Endpoints

This page is reference information compiled from the cited sources. It is not medical advice. For any decision about health, diagnosis or care, consult a qualified professional.

What it is

Clinical endpoints are outcome measures referring to the occurrence of a disease, symptom, sign, or laboratory abnormality that constitutes a target outcome in clinical research trials. The term may also refer to any disease or sign that strongly motivates withdrawal of an individual or entity from the trial, often termed a humane endpoint. In a general sense, a clinical endpoint is included in the entities of interest in a trial. Once a patient reaches the endpoint, he or she is generally excluded from further experimental intervention. A clinical trial will usually define a primary endpoint as a measure considered success of the therapy being trialled. Secondary endpoints are additional endpoints, preferably pre-specified, for which the trial may not be powered.

Key facts

The primary endpoint of a clinical trial is the endpoint for which the trial is powered. The results of a clinical trial indicate the number of people enrolled who reached the pre-determined clinical endpoint during the study interval compared with the overall number enrolled. When an experiment involves a control group, the proportion reaching the endpoint after an intervention is compared with the proportion in the control group who reached the same endpoint. Clinical endpoints can be obtained from different modalities, such as behavioural or cognitive scores, or biomarkers from Electroencephalography, MRI, PET, or biochemical biomarkers. In cancer research, common endpoints include discovery of recurrence or metastasis, onset of symptoms, hospitalization, change in pain medication requirement, onset of toxicity, requirement of salvage therapy, or death. These are often expressed as a period of time, such as survival duration in months, with the median frequently used. Surrogate endpoints are trial endpoints that have outcomes that substitute for a clinical endpoint, often because studying the clinical endpoint is difficult. A combined endpoint merges a variety of outcomes into one group, such as chest pain, myocardial infarction, or death.

When to seek professional help

The source text associates professional care with situations defined as clinical endpoints or outcomes within a trial. These include the occurrence of disease, a symptom, a sign, or a laboratory abnormality that constitutes a target outcome. Professional intervention is motivated when an individual reaches a humane endpoint, defined as the point at which pain or distress is terminated, minimized, or reduced, which may necessitate withdrawal from a trial. The source describes situations such as the discovery of local recurrence, regional metastasis, or distant metastasis in cancer. It mentions the onset of symptoms, hospitalization, or an increase or decrease in pain medication requirement. The occurrence of toxicity or the requirement of salvage chemotherapy, surgery, or radiotherapy are also noted. The source defines serious adverse events that warrant attention, including outcomes resulting in death, being life-threatening, requiring inpatient hospitalization, causing significant incapacity, or involving congenital anomalies. A combined endpoint may constitute a threshold where there is enough cumulative degree of disease, symptoms, signs, or laboratory abnormalities to motivate an intervention.

Source: Clinical endpoint (CC BY-SA 4.0 (Wikipedia)), retrieved 2026-10-26.