EHA 2021 | NGS screening for novel MRD tracking markers in the FOLL12 trial
Simone Ferrero, MD, University of Torino, Torino, Italy, discusses the findings of next-generation sequencing (NGS) analysis in the FOLL12 trial (NCT02063685), investigating the efficacy of response-adapted strategy in patients with follicular lymphoma. The study employed NGS to screen 120 patients with follicular lymphoma who failed BCL-2/IGH marker identification by standardized EuroMRD PCR, with the goal of identifying new markers for measurable residual disease (MRD) tracking during the follow-up portion of the study. 111/120 samples were successfully screened by NGS and a clonotype was identified in 56% of these samples. Dr Ferrero gives an overview of these findings. This interview took place at the virtual European Hematology Association (EHA) Congress 2021.
Transcript (edited for clarity)
This work is about follicular lymphoma. We screen a large population of follicular lymphoma patients enrolled in the Fondazione Italiana Linfomi FOLL12 trial, to find new molecular markers for MRD detection. Usually, follicular lymphoma is monitored for minimal residual disease by using the BCL-2/IgH rearrangement. With conventional PCR, NESA PCR or real-time PCR. By these classical methods, only about 50 to 60% of patients will be monitored because the primers, the use of primers are able to target only one of the rearrangements, the NBR rearrangements...
This work is about follicular lymphoma. We screen a large population of follicular lymphoma patients enrolled in the Fondazione Italiana Linfomi FOLL12 trial, to find new molecular markers for MRD detection. Usually, follicular lymphoma is monitored for minimal residual disease by using the BCL-2/IgH rearrangement. With conventional PCR, NESA PCR or real-time PCR. By these classical methods, only about 50 to 60% of patients will be monitored because the primers, the use of primers are able to target only one of the rearrangements, the NBR rearrangements.
So, in this trial, we enrolled about 800 patients and about 40% of these patients cannot be followed for MRD with conventional PCR. Therefore, we analyze the bone marrow aspirates of these patients without a molecular marker with two different NGS approach, approaches. The first is targeting immunoglobulin heavy chain rearrangement, and we use EuroClonality-NGS published approach using FR2 primers.
We screened 120 patients without the molecular marker, and we were able with this new approach to find a molecular marker, based on immunoglobulin on 56% of patients, 63 out of 111 evaluable patients. Then we used an alternative meter based on TLA, targeted local simplification. It is another NGS technique targeting, not the immunoglobulin rearrangement, but the BCL-2 immunoglobulin rearrangements. We used another technique that we recently published. We tested an initial series of 15 patients without a molecular marker, and we were able to identify a new BCL-2 consultation in eight out of 15, so about 50% of the patients. And what is most interesting is that the two used techniques are not exclusive. So, we were able to identify IgH rearrangements also in patients in which DNA failed and vice versa.
Then we started to use these new arrangements to follow MRD. As a proof of principle, we were able to design patient-specific primers on these new rearrangements. And we were able to do that, but MRD assay, real-time, PCR, MRD assay with high sensitivity. So, this is then, in these also it is presented only the first step, this marker screening approach. The second step will be to follow with MRD by NGS. Also, to follow the MRD and the follow-up samples of these patients to see whether it is possible to obtain and to use available and feasible new molecular markers for MRD detection in follicular lymphoma without a classical MRD mark.
Read more...
