Assessment of the Mechanisms of Action of Eribulin in Patients with Advanced Liposarcoma Through the Evaluation of Radiological, Functional, and Tissue Responses: A Prospective Monocentric Study (Malibu Study)

<b>Background:</b> Liposarcoma (LPS) is one of the most frequent histotypes of soft tissue sarcoma (STS). Eribulin is a cytotoxic agent that has improved overall survival in patients with advanced LPS. Additionally, preclinical and clinical evidence suggests its influence on vascularization and cellular differentiation. Based on these data, we developed this study to investigate non-mitotic effects of eribulin in patients with advanced LPS. <b>Methods:</b> In this prospective monocentric observational study, we included patients with advanced LPS eligible to receive eribulin. An assessment with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and a biopsy were planned before treatment and after four cycles of eribulin. DCE-MRI scans were elaborated to obtain perfusion and permeability maps. <b>Results:</b> From September 2019 to January 2024, 11 patients were enrolled. Among them, 8/11 (73%) had successful pre- and post-treatment assessment. At the time of the analysis, 8/11 (73%) patients had disease progression and 4 (36%) had died, median progression-free survival (mPFS) was 3.3 months, and median overall survival (mOS) was 8.7 months. Among the evaluable patients, DCE-MRI perfusion decreased after eribulin treatment in patients with disease control (partial response or stable disease), while perfusion values increased in patients with progressive disease (PD). No significant change in permeability was found. Post-treatment histological changes were seen nearly in all patients, with decreased cellularity the most common change (50%), followed by vascularization modifications (20%). <b>Conclusions:</b> Eribulin appears to exhibit non-mitotic activity involving both vascularization and cell differentiation in LPS patients. Further studies are needed to better define these effects.