Background
Approximately 40% of hormone receptor positive/human epidermal receptor 2 negative (HR + /HER2-) metastatic breast cancer (mBC) patients harbor phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutations. However, associations between PIK3CA mutation status and clinical outcomes among patients with HR + /HER2- mBC have been heterogeneous across clinical trials. This meta-analysis was conducted to survey recently available trial data to assess the prognostic effects of PIK3CA among patients with HR + /HER2- mBC. METHODS: Randomized clinical trials reporting progression-free survival (PFS) or overall survival (OS) stratified by PIK3CA status in HR + /HER2- mBC were identified via systematic literature review. Trial arms receiving phosphatidylinositol 3-kinase (PI3K)-targeted therapies were excluded. Meta-regression analysis was used to estimate the association between PIK3CA status and PFS and OS among included studies.
Results
The analyzed data included 3,219 patients from 33 study arms across 11 trials (PIK3CA mutated: 1,386, wild type: 1,833). PIK3CA mutation was associated with shorter median PFS (difference [95% CI] (months): -1.8 [-3.4, -0.1], I2 = 35%) and shorter median OS (-8.4 [-13.4, -3.5], I2 = 58%, N = 1,545). Findings were similar for PFS rates at 6 months (odds ratio [95% CI]: 0.74 [0.59, 0.94], I2 = 42%, N = 3,160) and 12 months (0.76 [0.59, 0.99], I2 = 42%, N = 2,468) and directionally consistent but not statistically significant at 18 months (N = 1,726).
Conclusions
Pooling evidence across multiple studies, PIK3CA mutation was associated with shorter PFS and OS. These findings suggest a negative prognostic value of PIK3CA mutations in patients with HR + /HER2- mBC.
Associated People
Mirko Fillbrunn
Dr. Fillbrunn specializes in health economics and outcomes research (HEOR), biostatistics, and epidemiology. His expertise includes strategically developing and guiding the implementation of analytics throughout the entire product life cycle, including analyses of clinical trials and real-world health care data such as insurance claims, electronic health records, medical charts, and surveys. Dr. Fillbrunn’s contributions have informed clinical regulators and health care payers in both the US and global markets. His research has been published in several peer-reviewed journals and presented at clinical and health economic conferences. Prior to joining Analysis Group, Dr. Fillbrunn was a postdoctoral fellow at Harvard Medical School and Massachusetts General Hospital.