{"entity":{"id":"molecular-response","kind":"term","name":"Molecular response (MMR, MR4, treatment-free remission)","aka":["major molecular response","MR4","MR4.5","deep molecular response","complete molecular response","BCR-ABL1 transcript","BCR::ABL1 IS","International Scale","treatment-free remission","TFR","molecular relapse","cytogenetic response","complete cytogenetic response","early molecular response","cytogenetic responses","molecular responses"],"tldr":"In chronic myeloid leukaemia, how far the leukaemia gene signal in the blood has fallen, measured in logs: a 1,000-fold drop is a major molecular response, a 10,000-fold drop (MR4) is 'deep'. Deep responses held for two years let some patients stop their pills.","summary":"Quantitative PCR for BCR::ABL1 transcripts on the International Scale defines milestones: ≤10% at 3 months (early molecular response), ≤1% (complete cytogenetic response equivalent), ≤0.1% (MMR) by 12 months, ≤0.01% (MR4) and ≤0.0032% (MR4.5). Missing milestones triggers a switch of TKI. Sustained deep response for at least two years permits a supervised stop; about half stay in treatment-free remission and the rest regain response on restarting (EURO-SKI). 'Molecular relapse' is a rising transcript before any clinical sign. The concept is being borrowed for ctDNA-guided stopping in solid tumours.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Chronic_myelogenous_leukemia","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Chronic_myelogenous_leukemia"}],"tags":[],"related":["philadelphia-chromosome","umrd","tki-term","fixed-duration"],"cancers":[],"sections":["targeted-therapy","diagnostics"],"technologies":[],"targets":[],"drugs":["imatinib","asciminib","nilotinib","dasatinib"],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Biomarkers"},"route":"/terms/molecular-response/","neighbours":{"term":[{"id":"abl1-kinase-domain-mutations","kind":"term","name":"BCR::ABL1 kinase domain mutations (T315I and others)","route":"/terms/abl1-kinase-domain-mutations/"},{"id":"fixed-duration","kind":"term","name":"Fixed-duration vs continuous therapy","route":"/terms/fixed-duration/"},{"id":"mpn-driver-mutations","kind":"term","name":"MPN driver mutations (JAK2 V617F, CALR, MPL) and allele burden","route":"/terms/mpn-driver-mutations/"},{"id":"philadelphia-chromosome","kind":"term","name":"Philadelphia chromosome (Ph+, BCR::ABL1)","route":"/terms/philadelphia-chromosome/"},{"id":"sokal-elts-scores","kind":"term","name":"Sokal and ELTS risk scores (chronic myeloid leukaemia)","route":"/terms/sokal-elts-scores/"},{"id":"tki-term","kind":"term","name":"Tyrosine kinase inhibitor (TKI)","route":"/terms/tki-term/"},{"id":"umrd","kind":"term","name":"Undetectable MRD (uMRD / MRD-negative)","route":"/terms/umrd/"}],"section":[{"id":"diagnostics","kind":"section","name":"Diagnostics & Biomarkers","route":"/fronts/diagnostics/"},{"id":"targeted-therapy","kind":"section","name":"Targeted Therapy","route":"/fronts/targeted-therapy/"}],"drug":[{"id":"asciminib","kind":"drug","name":"Asciminib","route":"/drugs/asciminib/"},{"id":"dasatinib","kind":"drug","name":"Dasatinib","route":"/drugs/dasatinib/"},{"id":"imatinib","kind":"drug","name":"Imatinib","route":"/drugs/imatinib/"},{"id":"nilotinib","kind":"drug","name":"Nilotinib","route":"/drugs/nilotinib/"}],"cancer":[{"id":"advanced-systemic-mastocytosis","kind":"cancer","name":"Advanced systemic mastocytosis (aggressive SM, SM with an associated haematological neoplasm, mast cell leukaemia)","route":"/cancers/advanced-systemic-mastocytosis/"},{"id":"cml-chronic-phase","kind":"cancer","name":"Chronic myeloid leukaemia, chronic phase","route":"/cancers/cml-chronic-phase/"},{"id":"indolent-systemic-mastocytosis","kind":"cancer","name":"Indolent and smouldering systemic mastocytosis","route":"/cancers/indolent-systemic-mastocytosis/"},{"id":"systemic-mastocytosis","kind":"cancer","name":"Systemic mastocytosis","route":"/cancers/systemic-mastocytosis/"}],"biomarker":[{"id":"bcr-abl1-transcript","kind":"biomarker","name":"BCR::ABL1 transcript (Philadelphia chromosome, quantitative PCR)","route":"/biomarkers/bcr-abl1-transcript/"},{"id":"npm1-mutation","kind":"biomarker","name":"NPM1 mutation","route":"/biomarkers/npm1-mutation/"}]}}