Kazia Therapeutics Targets Immunotherapy-Resistant Colorectal Cancer

The findings, released September 1, demonstrate that paxalisib functions by altering the tumor microenvironment to improve immune visibility. When combined with pembrolizumab, the therapy achieved an additional 50% reduction in tumor volume compared to immunotherapy alone. Dr. Sudha Rao, Chief Scientific Officer at Kazia, noted that the drug appears to shift tumors from a resistant state to a responsive one, a mechanism that has not been successfully tapped by other PI3K/mTOR inhibitors in this specific cancer setting.

Approximately 85–90% of metastatic colorectal cancer cases are classified as microsatellite stable (MSS/pMMR), a group that typically shows little to no response to current checkpoint inhibitor therapies. To address this, Kazia is launching a five-arm Phase 2 clinical trial scheduled for early 2027. The study will evaluate paxalisib at varying dosages, both as a monotherapy and in combination with pembrolizumab, against the current standard of care. The company has also secured new patent filings to protect the intellectual property surrounding this application, while simultaneously building a biomarker program to identify which patients are most likely to benefit from the treatment.