7%. HNSCC differed: ORR was the most common primary family at 42.9%, showing why indication and phase need to be considered together.

EvidenceWhich Endpoints Are Measured Most Often in European Phase II & III Ovarian Cancer Trials? · Which Endpoints Are Measured Most Often in European Phase II & III Breast Cancer Trials? · Which Endpoints Are Measured Most Often in European Phase II & III Lung Cancer Trials? · Which Endpoints Are Measured Most Often in European Phase II & III Head and Neck Cancer Trials?
4

The disease often dictates the endpoint family more strongly than the phase label alone

IBD was built around clinical remission, used in 69% of trials and as a primary endpoint in 52%. Respiratory programmes split by disease: FVC dominated pulmonary fibrosis/ILD, exacerbations dominated asthma/COPD, and tumour response plus survival dominated lung cancer. In diabetes, HbA1c/glycaemic control became the leading Phase III signal, appearing in 53.2% of Phase III records. Alzheimer’s trials combined cognition, function, imaging and blood/CSF biomarkers rather than relying on one universal efficacy measure.

EvidenceWhich Endpoints Are Measured Most Often in European Inflammatory Bowel Disease Phase II & III Trials? · Which Endpoints Are Measured Most Often in European Respiratory Phase II and Phase III Trials? · Which Endpoints Are Measured Most Often in European Phase II & III Diabetes Mellitus Trials? · Which Endpoints Are Measured Most Often in European Alzheimer’s and Dementia Phase II & III Trials?
5

Secondary endpoints are broader and more standardized than primary endpoints

In lung cancer, OS, PFS and safety each appeared as secondary endpoints in roughly six in ten records, while ORR/response was secondary in 64.2%. Breast cancer used OS as a secondary endpoint in 66.9% of trials. Ovarian cancer layered safety in 61.6%, OS in 55.8% and PFS in 53.5% as secondary measures. The recurring pattern is a focused primary question supported by a broader confirmatory package.

EvidenceWhich Endpoints Are Measured Most Often in European Phase II & III Lung Cancer Trials? · Which Endpoints Are Measured Most Often in European Phase II & III Breast Cancer Trials? · Which Endpoints Are Measured Most Often in European Phase II & III Ovarian Cancer Trials?
6

Patient-relevant outcomes become especially visible in chronic and confirmatory settings

PROs, symptoms or quality-of-life measures appeared in 54.8% of respiratory trials and in 52.9% of prostate cancer trials. Colorectal Phase III also shifted more strongly toward quality-of-life outcomes than Phase II. These measures are not generic additions: their role rises where symptom burden, function and long-term benefit are central to the treatment question.

EvidenceWhich Endpoints Are Measured Most Often in European Respiratory Phase II and Phase III Trials? · Which Endpoints Are Measured Most Often in European Phase II & III Prostate Cancer Trials? · Which endpoints dominate European Phase II and III colorectal cancer trials?

What this changes in trial planning

  • Benchmark primary and secondary endpoint roles separately; frequency across any role can hide the actual hierarchy.
  • Use phase as a starting point, then let disease biology and treatment intent determine the endpoint family.
  • For oncology, explicitly test whether the programme should be response-led, PFS-led or OS-led rather than copying a generic package.
  • Use PROs, biomarkers and functional measures where they answer a clinically relevant decision question, not merely because peers include them.

Scope note. This page synthesizes findings from separate Trial Agents analyses of European CTIS cohorts. Each statistic remains tied to the phase, disease, modality and time window of its underlying analysis. Cross-cohort patterns are used as planning signals, not pooled estimates or causal claims.

Underlying evidence

Read the analyses behind these findings

More evidence

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