Kazia Therapeutics Highlights New Clinical and Translational Findings Demonstrating Paxalisib's Ability to Reinvigorate Anti-Tumor Immunity Across Multiple Advanced Breast Cancer Populations including TNBC and HER2+

Core Insights - Kazia Therapeutics announced promising data from the 2025 San Antonio Breast Cancer Symposium, highlighting the efficacy of paxalisib in treating HER2-positive metastatic breast cancer and triple-negative breast cancer (TNBC) [1][2]. Group 1: Clinical Findings - The first patient in the TNBC Phase 1b trial showed a 76% reduction in tumor volume and significant decreases in circulating tumor cells (CTC) and clusters [1]. - Paxalisib demonstrated a 42% reduction in single CTCs and a 78% reduction in CTC clusters, including large clusters associated with metastatic progression [6]. - Early biomarker data indicated that paxalisib has measurable biological activity after just one treatment cycle [5]. Group 2: Mechanistic Insights - Paxalisib disrupts aggressive CTC clusters and reverses resistance pathways, enhancing immune response by revitalizing exhausted T- and B-cell populations [2][8]. - The drug targets mesenchymal, metastatic, and epigenetically resistant CTC clusters, which are key drivers of metastasis [11]. - There is evidence of epigenetic reprogramming of CTCs towards less aggressive phenotypes, confirmed through digital pathology [7]. Group 3: Broader Implications - The findings suggest that paxalisib's effects are relevant across multiple breast cancer subtypes, not just TNBC, indicating a potential for broader therapeutic applications [9]. - Kazia's research points to a unifying biology across breast cancer subtypes, suggesting that paxalisib could address unmet needs in current treatment paradigms [9]. - The company is exploring combination therapies with pembrolizumab and PARP inhibitors, which may enhance treatment efficacy in various breast cancer contexts [12].