Multi-analyte liquid biopsies based treatment in advanced refractory cancers.

Abstract

e15623 Background: Tumor tissue profiling following invasive biopsies is presently the standard approach for indication-based therapy management in solid organ cancers. However, challenges in biopsy are traditionally described due to proximity to vital organs, or patients’ co-morbidities or unwillingness for an invasive procedure. Liquid biopsies for evaluation of cancers are also largely restricted to single gene testing for selection of targeted therapy agents. We developed a comprehensive liquid biopsy based multi-analyte (molecular and functional) investigation of the cancer (eLBx: Encyclopedic Liquid Biopsy) for selection and management of individualised treatments in a cohort of advanced refractory cancers. Methods: We obtained 20 mL blood from 65 patients with solid organ cancers where the disease had progressed following failure of at least two lines of systemic therapies and where biopsy to obtain tumor tissue for molecular profiling of tumor was unviable. Cell free tumor DNA (ctDNA) was interrogated for mutations, while exosomal mRNA was profiled for gene expression. Viable circulating tumor associated cells (C-TACs) were tested in vitro for chemoresistance and used to determine expression of cell surface signalling receptors by immunocytochemistry (ICC). The findings were integrated to generate patient-specific treatment regimens. In patients who received treatment, response was determined radiologically. Results: Fifty-one patients received eLBx-guided personalized treatments with combinations of cytotoxic, targeted and endocrine agents. No two patients received the same treatment regimen. Forty-three patients were evaluable for treatment response per protocol among whom Partial Response (PR) was observed in 14 patients yielding an Objective Response Rate (ORR) of 32.6%. Additionally, 23 patients showed Stable Disease thus yielding an overall Disease Control rate of 86.1%. Median Progression Free Survival (PFS) was 108 days. There were no Grade IV therapy related Adverse Events or therapy related deaths. Conclusions: The ability to make informed treatment choices from a convenient blood draw implies a reduced dependence on invasive biopsies for disease management. We demonstrate successful management of advanced refractory solid tumor malignancies using an integrational non-invasive multi-analyte liquid biopsy approach. Clinical trial information: CTRI/2019/02/017548.