{"entity":{"id":"backbone-add-on","kind":"term","name":"Backbone, add-on and monotherapy","aka":["backbone","chemotherapy backbone","backbone therapy","add-on","add-on therapy","monotherapy","single agent","single-agent","single-agent activity","combination partner","chemotherapy backbones","single agents"],"tldr":"Trial-design vocabulary: the backbone is the established treatment everyone in the trial receives; the add-on is the new drug tested on top of it; monotherapy means the drug alone. Most modern approvals are add-ons to a backbone.","summary":"Testing a new drug added to standard therapy (backbone) versus the backbone alone is the fastest route to approval because it needs no head-to-head against the standard, but it means patients receive more drugs and more toxicity, and it can obscure whether the new agent could replace rather than supplement (the 'chemotherapy-free' question in CLL, lung cancer and myeloma). Single-agent activity in early trials (objective response rate as monotherapy) is the usual evidence that a drug contributes. Regulators sometimes require 'contribution of components' studies when a combination is approved without it.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Combination_therapy","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Combination_therapy"}],"tags":[],"related":["doublet-triplet","control-arm","orr","de-escalation"],"cancers":[],"sections":["chemotherapy"],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Treatment jargon"},"route":"/terms/backbone-add-on/","neighbours":{"term":[{"id":"control-arm","kind":"term","name":"Control arm and comparator (investigator's choice)","route":"/terms/control-arm/"},{"id":"de-escalation","kind":"term","name":"De-escalation, escalation and response-adapted therapy","route":"/terms/de-escalation/"},{"id":"doublet-triplet","kind":"term","name":"Doublet, triplet and quadruplet regimens","route":"/terms/doublet-triplet/"},{"id":"orr","kind":"term","name":"Objective response rate (ORR)","route":"/terms/orr/"}],"section":[{"id":"chemotherapy","kind":"section","name":"Chemotherapy","route":"/fronts/chemotherapy/"}]}}