-Trial Combines LIXTE's LB-100 with Dostarlimab; Results Give Patients New Hope

for a Challenging Disease with Limited Therapeutic Options-

BOCA RATON, Fla., April 13, 2026 (GLOBE NEWSWIRE) -- LIXTE Biotechnology Holdings, Inc. ("LIXTE" or the "Company") (NASDAQ:LIXT), a clinical stage pharmaceutical and med-tech company focused on advancing cancer treatments, today announced the presentation of preliminary results for a clinical trial testing the combination of Lixte's proprietary compound LB100 in combination with Dostarlimab at the 2026 Conference of the Society of Gynecological Cancer, April 10-13, in San Juan, Puerto Rico.

The annual conference brings together a diverse group of specialists, including gynecologic oncologists, radiation oncologists, nurses, researchers and others to share the latest scientific advancements. It features exhibitors from various medical device and pharmaceutical companies, showcasing cutting-edge products and services tailored for the gynecologic cancer care team.

"The findings being presented provide new hope for patients with ovarian cancer, a disease that thus far has limited therapeutic options," said Bas van der Baan, LIXTE's Chief Scientific Officer. "LIXTE's proprietary compound, LB-100, combined with GSK's anti PD1 drug Dostarlimab, has shown an acceptable safety profile. All 21 planned participants in the trial have been enrolled, and 20 were evaluated for efficacy in this interim analysis. Based on those favorable results, an additional cohort of 21 patients with a higher exposure to LB-100 is in the process of enrolling."

Trial Results

At a median follow-up length of 12 months (range 1.4-22), median OS has not been reached. However, OS probability was 0.84 (95%CI 0.64-0.94) at 6 months and 0.69 (95% CI 0.44-0.84) at 12 months. The Disease Control Rate was 40% (8/20, 95% CI 19.1-63.9%).

The trial is based on the observation by the lead clinical investigator Amir Jazaeri MD, Professor of Gynecologic Oncology at The University of Texas MD Anderson Cancer Center, that a genetically acquired reduction in PP2A activity may increase responsiveness to immune checkpoint blockade (ICB) in Ovarian Clear Cell Carcinoma (OCCC), particularly in tumors harboring somatic PPP2R1A mutations resulting in loss of protein phosphatase 2A (PP2A) function.

"We are learning more about the molecular features of ovarian clear-cell carcinomas that correlate with benefit from immune checkpoint inhibitors," said Dr. Jazaeri. "This study investigates how to use immunotherapy combinations such as Dostarlimab and LB-100 to expand the benefit for patients whose tumors do not carry these features."

Specifically, prior investigation reported markedly prolonged overall survival (OS) with ICB in patients with PPP2R1A-mutant OCCC (66.9 months versus 9.2 months for patients with wild-type tumors). This suggested that reducing PP2A pharmacologically with LB-100 may enhance the anti-tumor effect of the PD-1 blocking monoclonal antibody, dostarlimab-gxly, in patients with Ovarian Clear Cell Carcinoma lacking the genetic reduction in PP2A.

About LIXTE Biotechnology Holdings, Inc.

LIXTE Biotechnology Holdings, Inc. is a clinical-stage pharmaceutical and med-tech company focused on new targets for cancer drug development and developing and commercializing cancer therapies. LIXTE has demonstrated that LB-100, its lead compound and first-in-class lead clinical PP2A inhibitor, is well-tolerated in cancer patients at doses associated with anti-cancer activity. Based on published preclinical data, LB-100 has the potential to significantly enhance chemotherapies and immunotherapies and improve outcomes for patients with cancer. It is part of a pioneering effort in an entirely new field of cancer biology – activation lethality – that is advancing a new treatment paradigm. LIXTE's novel approach is covered by a comprehensive patent portfolio, with proof-of-concept clinical trials currently in progress for Ovarian Clear Cell Carcinoma, Metastatic Colon Cancer and Advanced Soft Tissue Sarcoma. Additional information can be found at www.lixte.com.

Through LIXTE's wholly owned subsidiary, Liora Technologies Europe Ltd., the Company also is pioneering the development of electronically controlled proton therapy systems for treating tumors in various types of cancers. Liora's proprietary flagship technology, LiGHT System, is believed to provide significant advantages over currently available technologies for treating tumors with proton therapy. Additional information about Liora Technologies can be found at www.lioratechnologies.com.

Forward-Looking Statement Disclaimer

This announcement contains certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, and Section 21E of the Securities Exchange Act of 1934. For example, statements regarding the Company's financial position, business strategy and other plans and objectives for future operations, and assumptions and predictions about future activities, including the continuing development of proprietary compounds, the planning, funding, coordination and potential results of clinical trials, the patent and legal costs to protect and maintain the Company's intellectual property worldwide, are all forward-looking statements. These statements are generally accompanied by words such as "intend," anticipate," "believe," "estimate," "potential(ly)," "continue," "forecast," "predict," "plan," "may," "will," "could," "would," "should," "expect" or the negative of such terms or other comparable terminology.

The Company believes that the assumptions and expectations reflected in such forward-looking statements are reasonable, based on information available to it on the date hereof, but the Company cannot provide assurances that these assumptions and expectations will prove to have been correct or that the Company will take any action that the Company may presently be planning. However, these forward-looking statements are inherently subject to known and unknown risks and uncertainties. Actual results or experience may differ materially from those expected or anticipated in the forward-looking statements. Factors that could cause or contribute to such differences include, but are not limited to, regulatory policies, available cash resources, research results, competition from other similar businesses, and market and general economic factors.

Readers are urged to read the risk factors set forth in the Company's filings with the United States Securities and Exchange Commission at https://www.sec.gov. The Company disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

For more information about LIXTE, contact:

info@lixte.com

General Phone: (631) 830-7092; Investor Phone: (888) 289-5533

or

PondelWilkinson Inc. Investor Relations pwinvestor@pondel.com

Roger Pondel: (310) 279-5965; Laurie Berman: (310) 279-5962

Favorable Results of Ovarian Cancer Study Presented at Annual Society of Gynecological Care Conference