Core Insights - Plus Therapeutics, Inc. presented promising data on Rhenium (186Re) Obisbemeda for treating leptomeningeal disease, particularly in breast cancer patients, at the 2024 San Antonio Breast Cancer Symposium [1][2] Group 1: Clinical Trial Results - In the ReSPECT-LM Phase 1 clinical trial, 9 out of 20 patients with leptomeningeal metastases (LM) from primary breast cancer were treated, with the maximum tolerated dose not yet reached [3] - The patients received a single intrathecal dose of Rhenium (186Re) Obisbemeda, ranging from 6.6 to 66.14 mCi of radiation, with only one dose-limiting toxicity (thrombocytopenia) reported [3] - Best response rates included circulating tumor cell (CTC) response at 88% (7/8), MRI imaging response at 25% (2/8), and clinical response at 29% (2/7) [3] - Clinical benefit rates showed CTC at 100% (8/8), MRI imaging at 75% (6/8), and clinical at 71% (5/7) [3] - The median overall survival for the 9 breast cancer patients was 9 months, with 2 patients surviving beyond 600 days post-treatment [3] Group 2: Future Plans - The company plans to initiate a ReSPECT-LM Phase 1b single-dose breast expansion cohort in Q1 2025 to further evaluate the safety and efficacy of Rhenium (186Re) Obisbemeda [4] - Plus Therapeutics aims to rapidly advance into a breast cancer-focused expansion cohort alongside planned multiple-dose expansion trials [4] Group 3: Background on Leptomeningeal Metastases - Leptomeningeal metastases (LM) is a rare but serious complication of cancer, with breast cancer being the most common primary cancer associated with LM, affecting 3-5% of breast cancer patients [5][6] - The incidence of LM is increasing, partly due to longer survival rates of cancer patients and the ineffectiveness of standard chemotherapies in reaching sufficient concentrations in the cerebrospinal fluid [6] Group 4: About Rhenium (186Re) Obisbemeda - Rhenium (186Re) Obisbemeda is a novel injectable radiotherapy designed for targeted high-dose radiation delivery in CNS tumors, optimizing patient outcomes [7] - The radioisotope Rhenium-186 is noted for its short half-life and effectiveness in destroying cancerous tissue while allowing for real-time imaging [7] - The drug is currently being evaluated in clinical trials for recurrent glioblastoma and leptomeningeal metastases, with funding support from the National Cancer Institute and the Cancer Prevention & Research Institute of Texas [7] Group 5: Company Overview - Plus Therapeutics, Inc. is focused on developing targeted radiotherapeutics for challenging CNS cancers, aiming to enhance clinical outcomes through innovative treatment approaches [8] - The company has established a supply chain through strategic partnerships to support the development and potential commercialization of its products [8]
Plus Therapeutics Presents Positive ReSPECT-LM Phase 1 Interim Data for Breast Cancer Patients with Leptomeningeal Metastases at the 2024 San Antonio Breast Cancer Symposium