PI3K inhibition in combination with tamoxifen in patients with metastatic HR+/HER2- breast cancer: clinical and circulating tumor DNA results - PubMed
3 months ago
- #PI3K inhibitor
- #breast cancer
- #ctDNA
- Study evaluates taselisib (PI3K inhibitor) combined with tamoxifen in metastatic HR+/HER2- breast cancer patients.
- POSEIDON trial: Phase II, randomized, placebo-controlled, conducted from 2016 to 2020.
- Primary endpoint: Progression-free survival (PFS) improvement with taselisib + tamoxifen vs. placebo + tamoxifen (4.8 vs. 3.2 months).
- Significant toxicity noted with taselisib, including diarrhea (40% any grade).
- Exploratory ctDNA analysis links high tumor fraction at baseline to worse PFS and OS.
- Conclusion: Efficacy shown but tolerability concerns limit clinical benefit; ctDNA may aid patient selection.