Plus Therapeutics presents results from ReSPECT-LM Phase 1 trial

Plus Therapeutics (PSTV) announces positive data from the ReSPECT-LM Phase 1 single dose escalation trial presented at the podium at the SNO/ASCO CNS Metastases Conference in Baltimore, MD. The data demonstrated treatment of leptomeningeal metastases with REYOBIQ is feasible, has a manageable safety profile, and shows a promising efficacy signal. The presentation, titled, “Phase 1 Dose Escalation of Rhenium Obisbemeda Rhenium Nanoliposome,186RNL for the Treatment of Leptomeningeal Metastases: Clinical Study Results for Safety and Efficacy,” highlighted study results to date from a total of 29 subjects in cohorts 1 – 6 who received 6.6 mCi, 13.2 mCi, 26.4 mCi, 44.10 mCi, 66.14 mCi, or 75mCi of REYOBIQ, respectively. Presented Data Highlights: Radiographic and clinical response rate of 76% and 87%, respectively, through day 112; CSF tumor cell enumeration assays showed a maximum reduction over baseline of 100% at day 28; Five of the 7 patients with a TCE response greater than80% survived at least 1 year; RNA sequencing of LM cells showed early induction of apoptosis, with an innate immune response followed by an adaptive immune response by day 28; Median overall survival of 9 months across cohorts 1-4 months, comparing favorably with literature reports of ~4 months; No dose-limiting toxicity was observed in cohorts 1-4, with 1 DLT in each of cohorts 5 and 6 of grade 4 cytopenia; The majority of adverse events across the trial were Grade 1 and 2; Mean absorbed dose to the cranial and spinal subarachnoid space was 272 Gy in cohort 6; A recommended phase 2 single dose of 44.1 mCi was determined