HOUSTON, April 02, 2026 (GLOBE NEWSWIRE) -- 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.

"Securing coverage with Highmark, a leading Blue Cross Blue Shield-affiliated payer, marks another important milestone in expanding patient access to CNSide and reinforces the growing recognition among payers of its clinical and economic value," said Russ Havranek, EVP Corporate and Commercial Strategy at Plus Therapeutics. "We continue to make progress toward broad national coverage and expanded adoption."

The CNSide® CSF Assay Platform enables earlier, and more accurate detection and monitoring of leptomeningeal metastases compared to conventional CSF cytology, supporting rapid diagnosis, treatment monitoring, and treatment guidance. The superior clinical utility of CNSide® over standard of care has been demonstrated in 9 peer-reviewed publications, the FORESEE clinical trial, and demonstrated in real-world practice. Earlier detection enabled by CNSide has been shown in health economic analyses to reduce overall leptomeningeal metastases-related healthcare costs by ~40%, driven by earlier detection and treatment optimization.

Since its commercial launch, more than 11,000 CNSide tests have been performed at over 120 U.S. cancer institutions since 2020, delivering high sensitivity (92%) and specificity (95%), while influencing treatment decisions in 90% of cases.

This test is available exclusively through CNSide Diagnostics, LLC as a testing service provided to health care professionals in the U.S.

About CNSide Diagnostics, LLC

CNSide Diagnostics, LLC is a wholly owned subsidiary of Plus Therapeutics, Inc. that develops and commercializes proprietary laboratory-developed tests, such as CNSide®, designed to identify tumor cells that have metastasized to the central nervous system in patients with carcinomas and melanomas. The CNSide® CSF Assay Platform enables quantitative analysis of the cerebrospinal fluid that informs and improves the management of patients with leptomeningeal metastases. For more information, visit https://www.cnside-dx.com/.

About Plus Therapeutics

Headquartered in Houston, Texas, Plus Therapeutics, Inc. is a clinical-stage pharmaceutical company developing targeted radiotherapeutics for difficult-to-treat cancers of the central nervous system with the potential to enhance clinical outcomes. Combining image-guided local beta radiation and targeted drug delivery approaches, the Company is advancing a pipeline of product candidates with lead programs in leptomeningeal metastases (LM) and recurrent glioblastoma (GBM). The Company has built a supply chain through strategic partnerships that enable the development, manufacturing, and future potential commercialization of its products. For more information, visit https://www.plustherapeutics.com.

About Highmark

An independent licensee of the Blue Cross Blue Shield Association, Highmark Inc., together with its Blue-branded affiliates, collectively comprise the fifth largest overall Blue Cross Blue Shield-affiliated organization in the country with nearly 8 million members nationwide. Its diversified businesses serve group customer and individual needs across the United States through dental insurance and other related businesses. For more information, visit www.highmark.com.

Forward-Looking Statements

This press release contains statements that may be deemed "forward-looking statements" within the meaning of U.S. securities laws, including statements regarding clinical trials, expected operations and upcoming developments. All statements in this press release other than statements of historical fact are forward-looking statements. These forward-looking statements may be identified by future verbs, as well as terms such as "expect," "potential," "anticipating," "planning" and similar expressions or the negatives thereof. Such statements are based upon certain assumptions and assessments made by management in light of their experience and their perception of historical trends, current conditions, expected future developments and other factors they believe to be appropriate. These statements include, without limitation, statements regarding the potential market for the CNSide CSF Assay, the timing in which the CNSide CSF Assay is commercially launched and commercialization is expanded, revenue and corporate profitability expectations including support reimbursements and payments for the CNSide CSF Assay, the development and utility of the CNSide CSF Assay and expectations as to the Company's future performance, including the next steps in developing the Company's product candidates.

Investor Contact

CORE IR

investor@plustherapeutics.com

Plus Therapeutics Secures Highmark Coverage for CNSide® CSF Assay, Expanding Reimbursement to ~75 Million Covered Lives