Drug Combo Breakthrough: Paxalisib, Pembrolizumab, and Chemo Show Promise in Breast Cancer Clinical Trial

Early results from a Phase 1b trial show a drug combo significantly reduces circulating tumor cells in metastatic triple-negative breast cancer, offering new hope.

Drug Combo Breakthrough: Paxalisib, Pembrolizumab, and Chemo Show Promise in Breast Cancer Clinical Trial

The landscape of breast cancer treatment is constantly evolving, and recent news from a Phase 1b clinical trial is generating excitement. This trial explores a novel drug combination—Paxalisib, pembrolizumab (Keytruda®), and standard chemotherapy—for metastatic triple-negative breast cancer.

Early Optimism: A Glimpse of Hope

Kazia Therapeutics announced encouraging preliminary results from the first patient in their Phase 1b trial. The 61-year-old woman with metastatic triple-negative breast cancer experienced a greater than 50% reduction in circulating tumor cells (CTCs) and a notable decrease in CTC clusters after just one cycle (21 days) of the investigational regimen.

Why This Matters: Targeting Metastasis

CTC clusters are known to be significant drivers of metastasis, resisting apoptosis, evading immune detection, and efficiently seeding new tumor sites. Standard chemotherapy can sometimes transiently increase CTCs, while immunotherapy alone may have delayed or modest effects. The rapid reduction in both CTC numbers and clusters with this drug combo is a potentially significant improvement.

The Science Behind the Success

These early clinical data mirror preclinical findings published in Molecular Cancer Therapeutics, highlighting Paxalisib's ability to disrupt both single CTCs and multicellular clusters when combined with immunotherapy. This reflects a synergistic effect, potentially offering a more effective early intervention against systemic disease progression.

Looking Ahead: What's Next for the Clinical Trial?

Kazia Therapeutics is moving forward with several key steps:

• Exploring the relationship between CTC kinetics and radiographic responses.
• Continuing enrollment in the Phase 1b study to assess safety, tolerability, and pharmacodynamics.
• Conducting a comprehensive analysis of the immune microenvironment and CTC kinetics across all patients.
• Monitoring long-term outcomes, including imaging, progression-free survival, and correlation with molecular biomarkers.

A New York State of Mind: Cautious Optimism

While it's only one patient, the early results are undeniably exciting. Dr. John Friend, CEO of Kazia Therapeutics, expressed strong optimism, emphasizing the potential of this combination to offer a meaningful early intervention against systemic disease progression. Of course, more data is needed to confirm these initial findings and determine the long-term efficacy and safety of this drug combo. But for now, it's a reason to feel a little bit brighter about the future of breast cancer treatment.