# Dalpiciclib or placebo plus fulvestrant in hormone receptor-positive and HER2-negative advanced breast cancer: a randomized, phase 3 trial

Source: https://onco.cc/key-papers/paper-dawna-1-nat-med-2021/  
OnCo record `paper-dawna-1-nat-med-2021` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Published report from the DAWNA-1 trial registered as NCT03927456, in Nature Medicine (2021), chosen as the most cited paper whose own text cites the registry id.

## Summary

Blockade of the cyclin-dependent kinase 4 and 6 pathway has been shown to be effective in the treatment of hormone receptor-positive advanced breast cancer (ABC). We report the interim results of DAWNA-1 ( NCT03927456), a double-blind, randomized, phase 3 trial of dalpiciclib (a new cyclin-dependent kinase 4 and 6 inhibitor) plus fulvestrant in hormone receptor-positive, HER2-negative ABC with disease progression after endocrine therapy. A total of 361 patients were randomized 2:1 to receive dalpiciclib plus fulvestrant or placebo plus fulvestrant. The study met the primary end point, showing significantly prolonged investigator-assessed progression-free survival with dalpiciclib plus fulvestrant versus placebo plus fulvestrant (median = 15.7, 95% confidence interval (CI) = 11.1-not reached versus 7.2, 95% CI = 5.6-9.2 months; hazard ratio = 0.42, 95% CI = 0.31-0.58; one-sided P < 0.0001 (boundary was P ≤ 0.008)). The most common grade 3 or 4 adverse events with dalpiciclib plus fulvestrant were neutropenia (84.2%) and leukopenia (62.1%). The incidence of serious adverse events was 5.8% with dalpiciclib plus fulvestrant versus 6.7% with placebo plus fulvestrant. Our findings support dalpiciclib plus fulvestrant as a new treatment option for pretreated hormone receptor-positive, HER2-negative ABC.

Indexed on Europe PMC as PubMed record 34737452 (DOI 10.1038/s41591-021-01562-9). Its abstract cites the registry id NCT03927456, which is how it was matched to this trial; no figure has been checked by an editor.

## Fields

- Kind: Key paper
- Last checked: 2026-09-22
- Tags: europepmc-ingest
- Journal: Nature Medicine
- Year: 2021
- DOI: 10.1038/s41591-021-01562-9
- Authors: Xu B, Zhang Q, Zhang P, et al.
- What it means: This is the paper Europe PMC returns for registry id NCT03927456 with the most citations, so it is the natural first reading for anyone following the DAWNA-1 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.

## Sources

- Nat Med 2021: https://doi.org/10.1038/s41591-021-01562-9
- PubMed: https://pubmed.ncbi.nlm.nih.gov/34737452/
- Europe PMC: https://europepmc.org/article/MED/34737452
- ClinicalTrials.gov NCT03927456: https://clinicaltrials.gov/study/NCT03927456

## Connected records

- trials: [DAWNA-1](https://onco.cc/trials/dawna-1/)
- journals: [Nature Medicine](https://onco.cc/journals/nature-medicine/)

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