Kazia Surges 80% on Preclinical Data Showing Paxalisib May Reverse Immunotherapy Resistance in Breast Cancer

Shares of Kazia Therapeutics (NASDAQ: KZIA) climbed 80% on Wednesday after the company announcednew preclinical data published in Molecular Cancer Therapeutics demonstrating that its lead asset, paxalisib, may overcome immunotherapy resistance in triple-negative breast cancer (TNBC), a notoriously aggressive and hard-to-treat subtype.

Conducted by Professor Sudha Rao at QIMR Berghofer Medical Research Institute, the study showed that paxalisib, a dual PI3K/mTOR inhibitor, reprogrammed the tumor microenvironment in TNBC models, increased T cell infiltration and activation, and significantly enhanced the anti-tumor effects of KEYTRUDA (pembrolizumab). The combination led to robust tumor regression and prolonged survival in preclinical models.

“This landmark study offers a mechanistic and translational foundation for our newly launched Phase 1b clinical trial of paxalisib in advanced breast cancer,” said Dr. John Friend, CEO of Kazia. “It not only extends the therapeutic potential of paxalisib beyond brain cancers but also positions it at the forefront of innovative immunotherapy combinations in solid tumors.”

Kazia recently initiated a Phase 1b trial of paxalisib in combination with immunotherapy and chemotherapy in patients with advanced breast cancer. The study builds on earlier data suggesting that dual inhibition of PI3K and mTOR is more effective than targeting PI3K alone, and that paxalisib may play a unique role in reversing immune suppression associated with resistant tumors.

Paxalisib is already being developed in multiple brain cancer indications, including glioblastoma and brain metastases. The new data opens a path toward potentially broadening its clinical utility in solid tumors, including breast cancer, where unmet need remains high.

According to analysts at Maxim Group, who maintain a Buy rating and 15 dollar price target on KZIA, the preclinical results further de-risk the ongoing TNBC trial and could act as an early inflection point for the stock. While glioblastoma remains Kazia’s lead indication, the breast cancer program offers additional upside and could accelerate visibility around the company’s broader platform. Preliminary clinical data from the TNBC study may be presented in the first half of 2026.

With a newly launched trial, promising mechanistic data, and interest in immunotherapy-enhancing strategies, investors are taking note of Kazia’s expanding footprint in oncology.