Sometimes in oncology, you get results that make everyone sit up and pay attention. Kazia Therapeutics (KZIA) had one of those moments Tuesday evening, sending shares soaring over 51% in after-hours trading after the Sydney-based biotech announced a patient with stage IV triple-negative breast cancer achieved what's called an immune-complete response.

A Rare Complete Response

Here's what happened: A patient being treated under an FDA-approved single-patient expanded access protocol received a combination of Kazia's experimental drug paxalisib along with pembrolizumab (better known as Keytruda) and standard chemotherapy. After roughly three months of treatment, a PET/CT scan revealed that all previously identified lesions had completely resolved metabolically, meeting the criteria for an initial immune-complete response under iRECIST standards.

To understand why this matters, you need to know that complete responses in stage IV metastatic triple-negative breast cancer are vanishingly rare. This is one of the most aggressive forms of breast cancer, and when it's already metastasized to stage IV, getting all tumors to disappear is not something doctors see often.

The company had previously reported that this same patient's tumor burden dropped 86% after just three weeks of treatment. Now, at the three-month mark, the response has deepened to complete metabolic resolution.

"Observing an initial complete response in a patient with metastatic triple-negative breast cancer is an extremely encouraging clinical finding," said John Friend, CEO of Kazia Therapeutics. "The depth of response aligns closely with our mechanistic hypothesis that paxalisib may meaningfully enhance anti-tumor immunity when combined with checkpoint blockade."

Upcoming Data Presentations

Kazia also announced that two presentations have been accepted at the 2025 San Antonio Breast Cancer Symposium, scheduled for December 10-14. The presentations will cover a Phase 1b study evaluating the safety, tolerability, and clinical activity of paxalisib combined with either olaparib or pembrolizumab/chemotherapy in advanced breast cancer patients, plus research on using liquid biopsy to track PI3K-mTOR residual disease signatures in metastatic breast cancer.

The Nasdaq Problem

The clinical news comes at a critical time for Kazia. Last week, the company received a staff determination letter from Nasdaq stating it hadn't met the $35 million minimum Market Value of Listed Securities requirement by the November 10 deadline. The company was originally notified of this deficiency back on May 12. Kazia plans to request a hearing before a Hearings Panel, which automatically pauses any suspension or delisting action until the panel reaches a decision.

Stock Movement

Kazia (KZIA) closed Tuesday's regular session at $5.76, down 5.29%, before the after-hours surge to $8.74. Year-to-date, the stock is still down 34.02%, though it's climbed 58.24% over the past six months. With a market capitalization of just $9.56 million, shares have traded in a wide range between $2.86 and $30.05 over the past year—reflecting both the volatility and risk inherent in small-cap biotech investing.