Plus Therapeutics reports positive Phase 1 trial data of rhenium obisbemeda

Plus Therapeutics reported positive data from the ReSPECT-LM clinical study evaluating the company’s lead radiotherapeutic, rhenium obisbemeda, for the treatment of leptomeningeal metastases – LM – at the Society for Neuro Oncology/American Society of Clinical Oncology Cancer Conference taking place August 10-12 in San Francisco. CEO Marc Hedrick said, “Similar to our promising Phase 1 and 2 data for glioblastoma, this most recent data indicates that LM, which is ten times more common than glioblastoma, may be similarly addressable with targeted radiotherapy using rhenium obisbemeda.” Ten treated patients received a single escalating dose of rhenium obisbemeda. No dose limiting toxicities were observed and a maximum tolerated dose or maximum feasible dose was not reached. Most adverse events were mild or moderate, with the majority not related to treatment. Currently, 5 of the 10 treated patients remain alive with a median overall survival of 10 months. The FDA has approved continued dose escalation. CSF tumor cell counts decreased from pre-dose levels 28 days after treatment by up to 91%, mean decrease 53%. Increases in administered dose correlated with linear increases in absorbed dose to the target tissue.