Plus Therapeutics’ Rhenium Obisbemeda shows safety, potential efficacy

Plus Therapeutics presented an update on the ongoing ReSPECT-GBM Phase 1/2 clinical trial evaluating the company’s lead asset Rhenium Obisbemeda for the treatment of recurrent glioblastoma. The data highlights the continued favorable safety profile and encouraging efficacy results of Rhenium Obisbemeda in a patient population with historically poor prognosis. ReSPECT-GBM is a first-in-human, open-label, Phase 1/2 study investigating feasibility, dose escalation, and critical convection enhanced delivery parameters to determine the maximum tolerated dose, maximum feasible dose, safety, and potential efficacy of Rhenium (186Re) Obisbemeda in recurrent adult glioma. Rhenium (186Re) Obisbemeda continues to show a favorable safety profile in the 42 enrolled patients; one dose-limiting toxicity has been reported, which was observed in Cohort 8. In Phase 2, most adverse events were mild or moderate, and largely unrelated or unlikely related to the drug. To date, 88.9% of Phase 2 patients met key CED drug delivery parameters shown to correlate with overall survival, achieving a tumor absorbed dose greater than100 Gy and radiation coverage of greater than70%. In terms of objective tumor response based on quantitative image analysis, a statistically significant reduction in tumor volume rate change was seen in tumors receiving greater than 100 Gy absorbed dose. Sufficient tumor coverage correlated with tumor control, while regrowth occurred outside treated areas.