Past, present and future of prognostic scores in follicular lymphoma

Genomic landscape of follicular lymphoma across a wide spectrum of clinical behaviors

While some follicular lymphoma (FL) patients do not require treatment or experience prolonged responses, others relapse early, and little is known about genetic alterations specific to patients with a particular clinical behavior. We selected 56 grade 1-3A FL patients according to their need of treatment or timing of relapse: never treated (n = 7), non-relapsed (19), late relapse (14), early relapse or POD24 (11), and primary refractory (5). We analyzed 56 diagnostic and 12 paired relapse lymphoid tissue biopsies and performed copy number alteration (CNA) analysis and next generation sequencing (NGS). We identified six focal driver losses (1p36.32, 6p21.32, 6q14.1, 6q23.3, 9p21.3, 10q23.33) and 1p36.33 copy-neutral loss of heterozygosity (CN-LOH). By integrating CNA and NGS results, the most frequently altered genes/regions were KMT2D (79%), CREBBP (67%), TNFRSF14 (46%) and BCL2 (40%). Although we found that mutations in PIM1, FOXO1 and TMEM30A were associated with an adverse clinical behavior, definitive conclusions cannot be drawn, due to the small sample size. We identified common precursor cells harboring early oncogenic alterations of the KMT2D, CREBBP, TNFRSF14 and EP300 genes and 16p13.3-p13.2 CN-LOH. Finally, we established the functional consequences of mutations by means of protein modeling (CD79B, PLCG2, PIM1, MCL1 and IRF8). These data expand the knowledge on the genomics behind the heterogeneous FL population and, upon replication in larger cohorts, could contribute to risk stratification and the development of targeted therapies.

Epigenetic targets in B- and T-cell lymphomas: latest developments

Non-Hodgkin's lymphomas (NHLs) comprise a diverse group of diseases, either of mature B-cell or of T-cell derivation, characterized by heterogeneous molecular features and clinical manifestations. While most of the patients are responsive to standard chemotherapy, immunotherapy, radiation and/or stem cell transplantation, relapsed and/or refractory cases still have a dismal outcome. Deep sequencing analysis have pointed out that epigenetic dysregulations, including mutations in epigenetic enzymes, such as chromatin modifiers and DNA methyltransferases (DNMTs), are prevalent in both B- cell and T-cell lymphomas. Accordingly, over the past decade, a large number of epigenetic-modifying agents have been developed and introduced into the clinical management of these entities, and a few specific inhibitors have already been approved for clinical use. Here we summarize the main epigenetic alterations described in B- and T-NHL, that further supported the clinical development of a selected set of epidrugs in determined diseases, including inhibitors of DNMTs, histone deacetylases (HDACs), and extra-terminal domain proteins (bromodomain and extra-terminal motif; BETs). Finally, we highlight the most promising future directions of research in this area, explaining how bioinformatics approaches can help to identify new epigenetic targets in B- and T-cell lymphoid neoplasms.

Relationship between BCL2 mutations and follicular lymphoma outcome in the chemoimmunotherapy era

How to identify follicular lymphoma (FL) patients with low disease burden but high risk for early progression is unclear. Building on a prior study demonstrating the early transformation of FLs with high variant allele frequency (VAF) BCL2 mutations at activation-induced cytidine deaminase (AICDA) sites, we examined 11 AICDA mutational targets, including BCL2, BCL6, PAX5, PIM1, RHOH, SOCS, and MYC, in 199 newly diagnosed grade 1 and 2 FLs. BCL2 mutations with VAF ≥20% occurred in 52% of cases. Among 97 FL patients who did not initially receive rituximab-containing therapy, nonsynonymous BCL2 mutations at VAF ≥20% were associated with increased transformation risk (HR 3.01, 95% CI 1.04-8.78, p = 0.043) and a trend toward shorter event-free survival (EFS, median 20 months with mutations versus 54 months without, p = 0.052). Other sequenced genes were less frequently mutated and did not increase the prognostic value of the panel. Across the entire population, nonsynonymous BCL2 mutations at VAF ≥20% were associated with decreased EFS (HR 1.55, 95% CI 1.02-2.35, p = 0.043 after correction for FLIPI and treatment) and decreased overall survival after median 14-year follow-up (HR 1.82, 95% CI 1.05-3.17, p = 0.034). Thus, high VAF nonsynonymous BCL2 mutations remain prognostic even in the chemoimmunotherapy era.

Prognostic value of interim 18F-FDG PET/CT in adult follicular lymphoma treated with R-CHOP

PURPOSE

The prognostic value of interim ¹⁸F-FDG PET/CT (I-PET) for follicular lymphoma (FL) is controversial, and may be related to the lack of strict standards in terms of age, chemotherapy regimen, and evaluation criteria in previous studies. This study aimed to investigate the prognostic value of I-PET in adult FL patients treated with R-CHOP.

METHODS

I-PET was performed in 30 adult FL patients after treatment with 3-5 cycles of R-CHOP. PET/CT images were assessed using the Deauville 5-point scale (D-5PS) criteria. Baseline PET/CT (B-PET) was performed in 24 of the patients with FL before treatment. The PET/CT image parameters, such as the SUVmax, TLG, and tMTV, were recorded. The prognostic values of sex, age, grade, Ann Arbor stage, LDH level, and I-PET were evaluated.

RESULTS

Kaplan-Meier analysis and Cox regression showed that sex, age, grade, Ann Arbor stage, LDH, and I-PET using the D-5PS criteria could not predict the PFS of adult patients with FL treated with R-CHOP (P>0.05). ROC curve analysis evaluated the predictive values of SUVmax, TLG, and tMTV in B-PET and I-PET and showed that none of them was predictive of PFS in adult FL patients (P>0.05). However, the variation in SUVmax (∆SUVmax) was predictive of PFS in adult FL patients (AUC=0.83, P=0.040), and the cutoff threshold was 4.85.

CONCLUSIONS

I-PET using the D-5PS criteria cannot predict the PFS of adult FL patients treated with R-CHOP. However, the ∆SUVmax between B-PET and I-PET is applicable for the prognosis of adult patients with FL.

Managing Follicular Lymphoma in the Elderly Population

Follicular lymphoma (FL) is one of the most commonly diagnosed types of indolent non-Hodgkin lymphoma (NHL). The median age of diagnosis for FL is 65 years old. Although the median life expectancy after diagnosis is approximately 10 years, the incurable disease has a high risk of transformation. This case report focuses on an 80-year-old patient diagnosed with low-grade follicular lymphoma which subsequently transformed leading to the patient's eventual demise as the patient took on the palliative intent. This case report aims to highlight the importance of clinical markers or prognostic factors to identify patients, specifically the elderly population who are at risk of transformation to aggressive forms when their FL remains at stage I-II phases. Currently, elderly patients with FL tend to be quickly dismissed with curative intent with chemotherapy, given their age and comorbidities, despite forming the majority of the population with follicular lymphoma. Age more than 60 years old has been shown to be one of the most powerful yet poor prognostic features in follicular lymphoma international prognostic index (FLIPI)-the main scoring system used for FL. Hence, further studies are required to look into the tailoring treatment for elderly patients with follicular lymphoma after risk stratifying them with appropriate clinical and prognostic markers.

Flow cytometry to detect bone marrow involvement by follicular lymphoma

BACKGROUND

High-quality data on bone marrow involvement (BMI) assessed by flow cytometry (FC) in follicular lymphoma (FL) is lacking.

AIMS

We set up a prospective protocol with a 10-color tube and acquisition of 500.000 leukocytes on a Nav flow cytometer for evaluation of BMI in FL by FC.

MATERIALS AND METHODS

FC was compared with a combination of histopathology and IGH gene rearrangement, which were considered the gold standard. We also compared BMI by FC with PET.

RESULTS

Fifty-two patients were included (median 67 years, 54% female). BMI by FC was seen in 35 (67%), with a median involvement of 1.2% (interquartile range: 0.3%-7%) of leukocytes. Comparison with the gold standard revealed two false negatives and two false positives (potentially true involvement undetected by the gold standard). BMI by PET was seen in 14/46 (30%). Immunophenotype of FL in the bone marrow was highly heterogeneous. The most common phenotypic abnormality was dim expression of CD19 (>0.5 log loss in 30% of patients). CD10 was negative in 13 (37%) and incompletely positive (overlap with the negative population) in a further 8 (28%) while entirely positive only in 14 (48%). Other abnormalities (loss of CD20, gain or loss of CD79b, expression of CD43, and substantial loss of CD45) were rare. Computational analysis by means of FlowSOM confirmed the heterogeneous phenotype, with FL from different patients clustering in unrelated metaclusters.

CONCLUSION

BMI by FL was frequent and immunophenotype was heterogeneous. However, this protocol enabled detection of FL in bone marrow in the vast majority of patients with bone marrow involvement by the gold standard.

Axicabtagene ciloleucel for the treatment of relapsed or refractory follicular lymphoma

INTRODUCTION

Axicabtagene ciloleucel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy that was recently approved for relapsed or refractory follicular lymphoma following progression on two or more lines of therapy including an anti-CD20 monoclonal antibody with an alkylating agent, providing a therapeutic breakthrough in a subset of indolent non-Hodgkin lymphoma associated with poor clinical outcomes.

AREAS COVERED

In this article, we outline the drug profile of axicabtagene ciloleucel in comparison to currently approved agents and other CAR T-cell and T-cell redirecting therapies under investigation for the treatment of relapsed or refractory follicular lymphoma. We also review the efficacy, safety and pharmacokinetic data from the ZUMA-5 phase II trial, which forms the basis of the recent approval of axicabtagene ciloleucel.

EXPERT OPINION

Axicabtagene ciloleucel is the first cellular therapy approved for relapsed or refractory follicular lymphoma, demonstrating high rates of durable responses and a manageable toxicity profile in heavily pre-treated patients.

The Prognostic Nutritional Index (PNI) is an independent predictor of overall survival in older patients with follicular lymphoma

The Prognostic Nutritional Index (PNI), a parameter combining serum albumin concentration and absolute lymphocyte count, is considered a measure of the nutritional and inflammatory status and the host's anti-tumor response. We analyzed the clinical characteristics and outcomes according to the PNI of 351 grades 1-3 A FL patients. Forty-one patients (12%) had a PNI ≤45, who were older and showed adverse baseline features. A low PNI was associated with a shorter PFS (only for patients >60 years), and OS (for all patients, 10-year OS, 52% versus 74%, p = 0.0001). The prognostic impact of the PNI on OS was confirmed in a multivariate model for patients >60 years (HR = 3, p = 0.006). In conclusion, the PNI is a readily accessible piece of information that can identify a small subset of FL patients with shorter survival, and it could be an aid to improve the nutritional status of patients prior to treatment initiation.

First external validation of the FLIPI-L score in a single-center series of patients with follicular lymphoma

The FLIPI-L has recently been proposed as a novel prognostic index in follicular lymphoma (FL), combining FLIPI and the presence of lymphopenia. In our single-center validation in 381 FL patients, lymphopenia was less frequent than in the original publication and thus the distribution of risk categories was different. Although it was not able to properly predict time to first treatment, FLIPI-L performed slightly better than FLIPI alone in the prediction of response, early relapse, progression-free and overall survival, and histological transformation. This new tool or others encompassing parameters from the microenvironment might improve upon the prognostic ability of classical scores.

Prognostic ability of five clinical risk scores in follicular lymphoma: A single-center evaluation

With the intention of identifying follicular lymphoma (FL) patients at higher risk of progression, early relapse (POD24), histological transformation (HT) or death, multiple risk scores (RS) have been proposed. However, it has not yet been established whether any of them globally outperforms the others. We evaluated the clinical utility and statistical performance of the five most widely used clinical scores (IPI, ILI, FLIPI, FLIPI2, PRIMA-PI) in a single-center series of 414 grade 1-3A FL patients diagnosed in the rituximab era. Overall concordance (proportion of patients allocated to the same risk category by all five RS) was 24%. FLIPI and FLIPI2 were predictive of time to first treatment. All five scores were predictive of response, POD24, progression-free, and OS, while only FLIPI predicted HT. IPI identified a small subset (7%) of truly high-risk patients (10-year OS of 16%). In subgroup analyses, we showed that ILI is useful in the prognostication of limited-disease patients, and PRIMA-PI is an age-independent score that can identify a high-risk subset of older patients. Performance metrics were slightly better for IPI in terms of calibration (Harrell's c-index 0.73), without major differences among RS regarding other parameters. Although the incorporation of molecular and imaging data will continue to refine the stratification of FL patients, FLIPI remains the most powerful clinical prognostic index in the rituximab era, predicting the greatest number of endpoints.