{"entity":{"id":"penelope-b","kind":"trial","name":"PENELOPE-B","aka":[],"tldr":"PENELOPE-B tested whether a year of the CDK4/6 inhibitor palbociclib after chemotherapy and surgery would prevent recurrence in women at high risk; it did not, one of two trials to show that palbociclib does not work in early breast cancer even though later drugs in the class do.","summary":"PENELOPE-B randomised 1250 women with hormone receptor-positive, HER2-negative breast cancer who still had invasive disease at surgery after neoadjuvant chemotherapy, and a high clinical-pathological risk score, to 13 cycles of palbociclib or placebo alongside standard endocrine therapy. The primary endpoint was invasive disease-free survival.\n\nPalbociclib did not improve invasive disease-free survival; an early separation of the curves disappeared with longer follow-up. Together with PALLAS, which tested two years of palbociclib in a broader population, it showed that palbociclib has no role in early breast cancer, while abemaciclib (monarchE) and ribociclib (NATALEE) proved effective, a reminder that the class does not behave as one drug.","status":"negative","asOf":"2026-09-17","links":[{"label":"ClinicalTrials.gov NCT01864746","url":"https://clinicaltrials.gov/study/NCT01864746"}],"tags":["subtype-trials"],"related":[],"cancers":["hr-positive-early-high-risk","breast-hr-positive","breast-cancer"],"sections":[],"technologies":["cdk46-inhibitor"],"targets":[],"drugs":["palbociclib"],"companies":["pfizer"],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":["sibylle-loibl"],"bottlenecks":[],"keyPapers":["paper-penelope-b-j-clin-oncol-2021"],"journals":[],"dependsOn":[],"notes":[],"nct":"NCT01864746","phase":"3","setting":"Hormone receptor-positive, HER2-negative early breast cancer with residual disease and high risk of relapse after neoadjuvant chemotherapy: one year of palbociclib or placebo added to endocrine therapy","sponsor":"German Breast Group (GBG Forschungs GmbH)","result":"One year of palbociclib added to endocrine therapy did not improve invasive disease-free survival.","started":"2013-10-30","startedType":"actual","yearReported":2021,"enrolled":1250,"enrolledBasis":"registry","outcomes":[{"endpoint":"Invasive disease-free survival","primary":true,"arms":[{"name":"Palbociclib + endocrine therapy","note":"Stratified hazard ratio with 95% repeated CI; 1250 randomised; 308 events; median follow-up 42.8 months"},{"name":"Placebo + endocrine therapy"}],"hr":0.93,"ci":[0.74,1.17],"p":"0.525","source":"https://doi.org/10.1200/jco.20.03639"}]},"route":"/trials/penelope-b/","neighbours":{"cancer":[{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","route":"/cancers/breast-cancer/"},{"id":"hr-positive-early-high-risk","kind":"cancer","name":"High-risk early HR-positive breast cancer","route":"/cancers/hr-positive-early-high-risk/"},{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"}],"technology":[{"id":"cdk46-inhibitor","kind":"technology","name":"CDK4/6 inhibitors","route":"/technologies/cdk46-inhibitor/"}],"drug":[{"id":"palbociclib","kind":"drug","name":"Palbociclib","route":"/drugs/palbociclib/"}],"company":[{"id":"pfizer","kind":"company","name":"Pfizer (incl. Seagen)","route":"/companies/pfizer/"}],"person":[{"id":"sibylle-loibl","kind":"person","name":"Sibylle Loibl","route":"/people/sibylle-loibl/"}],"paper":[{"id":"paper-penelope-b-j-clin-oncol-2021","kind":"paper","name":"Palbociclib for Residual High-Risk Invasive HR-Positive and HER2-Negative Early Breast Cancer-The Penelope-B Trial","route":"/key-papers/paper-penelope-b-j-clin-oncol-2021/"}]}}