HOUSTON and LAKE FOREST, Calif., July 16, 2026 (GLOBE NEWSWIRE) -- Plus Therapeutics, Inc. (NASDAQ:PSTV) ("Plus" or the "Company") and Genomic Testing Cooperative, LCA ("GTC") today announced a collaboration to integrate GTC’s next-generation sequencing (NGS) technology into the CNSide^® cerebrospinal fluid (CSF) assay platform. The collaboration is expected to enable comprehensive DNA and RNA profiling across hundreds of clinically relevant biomarkers from a single CSF specimen, extending CNSide from guideline-recognized CTC enumeration into the guideline-recognized DNA and tumor-derived DNA analytic layer within one integrated platform. The collaboration advances Plus’ three-pillar CNS oncology strategy: targeted radiotherapeutics led by REYOBIQ^™ (rhenium Re186 obisbemeda); precision diagnostics anchored by the CNSide CSF platform; and AI-enabled data analytics through the Company’s strategic partnership with Ephemeral Technologies.

Leptomeningeal metastases (LM) occur in an estimated 5% to 10% of patients with metastatic solid tumors, representing a U.S. addressable population of more than 100,000 patients per year. The CNSide CSF Tumor Cell Enumeration test received dedicated AMA PLA code 0640U, effective July 1, 2026, and the CNSide CLIA laboratory is enrolled with Medicare. Commercial payer agreements covered approximately 126 million U.S. lives as of the Company’s most recent quarterly update. A recently presented health-economic analysis associated CNSide-enabled earlier diagnosis and management of LM with an approximately 40% reduction in overall LM-related healthcare costs.

Strategic Rationale

NCCN alignment. The updated NCCN CNS Cancers Guidelines (Version 2.2026) recognize CSF CTCs alongside tumor-derived DNA and broaden LM terminology from "CSF cytology" to "CSF analysis." CNSide already delivers guideline-recognized CTC enumeration; the GTC collaboration adds the guideline-recognized DNA and RNA layer within one CLIA-accredited testing platform
Foundational data layer. Hundreds of DNA and RNA biomarkers per CSF specimen, combined with CNSide tumor cell and biomarker quantification, create a uniquely deep longitudinal molecular data set, materially enhancing the inputs to Plus’ AI platform with Ephemeral Technologies
Expanded market and clinical utility. Positions CNSide as a comprehensive CSF-based precision oncology platform across LM and other metastatic CNS cancers, supporting broader adoption, higher per-test value, and potentially deeper biopharma engagement
Reimbursement leverage. Builds on PLA code 0640U and Medicare enrollment, with future billing pathways for the expanded menu pursued under applicable payer requirements
Operating leverage. Uses GTC’s sequencing and informatics as a technical service input to the CNSide CLIA laboratory, accelerating menu expansion while managing capital

"CNSide is central to building a leading precision oncology platform in metastatic CNS disease, and this collaboration is the foundation of the data intelligence engine that will define its next phase," said Russell Bradley, President and General Manager of CNSide Diagnostics, LLC. "The updated NCCN Guidelines’ recognition of CSF CTCs alongside tumor-derived DNA reinforces the clinical case for a comprehensive CSF molecular profiling platform. By adding comprehensive DNA and RNA profiling across hundreds of biomarkers, we expect to generate one of the most complete longitudinal molecular data sets in CNS oncology, expanding the addressable market and revenue per test, and creating durable data assets to support payer evidence, translational research, and pharmaceutical collaborations."

"Partnering with Plus Therapeutics extends our reach in CSF testing. Combining our cell-free DNA and RNA testing with CNSide CTC enumeration provides the most comprehensive evaluation of CSF," said Maher Albitar, M.D., Chief Executive Officer and Chief Medical Officer of Genomic Testing Cooperative. "Working with CNSide Diagnostics as the laboratory of record represents another expansion of our Cooperative business model. This model will help in building a uniquely rich standardized CSF-based molecular data resource for clinicians and researchers, aligned with the growing role of advanced CSF biomarkers reflected in the updated NCCN Guidelines."

About Plus Therapeutics

Plus Therapeutics, Inc. (NASDAQ:PSTV) is a specialty CNS oncology company integrating targeted radiotherapeutics, precision diagnostics, and AI-enabled data analytics for patients with central nervous system cancers. The Company’s lead investigational therapeutic is REYOBIQ^™ (rhenium Re186 obisbemeda), an injectable radiotherapy in clinical development for recurrent glioblastoma, leptomeningeal metastases, and pediatric brain cancers. Through its wholly owned subsidiary, CNSide Diagnostics, LLC, the Company commercializes the CNSide^® CSF assay platform as a laboratory developed test performed in a CLIA-certified clinical laboratory. The Company is also advancing a strategic AI partnership with Ephemeral Technologies to integrate its therapeutic, diagnostic, and bioinformatic data sets. For more information, visit www.plustherapeutics.com.

About Genomic Testing Cooperative

Genomic Testing Cooperative, LCA is an oncology diagnostic laboratory built around a cooperative business model that partners with laboratories, hospitals, oncology practices, and medical professionals to deliver comprehensive DNA and RNA genomic profiling using next-generation sequencing, informatics tools, and AI-enabled interpretation.

Forward-Looking Statements and Important Disclosures

CNSide is performed as a laboratory developed test (LDT) in the CNSide Diagnostics CLIA-certified laboratory and has not been cleared or approved by the FDA; REYOBIQ^™ is investigational and has not been approved by the FDA for any indication. References to the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines^®) are for informational purposes only; NCCN makes no warranties regarding their content, use, or application, does not endorse any product, therapy, or service, and the referenced update to the CNS Cancers Guidelines (Version 2.2026) does not constitute an endorsement of the CNSide^® CSF assay platform, any expanded CNSide menu, or the GTC collaboration. References to PLA code 0640U, Medicare enrollment, and commercial payer coverage are factual and do not constitute an endorsement by the AMA, CAP, CMS, or any payer, or a coverage determination for any expanded NGS-enabled CNSide menu that is not yet commercially available. The Company intends to conduct any menu expansion in compliance with applicable CLIA, FDA, CMS, AMA, CAP, and state requirements, with billing submitted by the CNSide CLIA laboratory under its PLA code. CPT^® is a registered trademark of the American Medical Association.

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, including statements regarding the anticipated benefits, scope, timing, and structure of the GTC collaboration; the number and clinical utility of DNA and RNA biomarkers to be assayed; CNSide Diagnostics serving as the laboratory of record and billing entity; the scope, timing, and clinical utility of any expanded CNSide menu; the size of the CNSide market opportunity and the Company’s 2026 commercial objectives; expectations regarding payer coverage, reimbursement, and billing code expansion; the development and potential approval of REYOBIQ^™; the anticipated benefits, scope, and timing of the Company’s strategic AI partnership with Ephemeral Technologies; the Company’s strategy of integrating diagnostics, therapeutics, and data analytics; the alignment of CNSide with evolving clinical practice guidelines, including the NCCN CNS Cancers Guidelines; and the Company’s future performance, strategy, and value creation. Forward-looking statements are based on current expectations and are subject to risks and uncertainties — including those relating to LDT regulation, PLA code single-laboratory and ADLT considerations, validation and commercialization of expanded CNSide menu offerings, payer coverage and reimbursement, REYOBIQ clinical and regulatory outcomes, performance and continuation of third-party collaborations (including with GTC and Ephemeral), evolution of clinical practice guidelines, data privacy and cybersecurity, capital availability, and macroeconomic and healthcare policy conditions — that could cause actual results to differ materially. Additional risk factors are described in the Company’s SEC filings, including its most recent Form 10-K and subsequent Forms 10-Q and 8-K, available at www.sec.gov. Readers are cautioned not to place undue reliance on these statements, which speak only as of the date of this release; the Company assumes no obligation to update them except as required by law. CNSide^® and REYOBIQ^™ are trademarks of Plus Therapeutics, Inc. or its subsidiaries.

Contacts

Investor Contact: CORE IR — investor@plustherapeutics.com | www.plustherapeutics.com/investors

Genomic Testing Cooperative Media Contact: Cara Stewart, WunderMarx Inc., +1 949-290-5563,

cara@wundermarx.com