{"entity":{"id":"paper-paloma-2-n-engl-j-med-2016","kind":"paper","name":"Palbociclib and Letrozole in Advanced Breast Cancer","aka":[],"tldr":"Published report from the PALOMA-2 trial registered as NCT01740427, in New England Journal of Medicine (2016), chosen as the most cited paper whose own text cites the registry id.","summary":"Background: A phase 2 study showed that progression-free survival was longer with palbociclib plus letrozole than with letrozole alone in the initial treatment of postmenopausal women with estrogen-receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. We performed a phase 3 study that was designed to confirm and expand the efficacy and safety data for palbociclib plus letrozole for this indication.\n\nMethods: In this double-blind study, we randomly assigned, in a 2:1 ratio, 666 postmenopausal women with ER-positive, HER2-negative breast cancer, who had not had prior treatment for advanced disease, to receive palbociclib plus letrozole or placebo plus letrozole. The primary end point was progression-free survival, as assessed by the investigators; secondary end points were overall survival, objective response, clinical benefit response, patient-reported outcomes, pharmacokinetic effects, and safety.\n\nResults: The median progression-free survival was 24.8 months (95% confidence interval [CI], 22.1 to not estimable) in the palbociclib-letrozole group, as compared with 14.5 months (95% CI, 12.9 to 17.1) in the placebo-letrozole group (hazard ratio for disease progression or death, 0.58; 95% CI, 0.46 to 0.72; P<0.001). The most common grade 3 or 4 adverse events were neutropenia (occurring in 66.4% of the patients in the palbociclib-letrozole group vs. 1.4% in the placebo-letrozole group), leukopenia (24.8% vs. 0%), anemia (5.4% vs. 1.8%), and fatigue (1.8% vs. 0.5%). Febrile neutropenia was reported in 1.8% of patients in the palbociclib-letrozole group and in none of the patients in the placebo-letrozole group. Permanent discontinuation of any study treatment as a result of adverse events occurred in 43 patients (9.7%) in the palbociclib-letrozole group and in 13 patients (5.9%) in the placebo-letrozole group.\n\nConclusions: Among patients with previously untreated ER-positive, HER2-negative advanced breast cancer, palbociclib combined with letrozole resulted in significantly longer progression-free survival than that with letrozole alone, although the rates of myelotoxic effects were higher with palbociclib-letrozole. (Funded by Pfizer; PALOMA-2 ClinicalTrials.gov number, NCT01740427.).\n\nIndexed on Europe PMC as PubMed record 27959613 (DOI 10.1056/nejmoa1607303). Its abstract cites the registry id NCT01740427, which is how it was matched to this trial; no figure has been checked by an editor.","asOf":"2026-09-22","links":[{"label":"N Engl J Med 2016","url":"https://doi.org/10.1056/nejmoa1607303"},{"label":"PubMed","url":"https://pubmed.ncbi.nlm.nih.gov/27959613/"},{"label":"Europe PMC","url":"https://europepmc.org/article/MED/27959613"},{"label":"ClinicalTrials.gov NCT01740427","url":"https://clinicaltrials.gov/study/NCT01740427"}],"tags":["europepmc-ingest"],"related":[],"cancers":[],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":["paloma-2"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":["nejm"],"dependsOn":[],"notes":[],"journal":"New England Journal of Medicine","year":2016,"doi":"10.1056/nejmoa1607303","pmid":"27959613","authors":"Finn RS, Martin M, Rugo HS, et al.","paperType":"rct","findings":[],"whatItMeans":"This is the paper Europe PMC returns for registry id NCT01740427 with the most citations, so it is the natural first reading for anyone following the PALOMA-2 trial. Read the abstract above alongside the trial page and the registry entry; the record was linked automatically and its figures have not been checked by hand.","caveats":["Matched to the trial by the registry id cited in the Europe PMC record; the summary reproduces the record's abstract and no figure has been verified against the full paper."]},"route":"/key-papers/paper-paloma-2-n-engl-j-med-2016/","neighbours":{"trial":[{"id":"paloma-2","kind":"trial","name":"PALOMA-2","route":"/trials/paloma-2/"}],"journal":[{"id":"nejm","kind":"journal","name":"New England Journal of Medicine","route":"/journals/nejm/"}],"idea":[{"id":"idea-cdk4-selective-first-line","kind":"idea","name":"CDK4-selective inhibitors as the new first-line backbone","route":"/ideas/idea-cdk4-selective-first-line/"}]}}