{"entity":{"id":"control-arm","kind":"term","name":"Control arm and comparator (investigator's choice)","aka":["control arm","control group","comparator","comparator arm","active comparator","active control","standard arm","standard-of-care arm","investigator's choice","investigator choice","physician's choice","treatment of physician's choice","TPC","chemotherapy of choice","versus chemotherapy","vs chemotherapy","experimental arm","treatment arm","head-to-head","head to head","control arms","comparators"],"tldr":"The group in a randomised trial that gets the existing standard treatment, against which the new drug is judged. Whether the control is the true current standard, an outdated one, or a menu of options chosen by each doctor ('investigator's choice') changes how much a positive result means.","summary":"The comparator should be the best available treatment at the time; trials using a weaker control (chemotherapy alone when chemo-immunotherapy was standard, or a suboptimal dose) draw regulatory and ODAC criticism and may not translate into practice. Investigator's or physician's choice from a list of chemotherapies is common in later-line trials (ASCENT, DESTINY-Breast04, TROPiCS-02) and is realistic but heterogeneous. Head-to-head trials of two new agents are rare and mostly sponsored by challengers (MARIPOSA vs osimertinib, HARMONi-2 ivonescimab vs pembrolizumab). Placebo or observation controls are used where no active standard exists, as in adjuvant and maintenance settings.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Scientific_control","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Scientific_control"}],"tags":[],"related":["standard-of-care","double-blind","backbone-add-on","non-inferiority","trial-failure-modes","external-control-arm","clinical-equipoise","pragmatic-trial"],"cancers":[],"sections":["drug-discovery"],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":["destiny-breast04","keynote-024-189","act-iv","convert"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Trials"},"route":"/terms/control-arm/","neighbours":{"term":[{"id":"backbone-add-on","kind":"term","name":"Backbone, add-on and monotherapy","route":"/terms/backbone-add-on/"},{"id":"double-blind","kind":"term","name":"Blinding (double-blind, open-label, placebo-controlled)","route":"/terms/double-blind/"},{"id":"clinical-equipoise","kind":"term","name":"Clinical equipoise","route":"/terms/clinical-equipoise/"},{"id":"crossover","kind":"term","name":"Crossover in trials","route":"/terms/crossover/"},{"id":"declaration-of-helsinki","kind":"term","name":"Declaration of Helsinki","route":"/terms/declaration-of-helsinki/"},{"id":"external-control-arm","kind":"term","name":"External and synthetic control arms","route":"/terms/external-control-arm/"},{"id":"intention-to-treat","kind":"term","name":"Intention-to-treat (ITT) and per-protocol analysis","route":"/terms/intention-to-treat/"},{"id":"non-inferiority","kind":"term","name":"Non-inferiority trial","route":"/terms/non-inferiority/"},{"id":"pragmatic-trial","kind":"term","name":"Pragmatic trial","route":"/terms/pragmatic-trial/"},{"id":"standard-of-care","kind":"term","name":"Standard of care","route":"/terms/standard-of-care/"},{"id":"trial-failure-modes","kind":"term","name":"Why trials fail: underpowered, wrong endpoint, control arm drift, subgroup fishing, crossover","route":"/terms/trial-failure-modes/"}],"section":[{"id":"drug-discovery","kind":"section","name":"Drug Discovery Platforms","route":"/fronts/drug-discovery/"}],"trial":[{"id":"act-iv","kind":"trial","name":"ACT IV","route":"/trials/act-iv/"},{"id":"convert","kind":"trial","name":"CONVERT","route":"/trials/convert/"},{"id":"destiny-breast04","kind":"trial","name":"DESTINY-Breast04","route":"/trials/destiny-breast04/"},{"id":"keynote-024-189","kind":"trial","name":"KEYNOTE-024 & KEYNOTE-189","route":"/trials/keynote-024-189/"}]}}