Life sciences · Journal article
Nature Communications · October 21, 2026
No summary has been generated for this record yet. What follows is drawn from its source metadata only.
Journal article.
No findings were extractable from the material analysed.
Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.
The source did not state who this applies to in practice.
Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.
This record has not been graded across any dimension yet. Treat the label above as provisional and read the source.
What is missing. This record has no bottom line, key findings, reported figures, evidence dimensions. That is a gap in the analysis, not a judgement about the study.
Bireociclib plus fulvestrant improves outcomes in hormone receptor-positive, HER2-negative advanced breast cancer, but molecular determinants of benefit and resistance remain unclear. Here we report an exploratory longitudinal circulating tumor DNA (ctDNA) analysis of the randomized phase Ⅲ BRIGHT-2 trial (ClinicalTrials.gov, NCT05077449) in female patients, profiling 596 plasma samples collected at baseline, on treatment, and at end of treatment with a 1,021-gene panel. Detectable baseline ctDNA and higher molecular tumor burden are associated with shorter progression-free survival in both arms, consistent with greater disease burden and intrinsic risk. MYC, PI3K–AKT and gBRCA/HRR alterations define adverse genomic risk, whereas PIK3CA–ESR1 status shows an exploratory treatment-informative signal. Landmark analyses link on-treatment ctDNA clearance or molecular tumor burden reduction with favorable subsequent outcomes. End-of-treatment profiling identifies candidate resistance-associated alterations after bireociclib, including FGFR1, MDM2, and MYC amplifications and MAPK pathway activation. Longitudinal ctDNA profiling may refine risk stratification, response monitoring, and resistance tracking during CDK4/6 inhibitor-based therapy. This study shows that tracking tumor DNA in blood can help predict outcomes, monitor treatment response, and reveal resistance in women receiving bireociclib plus fulvestrant for hormone receptor-positive, HER2-negative advanced breast cancer.