KZIA Kazia Therapeutics Ltd

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of June, 2025

Commission File Number 000-29962

Kazia Therapeutics Limited

(Translation of registrant’s name into English)

Three International Towers Level 24 300 Barangaroo Avenue Sydney NSW 2000

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒   Form 40-F  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ☐

INFORMATION CONTAINED IN THIS FORM 6-K REPORT

On June 5, 2025, Kazia Therapeutics Limited (the “Company”) issued a press release titled “Kazia Therapeutics Announces First Patient Dosed in Phase 1b Trial of Paxalisib in Advanced Breast Cancer”. A copy of this release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

The Company hereby incorporates by reference the information contained herein, including Exhibit 99.1, except for the quotes of Dr. John Friend, Chief Executive Officer of the Company, contained in Exhibit 99.1, into the Company’s registration statements on Form F-3 (File No. 333-276091 and 333-281937).

EXHIBIT LIST

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Exhibit 99.1

Kazia Therapeutics Announces First Patient Dosed in Phase 1b Trial of Paxalisib in Advanced Breast Cancer

Trial is expected to provide key insights on how paxalisib therapy can be combined with established immunotherapies and standard of care chemotherapy to improve patient outcomes in advanced breast cancer

Sydney, Australia – June 5, 2025. Kazia Therapeutics Limited (NASDAQ: KZIA) (“Kazia” or the “Company”), an oncology-focused biotechnology company developing innovative therapies for difficult-to-treat cancers, today announced that the first patient has been dosed in a Phase 1b clinical trial sponsored by Kazia. The study evaluates paxalisib, the Company’s dual PI3K/mTOR inhibitor, in combination with olaparib or pembrolizumab for patients with advanced breast cancer.

This multi-center, open-label, randomized trial is designed to assess the safety, tolerability, and preliminary efficacy of multiple paxalisib-based treatment combinations. The study also includes deep biomarker profiling to support future development and early signals of clinical activity.

“The start of patient dosing in this Kazia-sponsored study marks an important milestone in the evolution of paxalisib beyond brain cancer and into broader solid tumor applications,” said Dr. John Friend, Chief Executive Officer of Kazia. “By leveraging the dual inhibition of PI3K and mTOR, this trial builds on compelling preclinical data showing epigenetic modulation in aggressive breast cancer pre-clinical models. We believe the combinations explored here may provide a more effective therapeutic strategy by simultaneously targeting tumor metabolism, DNA repair, and immune evasion.”

About the Study

This Phase 1b trial (ACTRNXXX) will enroll patients with advanced breast cancer into two treatment arms:

Participants will be evaluated for:

Strategic Significance

“The integration of paxalisib into combination regimens reflects our strategy of building value through differentiated science and high-quality collaborations,” added Dr. Friend. “As this study progresses, we aim to share interim updates that may further underscore the potential of paxalisib to impact multiple indications with poor prognoses.”

For investor and media, please contact Alex Star, Managing Director LifeSci Advisors LLC

Astarr@lifesciadvisors.com, +1-201-786-8795.

About Kazia Therapeutics Limited

Kazia Therapeutics Limited (NASDAQ: KZIA) is an oncology-focused drug development company, based in Sydney, Australia. Our lead program is paxalisib, an investigational brain penetrant inhibitor of the PI3K / Akt / mTOR pathway, which is being developed to treat multiple forms of brain cancer. Licensed from Genentech in late 2016, paxalisib is or has been the subject of ten clinical trials in this disease. A completed Phase 2/3 study in glioblastoma (GBM-Agile) was reported in 2024 and discussions are ongoing for designing and executing a pivotal registrational study in pursuit of a standard approval. Other clinical trials involving paxalisib are ongoing in brain metastases, diffuse midline gliomas, and primary CNS lymphoma, with several of these trials having reported encouraging interim data. Paxalisib was granted Orphan Drug Designation for glioblastoma by the FDA in February 2018, and Fast Track Designation (FTD) for glioblastoma by the FDA in August 2020. Paxalisib was also granted FTD in July 2023 for the treatment of solid tumour brain metastases harboring PI3K pathway mutations in combination with radiation therapy. In addition, paxalisib was granted Rare Pediatric Disease Designation and Orphan Drug Designation by the FDA for diffuse intrinsic pontine glioma in August 2020, and for atypical teratoid / rhabdoid tumours in June 2022 and July 2022, respectively. Kazia is also developing EVT801, a small molecule inhibitor of VEGFR3, which was licensed from Evotec SE in April 2021. Preclinical data has shown EVT801 to be active against a broad range of tumour types and has provided evidence of synergy with immuno-oncology agents. A Phase I study has been completed and preliminary data was presented at 15th Biennial Ovarian Cancer Research Symposium in September 2024. For more information, please visit www.kaziatherapeutics.com or follow us on X @KaziaTx.

Forward-Looking Statements

This announcement may contain forward-looking statements, which can generally be identified as such by the use of words such as “may,” “will,” “estimate,” “future,” “forward,” “anticipate,” or other similar words. Any statement describing Kazia’s future plans, strategies, intentions, expectations, objectives, goals or prospects, and other statements that are not historical facts, are also forward looking statements, including, but not limited to, statements regarding: the timing for results and data related to Kazia’s clinical and preclinical trials, Kazia’s strategy and plans with respect to its programs, including paxalisib and EVT801, the potential results of its Phase 1b clinical trial evaluating paxalisib in combination with olaparib or pembrolizumab for patients with advanced breast cancer, the potential benefits of paxalisib as an investigational PI3K/mTOR inhibitor, timing for any regulatory submissions or discussions with regulatory agencies, the potential market opportunity for paxalisib and Kazia’s intent and efforts to regain and/or maintain compliance with the applicable Nasdaq continued listing requirements and standards. Such statements are based on Kazia’s current expectations and projections about future events and future trends affecting its business and are subject to certain risks and uncertainties that could cause actual results to differ materially from those anticipated in the forward-looking statements, including risks and uncertainties: associated with clinical and preclinical trials and product development, related to regulatory approvals, related to the impact of global economic conditions, and related to Kazia’s ability to regain and/or maintain compliance with the applicable Nasdaq continued listing requirements and standards. These and other risks and uncertainties are described more fully in Kazia’s Annual Report, filed on form 20-F with the SEC, and in subsequent filings with the United States Securities and Exchange Commission. Kazia undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events, or otherwise, except as required under applicable law. You should not place undue reliance on these forward-looking statements, which apply only as of the date of this announcement.

This announcement was authorized for release by Dr John Friend, CEO