Plus Therapeutics Reports First Quarter 2026 Financial Results and Provides Business Update on REYOBIQ™ Clinical Program and CNSide® Commercial Rollout

Plus Therapeutics Advances REYOBIQ Program and Expands CNSide Commercial Reach

Plus Therapeutics announced its Q1 2026 financial results and provided business updates. Key highlights include completing an upsized public offering generating $15 million, strengthening its leadership team, and advancing its REYOBIQ™ clinical program. REYOBIQ received U.S. FDA Orphan Drug Designation for pediatric malignant gliomas and a Category III CPT reimbursement code for convection-enhanced delivery in recurrent glioblastoma and pediatric brain cancer. The company also expanded CNSide® CSF Assay Platform's commercial rollout, securing a unique PLA code for Medicare billing and increasing payer coverage to approximately 81 million covered lives, including Blue Shield of California. Cash and investments stood at $15.1 million as of March 31, 2026.

• Financial Performance and Capital Infusion: Plus Therapeutics significantly bolstered its financial position by completing an upsized public offering, which generated $15 million in gross proceeds. This increased the company's cash and investments balance to $15.1 million as of March 31, 2026, up from $8.6 million at the end of 2025. This capital infusion is crucial for supporting the commercialization of CNSide and advancing its two ongoing Phase 2 clinical programs, demonstrating strong investor confidence and providing resources for key strategic initiatives.
• Regulatory and Market Access Achievements for REYOBIQ™: The company achieved significant regulatory milestones for REYOBIQ™, including U.S. FDA Orphan Drug Designation for pediatric malignant gliomas, which was broadened to include progressive pediatric ependymoma. Additionally, securing an American Medical Association Category III CPT reimbursement code for convection-enhanced delivery with REYOBIQ™ is a critical step, unlocking market access and growth potential for the therapy in recurrent glioblastoma and pediatric brain cancer, paving the way for broader adoption.
• Expansion of CNSide® Commercial Rollout and Payer Coverage: Plus Therapeutics made substantial progress in the commercialization of its CNSide® CSF Assay Platform. This includes receiving a unique PLA code for Medicare billing and successfully enrolling CNSide with Medicare, which is vital for reimbursement. Furthermore, new payer coverage agreements, notably with Blue Shield of California, have expanded total U.S. covered lives to approximately 81 million, significantly increasing market reach and access for this precision diagnostic tool.

Shaping the Future of Pediatric Malignant Glioma Treatment

The treatment landscape for pediatric malignant gliomas has witnessed significant innovation through the emergence of oncolytic viral therapy (OVT) as a promising therapeutic modality. A systematic review published in 2025 identified four clinical trials conducted through December 2023, encompassing 40 pediatric patients with a median age of 14.5 years diagnosed with various malignant gliomas including glioblastoma, diffuse intrinsic pontine glioma, anaplastic astrocytoma, recurrent ependymoma, and diffuse hemispheric glioma. These trials investigated multiple oncolytic agents including HSV G-207, DNX-2401, AdV-tk, and Lerapolturev, representing a diversified approach to viral-based cancer therapy in the pediatric population.

Clinical outcomes from these trials demonstrated encouraging survival metrics, with overall survival ranging from 4.1 to 47.7 months and progression-free survival spanning 1.7 to 47.7 months. The safety profile of oncolytic viral therapy proved favorable, with most adverse events being mild and including fever, headache, and nausea. Serious adverse events remained infrequent and were predominantly attributed to underlying disease progression rather than treatment-related toxicity. Importantly, many patients in these trials continued to receive standard multimodal therapies including surgery, radiotherapy, and chemotherapy, suggesting that OVT may serve as a complementary rather than replacement therapeutic approach.

Despite these advances, significant challenges persist in pediatric malignant glioma treatment, as childhood mortality remains elevated among this patient population. Traditional therapeutic interventions including surgical resection, chemotherapy, and radiotherapy continue to demonstrate inherent limitations in achieving durable disease control. While oncolytic viral therapy has shown safety and feasibility with signals of clinical benefit in selected patients, the field requires larger, controlled trials to establish definitive survival benefits and develop optimal therapeutic strategies for this devastating disease.

Dual Momentum: Precision CNS Diagnostics and Targeted Brain Cancer Therapies

The recent updates from Plus Therapeutics underscore a dual momentum in addressing some of the most challenging central nervous system (CNS) cancers. On one front, the REYOBIQ program is making strides in the high-need areas of pediatric malignant gliomas and recurrent glioblastoma. The U.S. FDA Orphan Drug Designation provides crucial incentives for developing therapies for these rare conditions, while the securing of a Category III CPT reimbursement code for convection-enhanced delivery (CED) is a significant de-risker. This code establishes a clear pathway for reimbursement of the specialized delivery method, which is vital for the eventual commercial viability of REYOBIQ, though its ultimate success will hinge on robust clinical efficacy and safety data from ongoing trials.

Simultaneously, the CNSide® CSF Assay Platform is rapidly gaining traction as a transformative diagnostic tool for leptomeningeal disease (LMD). Clinical literature consistently highlights CNSide's superior sensitivity in detecting LMD compared to traditional methods like CSF cytology and MRI, often identifying cases missed by standard approaches. This enhanced diagnostic capability allows for earlier detection and more informed treatment decisions. Furthermore, CNSide's ability to characterize CSF-derived tumor cells and cell-free DNA for actionable mutations, which can be discordant with primary tumor sites, opens new avenues for personalized anti-cancer therapies. The recent acquisition of a unique PLA code for Medicare billing and expanded payer coverage to approximately 81 million lives, including Blue Shield of California, are pivotal for accelerating commercial adoption and ensuring broader patient access. However, while the diagnostic sensitivity is clear, the full clinical utility of detecting these discordant mutations and how they translate to improved patient outcomes requires further validation in larger studies. The long-term commercial success of CNSide will also depend on sustained payer acceptance and its ability to maintain differentiation within an evolving liquid biopsy landscape. This dual progress positions the company to potentially redefine both diagnostic and therapeutic paradigms in complex CNS malignancies.