Cerenome, the Houston company that traded as Plus Therapeutics until Aug. 3, 2026, presented two posters at the SNO/ASCO CNS Metastases Conference in Boston on Aug. 13 to 15: pharmacokinetic, dosimetry and early repeat-dosing safety data for Reyobiq (rhenium-186 obisbemeda) in leptomeningeal metastases, and a cost model for earlier diagnosis with its CNSide cerebrospinal fluid assay. Neither poster reports a controlled outcome.
- Company: Cerenome, Inc. (Nasdaq: CNSY), renamed from Plus Therapeutics (PSTV) effective Aug. 3, 2026.
- Reyobiq PK: drug redistributes within CSF in about 24 hours, clears the lateral ventricle with a 1.7-hour half-life.
- Pharmacodynamics: bulk RNA-seq shows apoptosis-gene induction at about 5 hours, peaking at 24 hours.
- Repeat dosing: Cohort 1a of ReSPECT-LMM cleared with no dose-limiting toxicities, enrollment continuing.
- CNSide model: LM-related costs estimated at roughly $119,550 a month, about $717,300 over six months, with a modeled 33% to 47% monthly reduction.
The therapeutic poster
Andrew Brenner, M.D., Ph.D., of The University of Texas Health Science Center at San Antonio presented "ReSPECT-LM: Pharmacokinetic and Pharmacodynamic Assessment of Rhenium Obisbemeda in Leptomeningeal Metastases with Emerging Data from Repeated Dosing (ReSPECT-LMM)." The analysis combined updated safety, activity, PK and dosimetry findings from the single-administration study with early data from the repeat-dosing program. Reyobiq redistributed through the CSF within roughly 24 hours and cleared the lateral ventricle with a half-life of 1.7 hours, which the company reads as the drug leaving the ventricles quickly while remaining at high concentration elsewhere in the fluid. Bulk RNA sequencing showed induction of cell-death genes around five hours after dosing, with peak activity at 24 hours. In ReSPECT-LMM, the repeated-dosing trial, Cohort 1a cleared without dose-limiting toxicities and further cohorts are enrolling. The release gives no patient counts for either study and no response figures.
CNSide's cost-of-care math
Kelly Kreitzburg Ondrasek, Ph.D., a medical science liaison at CNSide Diagnostics, presented "Economic Impact of Earlier Detection and Therapeutic Management of Leptomeningeal Metastases Using CNSide: A Cost-of-Care Analysis," an update of a health-economics model the company has shown before. The model put average LM-related treatment costs at approximately $119,550 a month, or about $717,300 over six months, and estimated that a pathway built on earlier definitive diagnosis, targeted treatment and quantitative monitoring would cut monthly costs by 33% to 47%. The release does not describe the cost inputs, the comparator pathway or any patient-level validation.
What Cerenome is
Plus Therapeutics announced July 31 that it would become Cerenome, Inc. and move its Nasdaq listing from PSTV to CNSY on Aug. 3. It describes three pieces. CNSide is a commercially available and reimbursed CSF-based platform for cellular and multiomic characterization of cerebrospinal fluid in patients with or at risk for CNS cancers. Reyobiq is an investigational targeted radiotherapeutic in trials for leptomeningeal metastases, recurrent glioblastoma and pediatric brain cancer. A data and AI platform built with Ephemeral Technologies rounds it out. An earlier release reports an in-network agreement with Health Care Service Corporation covering more than 150 million lives for CNSide.
"The REYOBIQ findings provide additional support for broad CSF distribution, limited systemic exposure in most patients, and the continued evaluation of repeat dosing," said Marc H. Hedrick, M.D., president and chief executive officer. "The CNSide analysis reinforces the potential economic value of earlier, information-rich disease management." The company said both posters would be posted on its publications page after the meeting.
Why This Matters to the APO|APE Reader
CNSide is one of the few commercial CSF assays positioned to replace repeat cytology in suspected leptomeningeal disease, and Cerenome's pitch now rests on a diagnostic that feeds patients into its own radiotherapeutic trials, which makes the 33% to 47% cost model an argument to payers as much as to neuro-oncologists. A 1.7-hour ventricular half-life also settles a practical question for anyone administering intrathecal radiopharmaceuticals, since dosimetry for the ventricular lining depends on how long activity sits there. The number missing from both posters is the same: how many patients these conclusions were drawn from.
