Kazia Therapeutics Reports Positive Early Responses In Aggressive Breast Cancer Trial

Kazia Therapeutics Ltd. (NASDAQ:KZIA) on Tuesday shared a clinical update from its ongoing Phase 1b study evaluating paxalisib in combination with pembrolizumab and chemotherapy in patients with late-stage (Stage IV), metastatic triple-negative breast cancer (TNBC).

Merck & Co. Inc. (NYSE:MRK) sells pembrolizumab under the Keytruda brand name.

In December 2025, Kazia Therapeutics raised capital of approximately $46.5 million, and the company will use it to support the continued clinical development of its lead program, paxalisib.

To date, three patients with metastatic TNBC treated with paxalisib-based regimens have demonstrated meaningful clinical responses, including two partial responses (PRs) in trial participants and one confirmed complete metabolic response (CR) in a patient treated under an expanded access program.

Clinical Highlights

• 2 of 2 evaluable patients enrolled in the Phase 1b trial achieved partial responses.
• One advanced metastatic TNBC patient achieved a confirmed complete metabolic response following re-treatment with pembrolizumab/chemotherapy plus paxalisib (under an expanded access protocol).
• Responses observed in patients with visceral disease and multi-organ metastases.
• Median time on treatment to date is approximately 6.1 months, with all patients continuing on therapy at the time of this update.
• Paxalisib continues to demonstrate a generally favorable safety and tolerability profile when combined with pembrolizumab and chemotherapy at the 30 mg daily dose.

At the 30 mg daily dose, one case of Grade 1 hyperglycemia has been observed, requiring no intervention. Two serious adverse events (SAEs) have been reported to date, both deemed unrelated to paxalisib.

The company expects to activate two additional clinical sites by April 2026, with two further sites planned for mid-2026. Kazia continues to anticipate the targeted enrollment of twelve TNBC pts target by the end of 2026 and topline data readout in early 2027.

Kazia is also evaluating paxalisib in additional breast cancer populations, including earlier-stage TNBC and hormone receptor–positive, HER2-negative (HR+ / HER2-) breast cancer, where dysregulation of the PI3K/mTOR pathway is well established.

In July 2025, a 61-year-old woman patient with metastatic triple-negative breast cancer localized to the left upper lobe of the lung showed highly encouraging preliminary results at 21 days, with a >50% reduction in circulating tumor cells (CTCs) and a notable decrease in CTC clusters.

Price Action: KZIA stock surged to as high as $8.73 before slipping 10.21% to $7.120 at the last check on Tuesday, according to Benzinga Pro data.

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