• Multiple long-term LM survivors in those patients receiving multiple doses of REYOBIQ
• RNA sequencing data show early tumor apoptosis and activation of innate immune responses
• Updated ReSPECT data presented at the 2025 Nuclear Medicine and Neurooncology Conference

Plus Therapeutics, a clinical-stage pharmaceutical company developing targeted radiotherapeutics with advanced platform technologies for central nervous system (CNS) cancers, announces the presentation of new data on its lead drug REYOBIQ™ (rhenium Re186 obisbemeda) during both an oral presentation and a poster presented at the Nuclear Medicine and Neurooncology Conference. The meeting was held May 9-10, 2025 in Vienna, Austria.

“This newly presented data shows safety, clinical benefit and data supporting the underlying mechanism of action for REYOBIQ in patients with Leptomeningeal Metastases,” said Marc H. Hedrick, M.D., Plus Therapeutics President and Chief Executive Officer. “Furthermore, multiple doses of REYOBIQ were administered under compassionate use, mirroring how REYOBIQ may one day be used post approval and can contribute to long term survival in LM.”

The study, titled, “Rhenium Obisbemeda (REYOBIQ) in Leptomeningeal Metastases,” highlights additional data from the Company’s now complete Phase 1 ReSPECT-LM dose escalation trial. The presented data added further detail to the previously reported data from the submitted abstract, which demonstrated:

• Dose dependent increase in the average absorbed dose to the cranial and spinal subarachnoid space reaching 253Gy in Cohort 5
• Neuroimaging response data was available for 17 patients as of the data cutoff with five of those (29%) showing a partial response
• An additional eight patients showed stable disease by neuroimaging through day 112 for a Clinical Benefit Rate (complete response + partial response + stable disease) of 76% (13/17 – five partial responses and eight stable disease). Additionally, 87% of subjects demonstrated clinical response based on the physician evaluation (13/15 – 2 response and 11 stable disease)
• No dose limiting toxicity (DLT) observed in the first four cohorts, with a grade 4 DLT (thrombocytopenia), one in each of Cohorts 5 and 6
• RNA sequencing of LM cells showed early induction of apoptosis, with an innate immune response followed by an increase in T cells and an adaptive immune response by Day 28.
• In addition, of the seven patients who received a response of better than 80% in reduction of LM tumor cells in the cerebrospinal fluid, five survived at least one year following initial treatment.
• The study reports that three of those five were retreated via compassionate use.

Source – Globe Newswire