Should We Use Prognostic Indices and/or Biomarkers to Guide Therapy in Follicular Lymphoma? (SOHO 2023)
Integration of the mutation status of 7 genes with FLIPI and performance status is the basis of the clinic-genetic tool, m7- FLIPI, established in patients with advanced stage FL treated with induction rituximab-chemotherapy, predicts for both PFS and OS.8 A 23 gene-expression classifier, like m7-FLIPI, stratifies patients into low and high risk groups, predicting PFS but not OS.9 Interestingly, the validity of these biological-based tools is impacted by the chemotherapy backbone, particularly bendamustine.10 Other biological-based prognostic tools illustrate that certain features of the microenvironment are associated with higher risk of early disease progression following initial therapy including low PDL2 expression as a surrogate for an immune cold microenvironment and lack of intra-follicular CD4 expression.11,12 Imaging Prognostic Markers Baseline positron emission tomography (PET)-based biomarkers such as maximum standardised uptake value (SUVmax) and total metabolic tumour volume (TMTV) are also emerging as predictors of clinical outcomes.13–15 Two retrospective series identified high baseline SUVmax to be associated with inferior clinical outcomes...Predictive Biomarkers There are limited approved predictive biomarkers in FL, with EZH2 mutation status the only validated predictive biomarker to date based on the study showing higher response rates of EZH2- mutated FL patients to the EZH2 inhibitor tazemetostat compared to non-mutated.22 Notably, retrospective studies suggest that baseline EZH2 mutation status or high SUVmax might be linked to differential efficacy of chemotherapy backbones used at induction, providing the tantalizing possibility that a predictive biomarker might inform choice of therapy upfront.13,23,24 Given the growing armamentarium of therapies in the second, third line and beyond space, there is a crying need for predictive biomarkers to guide how we select and sequence therapies for patients...However, we may be at the precipice of change with the emergent biological and imaging-based modalities currently being evaluated alongside clinical studies. In the future, the opportunities where prognostic and/or predictive tools might best serve FL patients include: 1) Using prognostic tools at diagnoses to identify high-risk patients and pairing these patients to highly effective therapies based on predictive biomarkers; 2) Prognostic tools at the interim or end of induction treatment that could guide de-escalation or escalation of therapy and; 3) At relapse junctures, performing a suite of predictive biomarker assessments to allow selection of patients better served by specific therapies.