ASCO 2025: Inavolisib-palbociclib-fulvestrant improves overall survival for advanced breast cancer
A Phase III trial has shown that combining inavolisib with palbociclib and fulvestrant significantly improves overall survival for patients with previously treated PIK3CA-mutated, HR-positive, HER2-negative advanced breast cancer.
Results from the INAVO120 trial presented at the 2025 ASCO Annual Meeting (May 30–June 3, IL, USA), support the use of an inavolisib-based regimen as a standard of care for PIK3CA-mutated, HR-positive, HER2-negative advanced breast cancer patients – a group with historically limited treatment options and a poor prognosis.
Earlier findings from the INAVO120 trial led to the US FDA’s approval of the combination in 2024, based on a more than doubled progression-free survival for HR+, HER2- PIK3CA-mutated metastatic breast cancer patients compared to current standard of care.
The newly presented data at ASCO 2025 now confirm a significant overall survival benefit. After a median follow up of just under 3 years, the median OS was 34 months for the inavolisib group vs. 27 months for the placebo group (comprising a placebo with palbociclib and fulvestrant).
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“The INAVO120 trial has identified a targeted treatment regimen that meaningfully improves survival in patients with untreated PIK3CA-mutated hormone receptor-positive metastatic breast cancer – a big step forward for these patients,” commented ASCO Expert in breast cancer, Jane Lowe Meisel (Winship Cancer Institute of Emory University School of Medicine, GA, USA).
Other key findings from the trial include that the inavolisib combination reduced the risk of death by 33% compared to the placebo group. Survival rates for patients on inavolisib were higher at time points evaluated post-treatment. Meanwhile, the objective response rate was 62.7% with inavolisib, compared to 28% with placebo. Additionally, the median time before needing chemotherapy was significantly longer: 35.6 months vs. 12.6 months.
“This study illustrates the importance of genomic testing at the time of diagnosis of hormone receptor-positive metastatic breast cancer, so that patients with PIK3CA mutations who qualify for this approach can be readily identified,” Lowe Meisel added.
Inavolisib is also being evaluated in the INAVO121, INAVO122 and INAVO123 Phase III trials, which focus on various treatment combinations for PIK3CA-mutated locally advanced or metastatic breast cancer.