Biocept has signed a non-exclusive licencing agreement with Plus Therapeutics for its cerebrospinal fluid (CSF)-based tumour cell capture and enumeration platform, CNSide.

The non-exclusive licence agreement expands the previous laboratory services agreement between the two companies, signed in June last year.

Under the terms of the agreement, Plus will obtain a non-exclusive licence to Biocept’s CNSide assay to evaluate its investigational therapy for leptomeningeal metastases (LM).

In exchange, the US drugmaker will pay Biocept $150,000, by issuing shares in its common stock, and can exclusively licence the assay by making a $1m payment.

The molecular diagnostics company will offer its expertise, including consulting on equipment and materials sourcing, along with the necessary technology and training to perform CNSide.

Plus will pay $6,000 per CSF tumour cell enumeration analysis performed in Biocept’s CLIA-certified and CAP-accredited laboratory, until the technology transfer is completed.

Upon completion of the technology transfer, the US drugmaker will pay Biocept $300,000, along with fees on a sliding scale, starting at $2,800 for each CNSide test performed.

Biocept president and CEO Antonino Morales said: “We view this agreement as further validation of the clinical utility of CNSide and the important role it plays in diagnosing and monitoring patients with LM.

“It also sets the stage for future agreements with other companies developing treatments for cancer of the CNS and provides Biocept with non-dilutive funding to support our goal of establishing CNSide as the standard of care under the National Comprehensive Cancer Network (NCCN) guidelines.

“Importantly, Plus will reimburse Biocept for CNSide testing performed prior to completion of the technology transfer at $6,000 per enumeration. This amount more than covers our costs and potentially sets the stage for reimbursement at a similar level in future arrangements.”

CNSide is a tumour cell capture and enumeration platform, designed to detect, characterise, and quantify tumour cells in CSF of patients with different cancers, and suspected LM.

It also provides a sensitive and specific quantitative method to evaluate tumour status and response to treatment compared to conventional CSF cytology or imaging monitoring.

Plus will use the CNSide assay in its ReSPECT-LM Phase 1/2a dose-escalation clinical trial to evaluate its targeted radiotherapeutic, Rhenium 186 Obisbemeda, in patients with LM.

The pharmaceutical company recently completed Phase 1/Part A of the ReSPECT-LM trial and announced positive preliminary safety and efficacy results.

It has secured the US Food and Drug Administration (FDA) approval to advance the ReSPECT-LM clinical trial to Phase 1/Part B.

Plus Therapeutics president and CEO Marc H Hedrick said: “The CNSide test is the emerging gold standard for the definitive diagnosis and follow-up of patients with LM.

“The CNSide technology may, in the near future, supplement or replace existing diagnostic technology for cerebrospinal fluid malignancies.

“We view CNSide as an important complement to our novel radiotherapeutic technology, Rhenium 186 Obisbemeda, now in clinical development for leptomeningeal metastases in our actively enrolling ReSPECT-LM trial.”