HOUSTON (September 9, 2025) – Salarius Pharmaceuticals, Inc. (Nasdaq: SLRX) (Salarius or the Company) announces that on September 4, 2025 the Company received notification from The Nasdaq Stock Market LLC (Nasdaq) that it has regained compliance with Listing Rule 5550(a)(2), the Minimum Bid Price Requirement.

By meeting the Minimum Bid Price Requirement, Salarius has achieved one of the milestones in regaining compliance with all Nasdaq continued listing standards. As previously disclosed on August 27, 2025, Salarius has until October 20, 2025 to regain compliance with Nasdaq Listing Rule 5550(b)(1), the Equity Standard Requirement.

Nasdaq further notified the Company that it will be subject to a Mandatory Panel Monitor for a period of one year from September 4, 2025. If, within that one-year monitoring period, the Listing Qualifications Staff finds the Company out of compliance with the Minimum Bid Price Requirement that was the subject of the exception, the Staff will issue a delisting determination letter and the Company will have the opportunity to request a hearing with the Nasdaq Hearings Panel.

On January 13, 2025, Salarius announced it had entered into a definitive merger agreement for a business combination with Decoy Therapeutics, Inc. (Decoy), a privately held preclinical biopharmaceutical company engineering the next generation of peptide conjugate therapeutics. Under the agreement, Decoy will merge with a wholly owned subsidiary of Salarius, subject to the closing conditions set forth in the agreement. The newly formed company will be named Decoy Therapeutics.

The proposed transaction, if consummated, is expected to facilitate multiple value-creating inflection points with Decoy’s pipeline of peptide conjugate therapeutics engineered by its IMP3ACT platform, which allows for the rapid computational design and manufacturing of innovative peptide conjugate therapeutics. Decoy’s product pipeline targets unmet needs in respiratory infectious diseases and gastroenterology (GI) oncology indications. In addition to advancing the development of Decoy’s IMP3ACT platform, the combined company intends to incorporate Salarius’ oral small molecule protein degrader SP-3164 into a highly targeted peptide-based proteolysis targeting chimeras (PROTACS) drug candidate.

The combined company will be led by Decoy’s Co-founders, Chief Executive Officer Frederick “Rick” Pierce and Chief Scientific Officer Barbara Hibner, by Decoy’s Chief Business Officer Peter Marschel, Chief Technology Officer Mike Lipp, by acting Chief Medical Officer and Scientific Advisory Board Chair Shahin Gharakhanian, M.D. and by Salarius’ Acting Chief Executive Officer and Chief Financial Officer Mark Rosenblum.

During the next 12 months, Decoy expects to advance its lead asset, a pan-coronavirus antiviral, to the filing of an Investigational New Drug (IND) application with the U.S. Food and Drug Administration (FDA), and to make progress with its other programs including a broad-acting antiviral against flu, COVID-19 and respiratory syncytial virus (RSV), and a peptide drug conjugate targeting GI cancers.

Also during this time, data may be reported from an investigator-initiated Phase 1/2 clinical study at MD Anderson Cancer Center evaluating Salarius’ seclidemstat as a potential treatment for myelodysplastic syndrome and chronic myelomonocytic leukemia in patients with limited treatment options.

Decoy Therapeutics is a preclinical-stage biotechnology company that is leveraging machine learning and artificial intelligence tools alongside high-speed synthesis techniques to rapidly design, engineer and manufacture peptide conjugate drug candidates that target serious unmet medical needs. The company’s initial pipeline is focused on respiratory viruses and GI cancers. Decoy has attracted financing from institutional investors as well as significant non-dilutive capital from the Massachusetts Life Sciences Seed Fund, the Google AI startup program and the NVIDIA Inception program among other sources. The company has also received QuickFire Challenge award funding provided by the Biomedical Advanced Research and Development Authority (BARDA) through BLUE KNIGHT™, a collaboration between Johnson & Johnson Innovation – JLABS and BARDA within the Administration for Strategic Preparedness and Response. For more information, please visit www.DecoyTx.com.

Salarius Pharmaceuticals is a clinical-stage biopharmaceutical company with two drug candidates for patients with cancer in need of new treatment options. Salarius’ product portfolio includes seclidemstat, the company’s lead candidate, which is being studied in an investigator-initiated Phase 1/2 clinical study in hematologic cancers underway at MD Anderson Cancer Center as a potential treatment for MDS) and chronic myelomonocytic leukemia (CMML) in patients with limited treatment options. SP-3164, the company’s IND-stage second asset, is an oral small molecule protein degrader. Salarius previously received financial support for seclidemstat for the treatment of Ewing sarcoma from the National Pediatric Cancer Foundation and was a recipient of a Product Development Award from the Cancer Prevention and Research Institute of Texas (CPRIT). For more information, please visit www.salariuspharma.com.

This communication shall not constitute an offer to sell or the solicitation of an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No public offer of securities in connection with the merger shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.

This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 regarding Salarius, Decoy, the proposed merger, Salarius’ ability to regain compliance with the Nasdaq continued listing requirements and other matters, including without limitation, statements relating to plans and expectations relating to the business, scientific advisory board, products, including expected achievement of milestones for its lead asset and future prospects of Salarius, Decoy and the combined company. These statements may discuss goals, intentions and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Salarius, as well as assumptions made by, and information currently available to, management. Forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as “may,” “will,” “should,” “would,” “expect,” “anticipate,” “plan,” “likely,” “believe,” “estimate,” “project,” “intend,” and other similar expressions.

Statements that are not historical facts are forward-looking statements. Forward-looking statements are based on current beliefs and assumptions that are subject to risks and uncertainties and are not guarantees of future performance. Actual results could differ materially from those contained in any forward-looking statement as a result of various factors, including, without limitation: the risk that the conditions to the closing are not satisfied, including uncertainties as to the timing of the consummation of the proposed merger; the ability of each of Salarius and Decoy to consummate the merger; risks and uncertainties related to Salarius’ ability to regain compliance with the Nasdaq continued listing standards in the required timeframe; risks related to the combined company’s ability to satisfy the initial listing standards in the required timeframe; Salarius may not receive any additional extensions from Nasdaq if Salarius is unable to regain compliance within the required timeframe; risks related to Salarius’ ability to estimate and manage its operating expenses and its expenses associated with the proposed merger pending the closing; risks that the combined company will not achieve the synergies expected from the proposed merger; risks that Salarius and the combined company will not obtain sufficient financing to execute on their business plans and risks related to Decoy’s products and development plans, including unanticipated issues with any IND application process and the potential of the IMP3ACT™ platform. Readers are urged to carefully review and consider the various disclosures made by Salarius in its reports filed with the SEC, including its Annual Report on Form 10-K for the fiscal year ended December 31, 2024, as revised or supplemented by its Quarterly Reports on Form 10-Q and other documents filed with the SEC. If one or more of these risks or uncertainties materialize, or if the underlying assumptions prove incorrect, Salarius’ actual results may vary materially from those expected or projected.

Alliance Advisors IR

Jody Cain

jcain@allianceadvisors.com

310-691-7100

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