Across 63 European CTIS head and neck cancer / HNSCC Phase II and Phase III trials, primary endpoint strategy is led by objective response rate (ORR), used in 27 trials (42.9%), followed by safety/tolerability in 20 trials (31.7%) and overall survival (OS) in 16 trials (25.4%). Secondary endpoint strategy is broader and more confirmatory: safety appears in 40 trials (63.5%), OS in 37 trials (58.7%), and both ORR and progression-free survival (PFS) in 29 trials each (46.0%).
The most frequently measured primary endpoint family is ORR in 27 of 63 trials (42.9%). Safety/tolerability is primary in 20 trials (31.7%), OS in 16 trials (25.4%), event-free or disease-free recurrence endpoints in 12 trials (19.0%), and PFS in 10 trials (15.9%).
European HNSCC Phase II/III trials are not anchored to a single dominant primary endpoint. ORR leads because Phase II and basket studies remain response-driven, while OS and PFS become more visible in later-stage and dual-phase trials.
Secondary endpoint measurement is led by safety/tolerability in 40 of 63 trials (63.5%) and OS in 37 trials (58.7%). PFS and ORR each appear in 29 trials (46.0%), while DOR and event-free/disease-free recurrence endpoints each appear in 27 trials (42.9%). Only 1 trial (1.6%) has a populated other/exploratory endpoint bucket.
Secondary endpoint design is where most HNSCC trials absorb regulatory and clinical breadth: safety, survival, RECIST response, durability, pharmacokinetics, biomarkers, and patient-reported outcomes are mostly positioned outside the primary endpoint hierarchy.
The dataset includes 36 Phase II cohort trials (57.1%), 23 Phase III cohort trials (36.5%), and 4 Phase II/III trials (6.3%). ORR is primary in 24 of 36 Phase II trials (66.7%), while OS is primary in 10 of 23 Phase III trials (43.5%). In dual Phase II/III trials, OS and PFS are each primary in 3 of 4 trials (75.0%).
| Phase cohort | Top primary endpoint pattern | Frequency |
|---|---|---|
| Phase II | ORR, then safety/tolerability | 24/36 · 66.7% |
| Phase III | OS, then event-free/recurrence endpoints | 10/23 · 43.5% |
| Phase II/III | OS and PFS co-dominate | 3/4 · 75.0% |
The phase split is clinically intuitive: Phase II prioritizes response signal and safety, while Phase III moves toward OS, PFS, recurrence control, and patient-function endpoints that can support comparative benefit claims in CTIS-submitted European studies.
Most trials are labelled as generic HNSCC/head and neck cancer (56/63, 88.9%). More specific disease contexts include recurrent/metastatic HNSCC in 25 trials (39.7%), multi-tumour basket studies including HNSCC in 17 trials (27.0%), locally advanced HNSCC in 8 trials (12.7%), oropharyngeal/HPV-defined disease in 8 trials (12.7%), and oral/oral cavity SCC in 5 trials (7.9%).
Endpoint choice changes with disease context: recurrent/metastatic HNSCC remains response-heavy, locally advanced disease incorporates event-free/recurrence endpoints, and oral/oropharyngeal settings elevate function, swallowing, QoL, and pain measures.
Modalities with sufficient sample size include monoclonal antibodies in 43 trials (68.3%), small molecules in 30 trials (47.6%), and antibody-drug conjugates (ADCs) in 8 trials (12.7%). ADC trials show the strongest response bias: ORR is primary in 8 of 8 ADC trials (100.0%).
ADC development in European HNSCC remains highly signal-seeking, with ORR present as a primary endpoint in every ADC trial. Monoclonal antibody and small-molecule studies are more heterogeneous, reflecting use across response, survival, safety, and maintenance-style settings.
Across all 63 trials, the median interval from initial CTIS submission to first CTIS authorisation is 94 days. By authorisation year, the median is 61 days for 2024 trials (39 trials), 106 days for 2025 trials (16 trials), and 120.5 days for 2026 trials (8 trials).
For sponsors preparing EU submissions in head and neck cancer, the CTIS timing signal is operationally important: newer 2025–2026 authorisations show longer median submission-to-authorisation intervals than the 2024 cohort.
Beyond endpoint frequency, the same CTIS dataset answers whether primary endpoint strategies are simple or complex, how often RECIST is used, and whether patient-centred outcomes are positioned as primary or secondary endpoints.
35 trials (55.6%) use one primary endpoint, 9 trials (14.3%) use two, 14 trials (22.2%) use three or more, and 5 trials (7.9%) have no populated primary endpoint bucket.
RECIST or iRECIST appears in primary endpoints in 32 trials (50.8%) and in secondary endpoints in 32 trials (50.8%).
QoL, patient-reported, pain, swallowing, or functional endpoints appear in the primary bucket in 6 trials (9.5%) and in the secondary bucket in 20 trials (31.7%).
The endpoint architecture is more complex than a simple OS/PFS/ORR hierarchy: 22.2% of trials use at least three primary endpoints, RECIST remains central, and patient-centred measures are common but mostly secondary.
ORR = objective response rate; OS = overall survival; PFS = progression-free survival; DOR = duration of response; DCR = disease control rate; QoL = quality of life; PRO = patient-reported outcome; RECIST = Response Evaluation Criteria in Solid Tumors; CTIS = Clinical Trials Information System for EU clinical trial submission and authorisation workflows; HNSCC = head and neck squamous cell carcinoma; ADC = antibody-drug conjugate.