Comprehensive tumor profiling-guided therapy in rare or refractory solid cancer: A feasibility study in daily clinical practice

Abstract

Tumor profiling has been shown to benefit patients with rare or refractory metastatic cancer, but several limitations hamper its use in daily clinical practice. We aim to assess the added benefit of a comprehensive tumor profiling, including factors predictive of response to targeted and cytotoxic therapy, in the treatment of refractory or rare solid tumors outside of a formal clinical trial. Patients were included between 2013 and 2017. Multiplatform comprehensive tumor profiling (CTP) was performed on FFPE specimens. Tumor response was evaluated by imaging using the RECIST criteria version 1.1. The PFS ratio was defined as PFS under CTP-guided therapy (PFS2)/PFS under previous standard therapy (PFS1). A clinical benefit was identified if the PFS ratio exceeded the 1.3 threshold value. In total, 184 patients were enrolled among whom 104 were evaluable for the PFS ratio. Objective response rates (ORR) were equal to 25% (CI95: 16.6-33.4%) and 36.5% (CI95: 27.2-45.8%) on the last therapy before CTP and on the CTP-guided therapy respectively (P-value=0.058 on paired proportion comparison test). The proportion of patients achieving a PFS2/PFS1 ratio≥1.3 was equal to 50%. The median PFS1 was statistically lower than PFS2 (120 days compared to 184 days respectively, P-value log rank 0.01). These results confirm the feasibility and the added benefit of a CTP in patients with refractory tumors in daily clinical practice especially in patients not able to enter a clinical trial.