Polaryx Therapeutics Activates First Clinical Trial Site for SOTERIA Phase 2 Basket Trial of PLX-200

Boys Town National Research Hospital in Nebraska becomes first activated site in study targeting four rare pediatric lysosomal storage disorders and has now initiated patient screening as Polaryx advances toward first patient dosing

PARAMUS, N.J., Nov. 09, 2026 (GLOBE NEWSWIRE) -- Polaryx Therapeutics, Inc. (Nasdaq: PLYX) ("Polaryx" or the "Company"), a clinical-stage biotechnology company developing novel, disease-modifying therapies for rare pediatric lysosomal storage disorders (LSDs), today announces the activation of the first clinical trial site for SOTERIA, its Phase 2 basket trial evaluating the Company's lead investigational drug candidate, PLX-200, across four rare pediatric LSDs.  Boys Town National Research Hospital in Boys Town, Nebraska, where the study is being led by Isabella Herman, M.D., Ph.D., a pediatric neurologist and neurogeneticist, is now positioned to begin protocol-directed screening of eligible pediatric participants for SOTERIA. Boys Town is an affiliate center in the Batten Disease Support, Research, and Advocacy (BDSRA) Foundation's Batten Disease Clinical Center of Excellence Program and provides multidisciplinary care for children with rare neurogenetic disorders.

"The activation of our first SOTERIA site represents an important step in translating the groundwork we have completed into clinical execution," said Alex Yang, Polaryx Therapeutics’ Chair and Chief Executive Officer. "For a study addressing several ultra-rare pediatric diseases, each participating center plays a meaningful role in identifying eligible patients and supporting families throughout the trial. We are pleased to begin this next phase with the experienced team at Boys Town as we work toward our first patient dosing milestone."

“As a pediatric neurogeneticist specializing in precision medicine, I have witnessed firsthand the devastating impact that rare neurodegenerative diseases have on children and their families,” said Isabella Herman, M.D., Ph.D., the investigator leading SOTERIA at Boys Town National Research Hospital. “For patients living with CLN2 and CLN3 Batten disease, Krabbe disease, and Sandhoff disease, the need for effective treatments is urgent. The SOTERIA trial investigating PLX-200 represents an important opportunity to explore a potential disease-modifying therapy that could one day help preserve function, slow disease progression, and give families more meaningful time together. We are incredibly proud to be the first site activated for this trial, bringing innovative research closer to the families who need it most. Every child deserves a chance at a better future, and initiatives like SOTERIA reflect our commitment to turning advances in precision medicine into meaningful hope for patients and families.”

SOTERIA is designed to evaluate the safety, tolerability, pharmacokinetics and clinical activity of orally administered PLX-200 in children with CLN2 disease, CLN3 disease, Krabbe disease and Sandhoff disease. The multicenter, open-label study includes an initial sentinel group to support early safety assessment before broader enrollment. All five remaining planned U.S. sites are on track to be activated by the end of the first quarter of 2027, bringing the total number of U.S. sites to six. Polaryx also submitted a clinical trial application to both the European Union’s European Medicines Agency (EMA) and the United Kingdom’s Medicines and Healthcare products Regulatory Agency (MHRA) in October 2026, seeking approval to conduct SOTERIA in the European Union and United Kingdom in the first quarter of 2027.

"Boys Town brings specialized expertise in pediatric neurology and rare genetic diseases, along with close relationships across the Batten disease community," said Will Charlton, M.D., M.A.S., Polaryx Therapeutics’ Chief Medical Officer. "With the first site activated, our immediate focus is on protocol-based screening and enrollment while continuing to prepare additional sites. We are grateful for the commitment of the investigators, clinical teams and families who make rare disease research possible."

PLX-200 has received FDA Fast Track Designation for each of the four indications being evaluated in SOTERIA. The Company previously received authorization from the FDA to proceed with the study and registered the trial on ClinicalTrials.gov under identifier NCT07740512.

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 to inform 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; the timing for initiation of the SOTERIA trial; and potential benefits of PLX-200. 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 recent Form 10-K, Quarterly Reports on Form 10-Q, and other filings 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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