Plus Therapeutics is a clinical-stage biopharmaceutical and diagnostics company focused on CNS cancers. Its lead drug candidate, REYOBIQ (rhenium Re-186 obisbemeda), is a radioactive drug designed to treat recurrent glioblastoma (GBM), leptomeningeal metastases (LM), and pediatric brain cancers. Rather than external beam radiation therapy, REYOBIQ is injected directly into or near the tumor via standard neurosurgical catheters, concentrating radiation at the site of disease and minimizing exposure to surrounding healthy tissue. REYOBIQ is in Phase 2 trials for recurrent GBM and Phase 1/2 for LM, with a pediatric brain cancer trial expected to begin in 2026. The company also operates CNSide Diagnostics, a wholly owned subsidiary that offers a CSF-based laboratory test to detect and monitor cancer that has spread to the CNS — primarily targeting LM. CNSide re-launched commercially in Texas in August 2025 and has secured payor agreements with UnitedHealthcare and Humana. Plus Therapeutics is pre-revenue on its drug pipeline, and its current revenue consists primarily of government grants from CPRIT, NIH/NCI, and the DoD, which fund a significant share of its clinical trial costs. If REYOBIQ is approved, revenue would come from per-treatment sales to hospitals. CNSide generates revenue through lab test reimbursements from commercial insurers. The company operates with 28 full-time employees and relies on grant funding and periodic equity raises to sustain operations.