Plus Therapeutics expands supply agreement with Biocept

Plus Therapeutics (PSTV) has expanded its supply agreement with Biocept (BIOC) by acquiring an option to exclusively license Biocept’s CNSide, a CSF-based tumor cell capture and enumeration platform, for patients receiving CNS radiotherapy. The option ensures that Plus Therapeutics has ongoing expanded access to the diagnostic CSF assay for patients with CNS cancers and can further develop and improve the assay specifically for patients with CNS cancers receiving radiotherapy. Under the terms of the agreement, CNSide developer, Biocept, has granted Plus Therapeutics a non-exclusive license to its CNSide cell enumeration assay for Plus’ investigational therapy for leptomeningeal metastases, rhenium obisbemeda, and an option for an exclusive license to the assay. In exchange, Plus Therapeutics will provide $150,000 of its common stock to Biocept. Prior to January 1, 2025, Plus Therapeutics will have the option for exclusivity for the field of radiotherapy in exchange for a $1.0 million payment, to be exercised at Plus Therapeutics’ discretion. CNSide is an assay based on proprietary quantitative tumor cell capture method paired with advanced digital imaging and molecular markers used to detect, characterize and quantify tumor cells in CSF of patients with a variety of solid organ carcinomas and suspected LM, particularly breast and lung cancer and melanoma which are leading causes of LM. CNSide provides a sensitive and specific quantitative method to evaluate tumor status and response to treatment compared to conventional CSF cytology or imaging monitoring. In March 2023, Biocept initiated enrollment in the FORESEE trial with CNSide. The FORESEE trial is a two-part, multicenter, prospective clinical trial expected to enroll up to 40 patients with breast or non-small cell lung cancer who have suspicious or confirmed LM. The goal of the FORESEE trial is to evaluate the performance of CNSide in monitoring LM’s response to treatment and to assess the impact of CNSide on treatment decisions made by physicians. The feasibility phase of the study is expected to complete in the first half of 2024, which will be followed by a validation phase that is estimated to include between 40 and 100 subjects.