This study will evaluate IgNGS at different time points in newly diagnosed DLBCL patients homogeneously treated (RCHOP) to address its correlation with conventional techniques (i.e., positron emission tomography/computed tomography imaging (PET/CT) and outcome.
In B-cell malignancies, every lymphocyte clone expresses a unique antigen receptor structure, therefore immunoglobulin gene rearrangements (the sequence of nucleotides at the V(D)J recombination site) serves as a specific marker for each clone. Methods of analysis have changed over time to improve the sensitivity and to allow its application in clinical settings. Diffuse Large B-cell lymphoma (DLBCL) displays molecular heterogeneity. In this context, IgNGS allows for detection of tumor clonotype from plasma (ctDNA) (Liquid Biopsy-LB) of DLBCL patients with high sensitivity and specificity. ctDNA can be tracked with this methodology in the vast majority (\>90%) of patients, in contrast to NGS-methods based on genotyping for specific DLBCL mutations, which have overall low frequency. Furthermore, most newly discovered neoantigens in lymphoma derive from immunoglobulin variable sequences, supporting the relevance of the analysis of this particular region in contrast to the use of specific B-cell mutations. Importantly, preliminary studies on clonotype detection by IgNGS at the end of treatment correlate with outcome (poorer progression-free survival) and the persistence or reemergence of the tumor clonotype by ctDNA studies may anticipate the clinical relapse. We propose to evaluate IgNGS at different time points in newly diagnosed DLBCL patients treated with RCHOP to address its correlation with conventional techniques (i.e., PET/CT imaging) and outcome.
Study Type
OBSERVATIONAL
Enrollment
30
3 longitudinal plasma samples will be evaluated at three different time points per patient: 0 (pre-treatment), end of treatment, and at 6 months after treatment.
Hospital de la Santa Creu i Sant Pau
Barcelona, Spain
Association between ctDNA level and clinical response at the end of treatment
Correlation between ctDNA level (in nanograms) and clinical response per PET/CT at the end of treatment (responses will be defined according to International Working Group consensus response evaluation criteria in lymphoma - IWGRECIL - 2017) will be assessed by means of Spearman correlation.
Time frame: 12-18 months
Correlation between detection of tumor clonotype ctDNA and relapse
The relationship between detection of tumor clonotype ctDNA (detection: yes/no, using a frequency threshold of 5%) and relapse (disease status will be assessed by PET/CT) will be measured by means of a logistic regression model. These analyses are explorative and will be done if possible.
Time frame: 18 months
Impact of IgNGS at the end of treatment and 6 months after treatment on outcome (as measured by progression-free survival PFS)
The relationship between impact of IgNGS (ctDNA level in nanograms, detection of tumor clonotype: yes/no, relative frequency of index sequences in %) with PFS will be assessed by means of a Proportional-hazards (PH) Cox regression model. These analyses are explorative and will be done if possible.
Time frame: 18 months
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