# Alpelisib plus fulvestrant for PIK3CA-mutated, hormone receptor-positive, human epidermal growth factor receptor-2-negative advanced breast cancer: final overall survival results from SOLAR-1

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

## TL;DR

Later report from the SOLAR-1 trial registered as NCT02437318, in Annals of Oncology (2021); its title describes an updated or longer-term analysis.

## Summary

Background: Activation of the phosphatidylinositol-3-kinase (PI3K) pathway via PIK3CA mutations occurs in 28%-46% of hormone receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2-) advanced breast cancers (ABCs) and is associated with poor prognosis. The SOLAR-1 trial showed that the addition of alpelisib to fulvestrant treatment provided statistically significant and clinically meaningful progression-free survival (PFS) benefit in PIK3CA-mutated, HR+, HER2- ABC.

Patients and methods: Men and postmenopausal women with HR+, HER2- ABC whose disease progressed on or after aromatase inhibitor (AI) were randomized 1: 1 to receive alpelisib (300 mg/day) plus fulvestrant (500 mg every 28 days and once on day 15) or placebo plus fulvestrant. Overall survival (OS) in the PIK3CA-mutant cohort was evaluated by Kaplan-Meier methodology and a one-sided stratified log-rank test was carried out with an O'Brien-Fleming efficacy boundary of P ≤ 0.0161.

Results: In the PIK3CA-mutated cohort (n = 341), median OS [95% confidence interval (CI)] was 39.3 months (34.1-44.9) for alpelisib-fulvestrant and 31.4 months (26.8-41.3) for placebo-fulvestrant [hazard ratio (HR) = 0.86 (95% CI, 0.64-1.15; P = 0.15)]. OS results did not cross the prespecified efficacy boundary. Median OS (95% CI) in patients with lung and/or liver metastases was 37.2 months (28.7-43.6) and 22.8 months (19.0-26.8) in the alpelisib-fulvestrant and placebo-fulvestrant arms, respectively [HR = 0.68 (0.46-1.00)]. Median times to chemotherapy (95% CI) for the alpelisib-fulvestrant and placebo-fulvestrant arms were 23.3 months (15.2-28.4) and 14.8 months (10.5-22.6), respectively [HR = 0.72 (0.54-0.95)]. No new safety signals were observed with longer follow-up.

Conclusions: Although the analysis did not cross the prespecified boundary for statistical significance, there was a 7.9-month numeric improvement in median OS when alpelisib was added to fulvestrant treatment of patients with PIK3CA-mutated, HR+, HER2- ABC. Overall, these results further support the statistically significant prolongation of PFS observed with alpelisib plus fulvestrant in this population, which has a poor prognosis due to a PIK3CA mutation. CLINICALTRIALS.

Gov id: NCT02437318.

Indexed on Europe PMC as PubMed record 33246021 (DOI 10.1016/j.annonc.2020.11.011). Its abstract cites the registry id NCT02437318, 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: Annals of Oncology
- Year: 2021
- DOI: 10.1016/j.annonc.2020.11.011
- Authors: André F, Ciruelos EM, Juric D, et al.
- What it means: A second publication from the SOLAR-1 trial, later than the first and described in its title as an update or longer-term analysis. Read it with the primary publication linked from the trial page; 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.; Chosen as a later report by words in its title (updated, long-term, final, overall survival or a year count), not by reading the paper.

## Sources

- Ann Oncol 2021: https://doi.org/10.1016/j.annonc.2020.11.011
- PubMed: https://pubmed.ncbi.nlm.nih.gov/33246021/
- Europe PMC: https://europepmc.org/article/MED/33246021
- ClinicalTrials.gov NCT02437318: https://clinicaltrials.gov/study/NCT02437318

## Connected records

- trials: [SOLAR-1](https://onco.cc/trials/solar-1/)
- journals: [Annals of Oncology](https://onco.cc/journals/annals-of-oncology/)

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