Company on track to initiate SOTERIA trial in the second half of 2026

Clinical development activities advancing following FDA authorization, CRO engagement and Fast Track Designation across all four planned indication

PARAMUS, NJ, Aug. 25, 2026 (GLOBE NEWSWIRE) -- Polaryx Therapeutics, Inc. (NASDAQ:PLYX), a clinical-stage biotechnology company developing novel, disease-modifying therapies for rare pediatric lysosomal storage disorders ("LSDs"), today provided an operational readiness update for SOTERIA, its Phase 2 basket trial evaluating lead candidate PLX-200 across four rare pediatric LSDs.

Polaryx continues to advance clinical trial start-up activities in collaboration with its contract research organization (CRO) and remains focused on initiating SOTERIA in the fourth quarter of 2026. The Company has established several key elements supporting trial initiation, including receipt of authorization from the U.S. Food and Drug Administration (FDA) to proceed with SOTERIA, engagement of an experienced CRO to support trial execution, FDA Fast Track Designation for PLX-200 across all four indications planned for the study, and completion of a $10 million financing intended to support initiation of SOTERIA and key planned clinical milestones. As part of its ongoing clinical development activities, SOTERIA has also been registered on ClinicalTrials.gov under study identifier NCT07740512 which, among other important information, provides information related to eligibility; participating site information will be made available and updated as sites are activated.

"With the key regulatory, clinical and financial elements supporting SOTERIA in place, our focus is increasingly on clinical execution," said Alex Yang, Chair and Chief Executive Officer of Polaryx Therapeutics. "SOTERIA represents the cornerstone of our near-term development strategy for PLX-200 and provides an efficient opportunity to evaluate a single oral drug candidate across four devastating pediatric lysosomal storage disorders. We believe the progress made to date positions us well as we continue advancing toward initiation of the trial in the fourth quarter of this year."

SOTERIA is a Phase 2, open-label, multicenter basket trial designed to evaluate the safety, tolerability, pharmacokinetics and clinical activity of PLX-200 in pediatric patients with CLN2 disease, CLN3 disease, Krabbe disease and Sandhoff disease. The study is designed to enroll participants between two and 15 years of age across the four disease cohorts.

The trial incorporates a sentinel group designed to provide an early assessment of safety and tolerability before enrollment proceeds across the broader study population. Following screening and dose titration, participants are expected to enter a 96-week maintenance period. An interim analysis of 52-week maintenance data is also planned along with planned regular assessments of endpoints and biomarkers.

For the CLN2 and CLN3 cohorts, clinical activity will also be evaluated against established natural history data. This approach is intended to enable Polaryx to assess potential treatment effects in the context of the expected course of these progressive diseases and may help inform subsequent clinical and regulatory development strategies.

"SOTERIA has been intentionally designed to provide flexibility while generating meaningful information across multiple LSD indications," continued Mr. Yang. "Our objective is to efficiently identify the indications in which PLX-200 may demonstrate the greatest potential and use those findings to inform the most appropriate development path for the program. With Fast Track Designation across each of the four initial indications, we are well positioned to maintain an active dialogue with the FDA as clinical data emerge."

About the SOTERIA Trial

SOTERIA is a Phase 2, open-label, single arm trial intended to assess the safety, tolerability, and clinical activity of Polaryx’s lead drug candidate, PLX-200, in CLN2, CLN3, Krabbe disease, and Sandhoff disease, four different LSDs whose patient populations Polaryx believes represent approximately one quarter of the LSD population. SOTERIA is designed to be flexible, resource-efficient, and provide important data and information important to PLX-200’s future clinical development. Polaryx received a safe to proceed letter in October 2025 from the FDA and plans to initiate SOTERIA in the fourth quarter of 2026 in trial sites in the United States as well as in Europe and Asia or other foreign jurisdictions. Designed with a high degree of flexibility, SOTERIA represents a resource-efficient opportunity to validate PLX-200’s preclinical science across multiple LSDs while gathering data that will be invaluable in planning PLX-200’s future development pathway, including the initiation of potentially pivotal trials. For the CLN2 and CLN3 cohorts, although the entire trial is open label, these cohorts will incorporate analyses comparing natural history data as a control arm to PLX-200’s treated arm. A natural history study is a preplanned observational study intended to track the course of the disease. Should the data demonstrate compelling clinical activity, Polaryx may pursue an expedited approval pathway. For more information about the SOTERIA trial, please visit https://clinicaltrials.gov/study/NCT07740512.

About Polaryx Therapeutics

Polaryx Therapeutics, Inc. is a clinical-stage biotechnology company focused on developing patient-friendly small molecule and gene therapy treatments for rare orphan lysosomal storage disorders (LSDs). Founded in 2014, Polaryx seeks to deliver safe, effective, and patient-friendly treatments that address the underlying pathophysiology of these catastrophic diseases and their significant unmet need. Our approach integrates small molecule therapies, including a combination therapy, and a gene therapy, positioning us to potentially address both the genetic and downstream pathological features of LSDs. Our small molecule drug candidates share similar modes of action that have been demonstrated to address lysosomal dysfunction, neuroinflammation, and neuronal loss in our validated animal models that closely mimic human clinical phenotypes. Our most advanced product candidate, PLX-200, targets several LSDs and we intend to launch SOTERIA, a Phase 2 basket trial, to evaluate PLX-200’s safety and efficacy in the fourth quarter of 2026. For more information about the SOTERIA trial, please visit https://clinicaltrials.gov/study/NCT07740512. More information about Polaryx may be found at www.polaryx.com.

Forward-Looking Statements

Certain statements in this press release may constitute "forward-looking statements" within the meaning of the federal securities laws, including, but not limited to, statements regarding: Polaryx’s clinical development plans for its product candidates, including PLX-200, including the timing for initiation of the SOTERIA trial. Words such as "may," "might," "will," "objective," "intend," "should," "could," "can," "would," "expect," "believe," "design," "estimate," "predict," "potential," "develop," "plan" or the negative of these terms, and similar expressions, or statements regarding intent, belief, or current expectations, are forward-looking statements. While Polaryx believes these forward-looking statements are reasonable, undue reliance should not be placed on any such forward-looking statements, which are based on information available to the company on the date of this release. These forward-looking statements are based upon current estimates and assumptions and are subject to various risks and uncertainties (including, without limitation, those set forth in Polaryx’s filings with the U.S. Securities and Exchange Commission (the SEC), many of which are beyond the Company’s control and subject to change. Actual results could be materially different. Risks and uncertainties include: global macroeconomic conditions and related volatility, expectations regarding the initiation, progress, and expected results of Polaryx’s clinical trials; expectations regarding the timing, completion and outcome of Polaryx’s clinical trials; the timing or likelihood of regulatory filings and approvals; liquidity and capital resources; and other risks and uncertainties identified in Polaryx’s most recently filed Form 10-K with the SEC and subsequent disclosure documents Polaryx may file with the SEC. Polaryx claims the protection of the Safe Harbor contained in the Private Securities Litigation Reform Act of 1995 for forward-looking statements. Polaryx expressly disclaims any obligation to update or alter any statements whether as a result of new information, future events or otherwise, except as required by law.

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