Clinical Trial Intelligence

Which Endpoints Are Measured Most Often in European Phase II & III Ovarian Cancer Trials?

9 July 2026

Across 86 European CTIS-authorized ovarian, fallopian tube, and primary peritoneal cancer Phase II/III trial records, safety endpoints were the most widely measured endpoint family, appearing in 66 trials (76.7%). Progression-free survival (PFS) was the dominant primary endpoint family at 33 trials (38.4%), while secondary endpoint strategy was broader: safety appeared in 53 trials (61.6%), overall survival (OS) in 48 (55.8%), and PFS in 46 (53.5%).

Included trials
86
EU CTIS records, 2024–2026
Top endpoint family
66
Safety / AEs / tolerability, 76.7%
Top primary endpoint
33
PFS, 38.4% of all trials
Top secondary endpoint
53
Safety / AEs / tolerability, 61.6%

Safety, PFS, and OS form the core endpoint backbone

At trial level, safety / adverse events (AEs) / tolerability appeared in 66 of 86 trials (76.7%), followed by PFS in 60 trials (69.8%) and OS in 55 trials (64.0%). Objective response rate (ORR) was also common, appearing in 39 trials (45.3%).

Endpoint family present in any role, % of 86 trials
Safety / AEs / tolerability76.7%
PFS69.8%
OS64.0%
ORR45.3%
QoL / PRO37.2%
DOR36.0%
Endpoint families counted once per trial when present in primary, secondary, or exploratory/other endpoints.
Interpretation

European ovarian cancer trials are not endpoint-sparse: 66/86 trials include safety, 60/86 include PFS, and 55/86 include OS, indicating that most CTIS submissions combine tolerability, disease-control, and survival evidence rather than relying on one endpoint family alone.

PFS is the leading primary endpoint, ahead of safety and ORR

Structured primary endpoints appeared in 80 of 86 trials (93.0%). PFS was used as a primary endpoint family in 33 trials (38.4%), followed by safety / AEs / tolerability in 27 trials (31.4%) and ORR in 18 trials (20.9%).

Primary endpoint family, % of 86 trials
Endpoint family Trials %
PFS33/8638.4%
Safety / AEs / tolerability27/8631.4%
ORR18/8620.9%
PD / biomarker / translational10/8611.6%
OS6/867.0%
Primary endpoint family counted once per trial.
Interpretation

Primary endpoint design is anchored in disease-control evidence: PFS appeared 1.8 times as often as ORR as a primary endpoint family (33 vs 18 trials). Safety remained prominent because Phase I/II and dose-expansion designs were included in the Phase II CTIS cohort.

Secondary endpoint packages are broader and survival-heavy

Secondary endpoints appeared in 71 of 86 trials (82.6%), covering 424 endpoint items. Safety / AEs / tolerability appeared as a secondary endpoint family in 53 trials (61.6%), OS in 48 (55.8%), PFS in 46 (53.5%), ORR in 32 (37.2%), and duration of response (DOR) in 30 (34.9%).

Secondary endpoint family, % of 86 trials
61.6%
Safety / AEs — 53/86
55.8%
OS — 48/86
53.5%
PFS — 46/86
37.2%
ORR — 32/86
34.9%
DOR — 30/86
33.7%
QoL / PRO — 29/86
Secondary endpoint family counted once per trial.
Interpretation

The secondary layer is where ovarian cancer CTIS submissions add survival maturity, response durability, patient-reported outcomes, and safety support: OS appears in 48/86 trials as secondary compared with only 6/86 as primary.

Exploratory/other endpoint fields are uncommon but biomarker- and PRO-oriented

Dedicated exploratory/other endpoint fields appeared in 7 of 86 trials (8.1%), covering 8 endpoint items. QoL / patient-reported outcomes (PROs) and PD / biomarker / translational endpoints each appeared in 3 trials (3.5%), while PFS, OS, and safety each appeared in 2 trials (2.3%).

Exploratory/other endpoint family, % of 86 trials
QoL / PRO3/863.5%
PD / biomarker / translational3/863.5%
Safety / AEs / tolerability2/862.3%
PFS2/862.3%
OS2/862.3%
Exploratory/other endpoint family counted once per trial.
Interpretation

Exploratory evidence is present but not structurally dominant in the CTIS endpoint fields: only 7/86 trials used dedicated exploratory/other fields, with biomarker and PRO signals more common than additional survival endpoints.

Phase III shifts toward PFS as the primary endpoint

The cohort included 36 Phase II trials (41.9%), 30 Phase III trials (34.9%), 18 Phase I/II trials (20.9%), and 2 Phase II/III bridge trials (2.3%). In pure Phase III trials, PFS appeared as a primary endpoint family in 18/30 trials (60.0%), compared with 12/36 pure Phase II trials (33.3%).

Primary endpoint family by phase, % within