Plus Therapeutics Releases Early-Cut Data From Cancer Studies For Brain Cancer Settings

Plus Therapeutics Inc PSTV reported interim updates from the ReSPECT-GBM and ReSPECT-LM studies of rhenium (186Re) obisbemeda, for recurrent glioblastoma (rGBM) and leptomeningeal metastases (LM).

The data were presented at the Society of Nuclear Medicine & Molecular Imaging Annual Meeting.

Data from 21 patients in the Phase 1 trial of 186RNL for GBM was presented to support the recommended Phase 2 trial dose for patients with tumor volumes ≤20 mL.

A single dose of rhenium (186Re) obisbemeda was generally safe and well-tolerated, with no dose-limiting toxicities and minimal systemic radiation exposure.

The data demonstrate efficacy signals in a prognostically unfavorable patient population.

The median overall survival (OS) in all 21 patients (including those receiving small radiation doses in early cohorts and five patients previously treated with Bevucizamab) was 11 months or a 38% increase in OS versus a median OS of approximately eight months for standard of care in rGBM.

Median OS in patients receiving >100 Gy of absorbed radiation dose was 76 weeks (17 months) versus 22 weeks (6 months) for those receiving <100 Gy (p=0.0002).

Interim results from 10 patients in the Phase 1 trial in Leptomeningeal Metastases show a single treatment with rhenium (186Re) obisbemeda decreased cerebrospinal fluid (CSF) tumor cell count and was well-tolerated.

Rhenium (186Re) obisbemeda doses administered through an intraventricular catheter (Ommaya reservoir) showed prompt, complete, and durable distribution throughout the CSF through Day 7.

A single rhenium (186Re) obisbemeda administered dose between 6.6 mCi and 26.4 mCi achieved absorbed doses of up to 88.98 Gy to the ventricles and cranial subarachnoid space.

No dose-limiting toxicities were observed, and safety observations were generally minor and resolved.

Phase 1/Part B, for continued dose escalation (Cohorts 4-7), will open following review by the U.S. Food and Drug Administration, and repeated dosing will be explored. An expansion in Cohort 3 is currently enrolling eligible patients.

Price Action: PSTV shares are up 1.59% at $2.56 on the last check Thursday.