Designation supports accelerated development of a Polθ inhibitor-PARP inhibitor combination for germline BRCA-mutated, HER2-negative breast cancer

HANGZHOU, China, October 14, 2026 – SynRx Therapeutics ("SynRx") today announced that earlier this month, the U.S. Food and Drug Administration (FDA) granted Fast Track designation to SYN818, SynRx's internally discovered Polθ (DNA polymerase theta) helicase domain inhibitor, in combination with olaparib. The designation is for the treatment of adult patients with germline BRCA-mutated (gBRCAm), HER2-negative locally advanced or metastatic breast cancer who have not previously received a PARP inhibitor. It is the first Polθ helicase domain inhibitor combination regimen to receive FDA Fast Track designation for this indication.

Addressing a clear unmet need

gBRCA-mutated, HER2-negative breast cancer is often aggressive and carries a high risk of recurrence. People who carry a BRCA mutation face a substantially higher lifetime risk of breast cancer than the general population and tend to present at a younger age, with more advanced stage and a poorer prognosis. PARP inhibitors are an important option in this setting, yet resistance after PARP inhibitor monotherapy remains a major clinical challenge for many patients.

SYN818 plus olaparib was designed for that gap. By pairing Polθ inhibition with PARP inhibition, SynRx aims to impose dual blockade on DNA damage repair pathways and open a new treatment path for patients with gBRCA-mutated, HER2-negative breast cancer. The combination is being studied clinically (NCT07156253).

"Fast Track designation for SYN818 with olaparib recognizes both the urgency of this disease setting and the logic of hitting two nodes in the DNA damage repair network," said Song Liu, Ph.D., CEO of SynRx Therapeutics. "We intend to work closely with the FDA to advance this program for patients who still need better options."

What Fast Track designation provides

FDA Fast Track designation is meant to facilitate development and expedite review of investigational therapies for serious conditions that have the potential to address an unmet medical need, with the goal of bringing important new medicines to patients earlier. Sponsors with Fast Track designation may receive:

· More frequent meetings and written communication with the FDA on development and trial design;

· Eligibility for accelerated approval and priority review, where applicable criteria are met; and

· The option to submit portions of a New Drug Application (NDA) on a rolling basis, rather than waiting to file a complete application before review can begin.

For SYN818 in combination with olaparib, the designation is expected to help SynRx move clinical development and regulatory interactions forward more efficiently. It does not mean the product is FDA approved.

About SYN818

SYN818 is a selective small-molecule inhibitor of Polθ helicase domain developed by SynRx. In tumors with impaired homologous recombination, including BRCA-mutated cancers, Polθ can serve as an important backup DNA repair route. Combining SYN818 with olaparib is intended to deepen DDR blockade through synthetic lethality, strengthen anti-tumor activity, and better address resistance that can follow PARP inhibitor monotherapy. SYN818 is investigational and has not been approved for commercial use by any regulatory authority.

About SynRx Therapeutics

SynRx Therapeutics is an innovative biotechnology company focused on DNA damage repair (DDR). Headquartered in Hangzhou, Zhejiang Province, China, SynRx has established drug discovery platforms, clinical research capabilities, and affiliates in China and overseas. Built on a synthetic lethality strategy, the company is advancing an original pipeline of oncology candidates, including small-molecule DDR inhibitors and other modalities, guided by its mission: "Targeting DNA damage repair to develop original anti-tumor innovative medicines."

Disclaimer

This press release is for public information on SynRx's R&D progress only. It is not advertising and does not constitute a recommendation or promotion of any drug or indication. Forward-looking statements about development plans, regulatory process, or potential clinical benefit involve risks and uncertainties; actual results may differ.

Contact

SynRx Therapeutics

Email: medical@synrx.cn

Tel: +86 0571-86360796

Expanded Access Policy Statement

SynRx Therapeutics ("SynRx") develops investigational medicines that target DNA damage repair for patients with cancer.

Investigational products have not been approved by the FDA or other regulators for commercial use, and regulators have not concluded that they are safe and effective for a specific use. SynRx evaluates its candidates in controlled clinical trials. Whenever feasible, patients should access SynRx investigational products by enrolling in a SynRx-sponsored trial. Trial listings are available at www.clinicaltrials.gov (search "SynRx Therapeutics"); questions may also be sent to medical@synrx.cn.

Expanded access (also called compassionate use) is a pathway that may allow a patient with a serious or immediately life-threatening condition to receive an investigational product outside a trial when no satisfactory alternative is available and trial participation is not possible.

Current policy. SynRx does not currently operate an expanded access program for its investigational products, including SYN818. Use is limited to clinical trials. SynRx will update this statement if that position changes.

How to inquire

Licensed treating physicians with questions about SynRx trials or this policy may contact:

SynRx Therapeutics – Medical Affairs

Email: medical@synrx.cn

Tel: +86 0571-86360796

Please submit inquiries from a licensed physician and include enough clinical detail for SynRx to understand the request (diagnosis and relevant history, prior therapies, why a trial is not feasible, and the product of interest). Patients should discuss options with their treating physician.

Acknowledgement timeline

SynRx aims to acknowledge complete physician inquiries related to this policy within about ten (10) business days. Because SynRx does not currently offer expanded access, the reply will generally confirm that expanded access is unavailable and, where helpful, point to open trial information.

General criteria if SynRx later considers expanded access

If SynRx later decides to consider expanded access for any candidate, requests would be reviewed case by case. Factors would typically include whether:

· the patient has a serious or immediately life-threatening condition and lacks a comparable or satisfactory alternative;

· enrollment in a SynRx trial is not possible (for example, ineligibility, no open study, or practical barriers that make participation not feasible);

· available data suggest the potential benefit could justify the potential risks for that patient;

· providing the product would not disrupt ongoing trials or the broader development program, including supply; and

· required regulatory, IRB/ethics, and informed-consent steps can be completed.

Publishing this policy does not guarantee that any patient will receive an investigational product. SynRx may revise this policy at any time. This statement is intended to support compliance with section 561A of the Federal Food, Drug, and Cosmetic Act and related FDA guidance on making an expanded access policy publicly available.

Last updated: October 2026