Plus Therapeutics Presents Positive Interim ReSPECT-LM Phase 1 Data for Leptomeningeal Metastases at 2024 SNO/ASCO CNS Metastases Conference

Clinical Trial Update - The ReSPECT-LM Phase 1 dose escalation study for Rhenium (186Re) Obisbemeda showed feasibility, safety, and a response in circulating tumor cells (CTCs) in leptomeningeal disease (LM) patients, with a median overall survival of 12 months [1][3] - The trial treated 16 patients across 4 cohorts, with no dose-limiting toxicities observed and the maximum tolerated dose not reached [3] - A mean reduction of 53% in CSF circulating tumor cells (CTCs) was observed at 28 days post-treatment compared to baseline [3] - The mean absorbed radiation dose to the ventricles and cranial subarachnoid space was 156 Gy in Cohort 4, compared to 1 Gy to the spleen [3] FDA Designations - Rhenium (186Re) Obisbemeda received Fast Track designation from the FDA for the treatment of LM [3] - The FDA also granted Orphan Drug designation to Rhenium (186Re) Obisbemeda for the treatment of LM in breast cancer patients [3] Funding and Support - The ReSPECT-LM clinical trial is partially funded by a 3-year, 17.6 million grant from the Cancer Prevention & Research Institute of Texas (CPRIT) [4][7] - ReSPECT-GBM, another clinical trial evaluating Rhenium (186Re) Obisbemeda, is supported by an award from the National Cancer Institute (NCI) [7] About Leptomeningeal Metastases (LM) - LM is a rare complication of cancer where the primary cancer spreads to the cerebrospinal fluid (CSF) and leptomeninges surrounding the brain and spinal cord [5] - Breast cancer is the most common cancer linked to LM, with 3-5% of breast cancer patients developing LM [5] - LM occurs in approximately 5% of cancer patients, with a 1-year survival rate of 7% and a 2-year survival rate of 3% [5] - The incidence of LM is increasing due to longer cancer patient survival and the inability of standard chemotherapies to reach sufficient concentrations in the spinal fluid [6] About Rhenium (186Re) Obisbemeda - Rhenium (186Re) Obisbemeda is a novel injectable radiotherapy designed to deliver targeted high-dose radiation to CNS tumors safely and effectively [7] - Rhenium-186 is an ideal radioisotope for CNS therapeutic applications due to its short half-life, beta energy for destroying cancerous tissue, and gamma energy for real-time imaging [7] About Plus Therapeutics - Plus Therapeutics is a clinical-stage pharmaceutical company developing targeted radiotherapeutics for difficult-to-treat CNS cancers, including recurrent glioblastoma (GBM) and leptomeningeal metastases (LM) [8] - The company has built a supply chain through strategic partnerships to enable the development, manufacturing, and potential commercialization of its products [8] About CPRIT - The Cancer Prevention & Research Institute of Texas (CPRIT) was established in 2007 and has been awarded an additional 3 billion in 2019, bringing its total investment in cancer research and prevention to $6 billion [9] - CPRIT has awarded over$3 billion in grants to Texas research institutions and organizations, supporting the recruitment of 281 distinguished researchers and the establishment or relocation of 52 companies to Texas [10]