CNSide Diagnostics, LLC, a wholly-owned subsidiary of Plus Therapeutics, Inc. (Nasdaq: PSTV) ("Plus" or the "Company"), today announces a new payer coverage agreement with Highmark, effective April 1, 2026, providing reimbursement for its CNSide® Cerebrospinal Fluid (CSF) Tumor Cell Enumeration (TCE) assay for patients with metastatic central nervous system cancers. Highmark joins a growing list of national and regional payers, including United Healthcare and Humana, that provide coverage for CNSide.

The addition of Highmark expands CNSide's total covered lives from approximately 67 million to 75 million, representing continued progress toward the Company's 2026 objective of 150 million covered lives, while expanding patient access across the U.S. The agreement is expected to further accelerate adoption of CNSide across oncology centers by reducing reimbursement barriers for ordering physicians.