Kazia Therapeutics’ paxalisib monotherapy shows tumor cell cluster disruption

Kazia Therapeutics (KZIA) announced new findings from a collaborative research program led by Professor Sudha Rao at QIMR Berghofer. In this ex vivo study, blood samples from Stage IV HER2-positive metastatic breast cancer patients were profiled to evaluate the effect of paxalisib, Kazia’s investigational PI3K-mTOR inhibitor, on metastatic burden. Paxalisib monotherapy demonstrated a statistically significant reduction in single circulating tumor cells and achieved a complete – 100% – disruption of circulating tumor cell clusters containing three or more cells. Immunotherapy has demonstrated success across several solid tumors but has shown limited efficacy in HER2-positive breast cancer, underscoring the need for new therapeutic approaches. In this study, liquid biopsy profiling of Stage IV patients revealed that paxalisib treatment effectively disrupted CTCs and CTC clusters, which are considered biomarkers of aggressive disease and metastasis. Immunofluorescence analyses showed that paxalisib-treated blood samples from HER2-positive mBC patients achieved complete disruption of highly metastatic CTC clusters. Detailed datasets encompassing metastatic signatures and disrupted progenitor populations in Stage IV HER2-positive breast cancer have been submitted for presentation at an upcoming global oncology meeting in 2025.