XPO1 mutations identify early-stage CLL characterized by shorter time to first treatment and enhanced BCR signalling

Here we evaluated the epigenomic and transcriptomic profile of XPO1 mutant chronic lymphocytic leukaemia (CLL) and their clinical phenotype. By ATAC-seq, chromatin regions that were more accessible in XPO1 mutated CLL were enriched of binding sites for transcription factors regulated by pathways emanating from the B-cell receptor (BCR), including NF-κB signalling, p38-JNK and RAS-RAF-MEK-ERK. XPO1 mutant CLL, consistent with the chromatin accessibility changes, were enriched with transcriptomic features associated with BCR and cytokine signalling. By combining epigenomic and transcriptomic data, MIR155HG, the host gene of miR-155, and MYB, the transcription factor that positively regulates MIR155HG, were upregulated by RNA-seq and their promoters were more accessible by ATAC-seq. To evaluate the clinical impact of XPO1 mutations, we investigated a total of 957 early-stage CLL subdivided into 3 independent cohorts (N = 276, N = 286 and N = 395). Next-generation sequencing analysis identified XPO1 mutations as a novel predictor of shorter time to first treatment (TTFT) in all cohorts. Notably, XPO1 mutations maintained their prognostic value independent of the immunoglobulin heavy chain variable status and early-stage prognostic models. These data suggest that XPO1 mutations, conceivably through increased miR-155 levels, may enhance BCR signalling leading to higher proliferation and shorter TTFT in early-stage CLL.

Impact of Sars-CoV-2 Prophylaxis with Tixagevimab-Cilgavimab in High-Risk Patients with B-Cell Malignancies: A Single-Center Retrospective Study

Severe Acute Respiratory Syndrome CoronaVirus‐2 (SARS‐CoV‐2) infection can result in different clinical manifestations (COVID-19), starting from asymptomatic disease to life threatening respiratory insufficiency. Onco-haematologic patients are at higher risk to develop severe COVID-19. In particular, patients affected by lymphoproliferative diseases, given the impaired cell-mediated and antibody-mediated immunity and treatment toxicity, develop more often a symptomatic and a more serious disease of Covid-19. Various therapeutic and prophylactic agents are being used against COVID‐19 such as antiviral drugs, vaccines and antiviral S‐protein monoclonal antibodies. Pre-exposure prophylaxis with AZD442/Evusheld (tixagevimab-cilgavimab) may be a complementary strategy to decrease the incidence or severity of COVID-19 for patients with B-cell malignancies. Tixagevimab-cilgavimab is a combination of two monoclonal antibodies that bind SARS-CoV-2 spike protein and inhibits the attachment to the surface of cells, preventing viral entry in the cell and COVID-19 development. In the setting of hematology real-life, few data are available on the impact of pre-exposure prophylaxis, given the multiple factors involved in the clinical behavior of SARS-CoV-2 . Our aim was to evaluate the clinical benefit and the safety of this strategy at our center.

Additional lesions identified by genomic microarrays are associated with an inferior outcome in low-risk chronic lymphocytic leukaemia patients

We explored the relevance of genomic microarrays (GM) in the refinement of prognosis in newly diagnosed low-risk chronic lymphocytic leukaemia (CLL) patients as defined by isolated del(13q) or no lesions by a standard 4 probe fluorescence in situ hybridization (FISH) analysis. Compared to FISH, additional lesions were detected by GM in 27 of the 119 patients (22.7%). The concordance rate between FISH and GM was 87.4%. Discordant results between cytogenetic banding analysis (CBA) and GM were observed in 45/119 cases (37.8%) and were mainly due to the intrinsic characteristics of each technique. The presence of additional lesions by GM was associated with age > 65 years (p = 0.047), advanced Binet stage (p = 0.001), CLL-IPI score (p < 0.001), a complex karyotype (p = 0.004) and a worse time-to-first treatment in multivariate analysis (p = 0.009). Additional lesions by GM were also significantly associated with a worse time-to-first treatment in the subset of patients with wild-type TP53 and mutated IGHV (p = 0.025). In CLL patients with low-risk features, the presence of additional lesions identified by GM helps to identify a subset of patients with a worse outcome that could be proposed for a risk-adapted follow-up and for early treatment including targeted agents within clinical trials.

Impact of anti-SARS-CoV-2 monoclonal antibodies in the management of patients with lymphoma and COVID19: A retrospective study

COVID19 in patients affected by lymphoma represents an important challenge because of the higher mortality rate. Anti-SARS-CoV-2 monoclonal antibodies (anti-S MoAbs) appear promising in this setting. We report a monocentric retrospective study including 176 patients affected by lymphoma which developed SARS-CoV-2 infection since the start of COVID19 pandemic. Overall, mortality was 13.1%, with a decreasing trend between first waves to the last wave of pandemic (18.5% vs. 9.4%, p 0.076). Patients receiving anti-S MoAbs (41.3%) showed inferior mortality rate (overall survival, OS 93.2% vs. 82.7%, p 0.025) with no serious toxicity, reduced documented pneumonia (26% vs. 33%, p 0.005), and reduced need of oxygen support (14.5% vs. 35.7%, p 0.003). Among patients who received 3 doses of vaccine, the employment of anti-COVID MoAbs showed a trend of superior survival versus those who did not receive Anti-S MoAbs (OS rates 97.3% vs. 84.2%, p 0.064). On multivariate analysis, active haematological disease (OS 72% (HR 2.49 CI 1.00-6.41), bendamustine exposure (OS 60% HR 4.2 CI 1.69-10.45) and at least one comorbidity (HR 6.53 CI 1.88-22.60) were independent prognostic factors for death. Our study confirms the adverse prognostic role of COVID-19 in lymphoma patients in presence of active disease, comorbidities and previous exposure to bendamustine. In our experience, anti-S MoAbs represented a therapeutic option in vaccinated patients.

Role of Rituximab Addition to First-line Chemotherapy Regimens in Nodular Lymphocyte-predominant Hodgkin Lymphoma: A Study by Fondazione Italiana Linfomi

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare entity whose neoplastic cells retain a B-cell phenotype with expression of CD20. Radiotherapy is recommended for favorable stage IA disease while for other stages guidelines suggest therapeutic strategies similar to those used for classic HL. The role of rituximab, although quite widespread, is not completely elucidated. We retrospectively analyzed baseline characteristics of 308 consecutive patients with NLPHL diagnosed in 19 Italian centers from 2000 to 2018. With a median follow-up of 8.4 years (interquartile range: 4.5–12.4) for treated patients, median overall survival (OS) was not reached and estimated 5-year OS was 97.8% and 5-year progression-free survival (PFS) was 84.5%. Five-year cumulative incidence of histological transformation was 1.4%, 95% confidence interval (CI), 0.5%-3.8%. After adjusting for lymphocyte count, splenic involvement, bulky disease and B symptoms (fever, drenching night sweats, unintentional loss >10% of body weight within the preceding 6 months), patients with stage II or more showed superior PFS with immunochemotherapy in comparison to chemotherapy alone (hazard ratio = 0.4, 95% CI, 0.2-0.8; P = 0.015). Our data suggest an advantage of the use of rituximab combined with chemotherapy ± radiotherapy in the treatment of stage II–III–IV NLPHL.

Research Topic: Measurable Residual Disease in Hematologic Malignancies. Can digital droplet PCR improve measurable residual disease monitoring in chronic lymphoid malignancies?

Minimal/measurable residual disease (MRD) monitoring is progressively changing the management of hematologic malignancies. The possibility of detecting the persistence/reappearance of disease in patients in apparent clinical remission offers a refined risk stratification and a treatment decision making tool. Several molecular techniques are employed to monitor MRD, from conventional real-time quantitative polymerase chain reaction (RQ-PCR) to next generation sequencing and digital droplet PCR (ddPCR), in different tissues or compartments through the detection of fusion genes, immunoglobulin and T-cell receptor gene rearrangements or disease-specific mutations. RQ-PCR is still the gold standard for MRD analysis despite some limitations. ddPCR, considered the third-generation PCR, yields a direct, absolute, and accurate detection and quantification of low-abundance nucleic acids. In the setting of MRD monitoring it carries the major advantage of not requiring a reference standard curve built with the diagnostic sample dilution and of allowing to reduce the number of samples below the quantitative range. At present, the broad use of ddPCR to monitor MRD in the clinical practice is limited by the lack of international guidelines. Its application within clinical trials is nonetheless progressively growing both in acute lymphoblastic leukemia as well as in chronic lymphocytic leukemia and non-Hodgkin lymphomas. The aim of this review is to summarize the accumulating data on the use of ddPCR for MRD monitoring in chronic lymphoid malignancies and to highlight how this new technique is likely to enter into the clinical practice.

Sialylation regulates migration in chronic lymphocytic leukemia

Sialylation is the terminal addition of sialic acid to underlying glycans and plays a prominent role in cell adhesion and immune regulation. Sialylated structures found on adhesion molecules, such as CD49d, mediate the interactions between cancer cells and the microenvironment, facilitating metastatic seeding in target organs. Chronic lymphocytic leukemia (CLL) is a clonal B-cell malignancy characterized by the accumulation of CD5- positive B cells in the peripheral blood, bone marrow and lymph nodes. CLL cells proliferate mainly in the lymph node "proliferation centers", where the microenvironment provides pro-survival signals. Thus, migration and homing into these protective niches play a crucial role in CLL biology. In recent years, therapeutic strategies aiming at inducing the egress of CLL cells from the lymph nodes and bone marrow into the circulation have been highly successful. In this study, the sialylation status of 79 untreated and 24 ibrutinibtreated CLL patients was characterized by flow cytometry. Moreover, the effect of sialic acid removal on migration was tested by a transwell assay. Finally, we examined the sialylation status of CD49d by Western blot analysis. We found that CLL cells are highly sialylated, particularly those characterized by an "activated" immune phenotype. Notably, sialylation regulates CLL migration through the post-translational modification of CD49d. Finally, we showed that therapeutic agents that induce CLL mobilization from their protective niches such as ibrutinib, modulate the levels of sialic acids. We propose that sialylation is an important regulator of CLL trafficking and may represent a novel target to further improve CLL therapy.

Circulating cell-free DNA for target quantification in hematologic malignancies: Validation of a protocol to overcome pre-analytical biases

Circulating tumor DNA (ctDNA) has become the most investigated analyte in blood. It is shed from the tumor into the circulation and represents a subset of the total cell-free DNA (cfDNA) pool released into the peripheral blood. In order to define if ctDNA could represent a useful tool to monitor hematologic malignancies, we analyzed 81 plasma samples from patients affected by different diseases. The results showed that: (i) the comparison between two different extraction methods Qiagen (Hilden, Germany) and Promega (Madison, WI) showed no significant differences in cfDNA yield, though the first recovered higher amounts of larger DNA fragments; (ii) cfDNA concentrations showed a notable inter-patient variability and differed among diseases: acute lymphoblastic leukemia and chronic myeloid leukemia released higher amounts of cfDNA than chronic lymphocytic leukemia, and diffuse large B-cell lymphoma released higher cfDNA quantities than localized and advanced follicular lymphoma; (iii) focusing on the tumor fraction of cfDNA, the quantity of ctDNA released was insufficient for an adequate target quantification for minimal residual disease monitoring; (iv) an amplification system proved to be free of analytical biases and efficient in increasing ctDNA amounts at diagnosis and in follow-up samples as shown by droplet digital PCR target quantification. The protocol has been validated by quality control rounds involving external laboratories. To conclusively document the feasibility of a ctDNA-based monitoring of patients with hematologic malignancies, more post-treatment samples need to be evaluated. This will open new possibilities for ctDNA use in the clinical practice.

High rate of durable responses with undetectable minimal residual disease with frontline venetoclax and rituximab in young and fit patients with chronic lymphocytic leukemia and an adverse biologic profile: results of the GIMEMA phase II LLC1518 - 'Veritas' study

The GIMEMA phase II LLC1518 VERITAS trial investigated the efficacy and safety of frontline, fixed-duration venetoclax and rituximab (VenR) combination in young (≤65 years) and fit patients with chronic lymphocytic leukemia (CLL) and unmutated IGHV and/or TP53 disruption. Treatment consisted of the Ven ramp-up, six-monthly courses of the VenR combination, followed by six monthly courses of Ven single agent. A centralized assessment of measurable minimal residual disease (MRD) was performed on the peripheral blood (PB) and bone marrow (BM) by ASO-PCR at the end of treatment (EOT) and during the follow-up. The primary endpoint was the complete remission (CR) rate at the EOT. Seventy-five patients were enrolled; the median age was 54 years (range 38-65), 96% had unmutated IGHV, 9 (12%) had TP53 disruption, and 4% were IGHV mutated with TP53 disruption. The overall response rate (ORR) at the EOT was 94.7%, with a CR rate of 76%. An undetectable (u) MRD was recorded in 69.3% of patients in the PB and 58.7% in the BM. The 12-month MRD-free survival in the 52 patients with uMRD in the PB at the EOT was 73.1%. After a median follow-up of 20.8 months, no disease progressions were observed. Three patients have died, two due to Covid-19 and 1 to tumor lysis syndrome. The first report of the VERITAS study shows that frontline VenR was associated with a high rate of CRs and durable responses with uMRD in young patients with CLL and unfavorable genetic characteristics.

A Clinical Prognostic Model Based on Machine Learning from the Fondazione Italiana Linfomi (FIL) MCL0208 Phase III Trial

Simple Summary

The interest in using Machine-Learning (ML) techniques in clinical research is growing. We applied ML to build up a novel prognostic model from patients affected with Mantle Cell Lymphoma (MCL) enrolled in a phase III open-labeled, randomized clinical trial from the Fondazione Italiana Linfomi (FIL)—MCL0208. This is the first application of ML in a prospective clinical trial on MCL lymphoma. We applied a novel ML pipeline to a large cohort of patients for which several clinical variables have been collected at baseline, and assessed their prognostic value based on overall survival. We validated it on two independent data series provided by European MCL Network. Due to its flexibility, we believe that ML would be of tremendous help in the development of a novel MCL prognostic score aimed at re-defining risk stratification.

Abstract

Background: Multicenter clinical trials are producing growing amounts of clinical data. Machine Learning (ML) might facilitate the discovery of novel tools for prognostication and disease-stratification. Taking advantage of a systematic collection of multiple variables, we developed a model derived from data collected on 300 patients with mantle cell lymphoma (MCL) from the Fondazione Italiana Linfomi-MCL0208 phase III trial (NCT02354313). Methods: We developed a score with a clustering algorithm applied to clinical variables. The candidate score was correlated to overall survival (OS) and validated in two independent data series from the European MCL Network (NCT00209222, NCT00209209); Results: Three groups of patients were significantly discriminated: Low, Intermediate (Int), and High risk (High). Seven discriminants were identified by a feature reduction approach: albumin, Ki-67, lactate dehydrogenase, lymphocytes, platelets, bone marrow infiltration, and B-symptoms. Accordingly, patients in the Int and High groups had shorter OS rates than those in the Low and Int groups, respectively (Int→Low, HR: 3.1, 95% CI: 1.0–9.6; High→Int, HR: 2.3, 95% CI: 1.5–4.7). Based on the 7 markers, we defined the engineered MCL international prognostic index (eMIPI), which was validated and confirmed in two independent cohorts; Conclusions: We developed and validated a ML-based prognostic model for MCL. Even when currently limited to baseline predictors, our approach has high scalability potential.

Efficacy of Front-Line Ibrutinib and Rituximab Combination and the Impact of Treatment Discontinuation in Unfit Patients with Chronic Lymphocytic Leukemia: Results of the Gimema LLC1114 Study

Simple Summary

This prospective, multicenter study aimed to investigate the efficacy and safety of a front-line treatment with the ibrutinib and rituximab combination in 146 unfit patients with chronic lymphocytic leukemia (CLL). We observed an OR, CR, and 48-month PFS rates of 87%, 22.6%, and 77%, respectively. Responses with undetectable MRD were observed in 6.2% of all patients and 27% of CR patients. TP53 disruption and B-symptoms revealed a significant and independent impact on PFS. The 48-month cumulative treatment discontinuation rate due to adverse events in this patient population was 29.1%. It was significantly higher in male patients, in patients aged ≥70 years, and in those managed at centers that enrolled less than five patients. In conclusion, the ibrutinib and rituximab combination was an effective front-line treatment for unfit patients with CLL. However, a high rate of treatment discontinuations due to adverse events was observed in this unfit population.

Abstract

The GIMEMA group investigated the efficacy, safety, and rates of discontinuations of the ibrutinib and rituximab regimen in previously untreated and unfit patients with chronic lymphocytic leukemia (CLL). Treatment consisted of ibrutinib, 420 mg daily, and until disease progression, and rituximab (375 mg/sqm, given weekly on week 1–4 of month 1 and day 1 of months 2–6). This study included 146 patients with a median age of 73 years, with IGHV unmutated in 56.9% and TP53 disrupted in 22.2%. The OR, CR, and 48-month PFS rates were 87%, 22.6%, and 77%, respectively. Responses with undetectable MRD were observed in 6.2% of all patients and 27% of CR patients. TP53 disruption (HR 2.47; p = 0.03) and B-symptoms (HR 2.91; p = 0.02) showed a significant and independent impact on PFS. The 48-month cumulative rates of treatment discontinuations due to disease progression (DP) or adverse events (AEs) were 5.6% and 29.1%, respectively. AEs leading more frequently to treatment discontinuation were atrial fibrillation in 8% of patients, infections in 8%, and non-skin cancers in 6%. Discontinuation rates due to AEs were higher in male patients (HR: 0.46; p = 0.05), patients aged ≥70 years (HR 5.43, p = 0.0017), and were managed at centers that enrolled <5 patients (HR 5.1, p = 0.04). Patients who discontinued ibrutinib due to an AE showed a 24-month next treatment-free survival rate of 63%. In conclusion, ibrutinib and rituximab combination was an effective front-line treatment with sustained disease control in more than half of unfit patients with CLL. Careful monitoring is recommended to prevent and manage AEs in this patient population.

Does MRD have a role in the management of iNHL?

Among indolent non-Hodgkin lymphomas (iNHLs), the analysis of measurable/minimal residual disease (MRD) has been extensively applied to follicular lymphoma (FL). Treatment combinations have deeply changed over the years, as well as the techniques to measure MRD, which is currently evaluated only in the setting of clinical trials. Here, we discuss the evidence on the role of molecular monitoring in the management of FL. Mature data support the quantification of molecular tumor burden at diagnosis as a tool to stratify patients in risk categories and of MRD evaluation at the end of treatment to predict progression-free survival and overall survival. Moreover, MRD deserves further studies as a tool to refine the clinical/metabolic response and to modulate treatment intensity/duration. Patients with a higher relapse probability can be identified, but the relevance of continuous molecular follow-up should be clarified by kinetic models of MRD analysis. Being the BCL2/heavy chain immunoglobulin gene hybrid rearrangement detectable in about 50% to 60% of advanced FL and in 30% of positron emission tomography/computed tomography-staged localized FL, technical advancements such as next-generation sequencing/target locus amplification may allow broadening the FL population carrying a molecular marker. Droplet digital polymerase chain reaction can better quantify MRD at low levels, and novel sources of DNA, such as cell-free DNA, may represent a noninvasive tool to monitor MRD. Finally, MRD in other iNHLs, such as lymphoplasmacytic lymphoma/Waldenström macroglobulinemia and marginal zone lymphoma, is beginning to be explored.

Response-Adapted Postinduction Strategy in Patients With Advanced-Stage Follicular Lymphoma: The FOLL12 Study

PURPOSE

We compared 2 years of rituximab maintenance (RM) with a response-adapted postinduction approach in patients with follicular lymphoma who responded to induction immunochemotherapy.

METHODS

We randomly assigned treatment-naïve, advanced-stage, high-tumor burden follicular lymphoma patients to receive standard RM or a response-adapted postinduction approach on the basis of metabolic response and molecular assessment of minimal residual disease (MRD). The experimental arm used three types of postinduction therapies: for complete metabolic response (CMR) and MRD-negative patients, observation; for CMR and MRD-positive (end of induction or follow-up) patients, four doses of rituximab (one per week, maximum three courses) until MRD-negative; and for non-CMR patients, one dose of ibritumomab tiuxetan followed by standard RM. The study was designed as noninferiority trial with progression-free survival (PFS) as the primary end point.

RESULTS

Overall, 807 patients were randomly assigned. After a median follow-up of 53 months (range 1-92 months), patients in the standard arm had a significantly better PFS than those in the experimental arm (3-year PFS 86% v 72%; P < .001). The better PFS of the standard vs experimental arm was confirmed in all the study subgroups except non-CMR patients (n = 65; P = .274). The 3-year overall survival was 98% (95% CI, 96 to 99) and 97% (95% CI, 95 to 99) in the reference and experimental arms, respectively (P = .238).

CONCLUSION

A metabolic and molecular response-adapted therapy as assessed in the FOLL12 study was associated with significantly inferior PFS compared with 2-year RM. The better efficacy of standard RM was confirmed in the subgroup analysis and particularly for patients achieving both CMR and MRD-negative.

Treatment with ibrutinib does not induce a TP53 clonal evolution in chronic lymphocytic leukemia

Not available.

High Basal Maximal Standardized Uptake Value (SUVmax) in Follicular Lymphoma Identifies Patients with a Low Risk of Long-Term Relapse

BACKGROUND

Despite that the unfavorable prognostic role of a high Total Metabolic Tumor Volume (TMTV) in Follicular Lymphoma has been demonstrated, the role of SUV_max alone at baseline PET/CT could have a different prognostic role.

PATIENTS AND METHODS

We performed a retrospective observational monocentric cohort study. All patients affected by FL who underwent a basal PET/CT were included. Two subgroups were identified and compared in terms of PFS and OS: (A) Basal SUV_max ≤ 6; and (B) Basal SUV_max > 6.

RESULTS

Ninety-four patients were included, 34 in group A (36.2%) and 60 in group B (63.8%). The PFS at two years was comparable in the two groups (97%). The five-year PFS was 73.5% for group A and 95% for group B (p 0.005). The five-year PFS in the whole cohort was 87.5%. A clear advantage was confirmed in group A in the absence of other risk factors. Patients with SUV_max ≤ 6 and no risk factors showed a 5-year PFS of 73% against 83% for patients with SUV_max > 6 and at least two risk factors.

CONCLUSION

A high FDG uptake favorably correlated with PFS. A low basal SUV_max reflected a higher rate of late relapse requiring a prolonged follow-up. The basal SUV_max is an approachable parameter with prognostic implications.

TH2/TH1 Shift Under Ibrutinib Treatment in Chronic Lymphocytic Leukemia

Ibrutinib may revert the T-helper (Th)2 polarization observed in chronic lymphocytic leukemia (CLL) by targeting the IL-2-inducible kinase, that shows a significant homology with the Bruton tyrosine kinase. In the front-line GIMEMA LLC1114 trial (ibrutinib+rituximab for 6 months, followed by ibrutinib maintenance), we investigated the modulation of T-cell cytokine production in 208 peripheral blood paired samples from 71 CLL patients: 71 samples prior to treatment (Day 0, D0) and at day +14 (D14; n=50), at month +8 (M8; 30), +12 (M12; 25), +18 (M18; 22) and +24 (M24; 10) of treatment. We documented a progressive decrease of CD3+CD4+IL-4+ T cells (Th2), that was significant at M8 and at M12 (p=0.019, p=0.002), a relative increase in the CD3+CD4+IFNγ+ T cells (Th1) and a decrease of CD3+CD4+IL-17+ (Th17) cells that was maintained up to M18 (M8 vs D0 p=0.003, M12 vs D0 p=0.003, M18 vs D0 p=0.004) of ibrutinib treatment. The Th2/Th1 ratio significantly decreased already after 14 days of treatment and was maintained thereafter (D14 vs D0 p=0.037, M8 vs D0 p=0.001, M12 vs D0 p=0.005, M18 vs D0 p=0.002). The Th2/Th1 modulation over time was significant only among patients with unmutated IGHV. The Th2/Th1 ratio below a cut-off of 0.088 at M8 was associated with the achievement of a complete response (CR) (p=0.016). Ibrutinib may shape the CLL T-cell profile, limiting Th2 activation and inducing a shift in the Th2/Th1 ratio. The association between the Th2/Th1 ratio decrease and the CR achievement suggests the in vivo generation of a potential host anti-tumor immune activation induced by ibrutinib.

Comparison of ibrutinib and idelalisib plus rituximab in real-life relapsed/resistant chronic lymphocytic leukemia cases

OBJECTIVES

To compare the capacity of ibrutinib (IB) and idelalisib-rituximab (IDELA-R) of prolonging overall survival (OS) as in CLL patients, previously treated with chemotherapy only.

METHODS

A real-life cohort of 675 cases has been identified and investigated in the database of the groups participating in the study.

RESULTS

At an unadjusted univariate analysis, a significant death risk reduction was observed favoring IB (IDELA-R vs IB HR = 0.5, 95% CI = 0.36-0.71) although with some limitations due to the non-randomized and retrospective nature of the study and to the lower number of patients in the IDELA-R group (112 cases) related to the current prescribing practice. To overcome the potential problem of confounding by indication, we adjusted the association between the type of therapy and mortality for all variables significantly associated with OS at Cox univariate analysis. Furthermore, those variables, differently distributed between the two study groups, were introduced into the multivariate Cox model to improve the effectiveness of the analysis. By introducing all these variables into the multiple Cox regression model, we confirmed the protective effect of IB vs IDELA-R (HR = 0.67, 95% CI = 0.45-0.98, P = .04) independent of potential confounders.

CONCLUSIONS

Although our analysis presents some constraints, that is, the unavailability of additional potential confounders, and the retrospective nature of the study, this observation may be of help for the daily clinical practice, particularly in the absence of randomized trials comparing the two schedules.

Immunoglobulin kappa deleting element rearrangements are candidate targets for minimal residual disease evaluation in mantle cell lymphoma

Minimal residual disease (MRD) assessment is of high clinical relevance in patients with mantle cell lymphoma (MCL). In mature B-cell malignancies, the presence of somatic hypermutations (SHM) in Variable-Diversity-Joining Heavy chain (VDJH) rearrangements leads to frequent mismatches between primers, probes, and the target, thus impairing tumor cells quantification. Alternative targets, such as immunoglobulin kappa-deleting-element (IGK-Kde) rearrangements, might be suitable for MRD detection. We aimed at evaluating the applicability of IGK-Kde rearrangements for MRD quantification in MCL patients by real-time quantitative polymerase chain reaction (RQ-PCR)/digital-droplet-PCR (ddPCR). IGK screening was performed on bone marrow samples from two cohorts: the first from Turin (22 patients enrolled in the FIL-MCL0208 trial, NCT02354313) and the second from Rome (15 patients). IGK-Kde rearrangements were found in 76% (28/37) of cases, representing the sole molecular marker in 73% (8/11) of IGH-BCL1/IGH negative cases. MRD RQ-PCR monitoring was possible in 57% (16/28) of cases, showing a 100% concordance with the conventional targets. However, the frequent background amplification affected the sensitivity of the assay, that was lower in MCL compared to acute lymphoblastic leukemia and in line with multiple myeloma published results. ddPCR had a good concordance with RQ-PCR and it might help to identify false positive/negative results. From a clinical perspective, we suggest that IGK-Kde can be a candidate target for MRD monitoring and deserves a validation of its predictive value in prospective MCL series.

“Miro” Study, a FIL multicenter phase II trial combining local radiotherapy and MRD-driven immunotherapy in early-stage follicular lymphoma

e20073

Background: Early stage follicular lymphoma (FL) is usually managed with involved field radiotherapy (IFRT), allowing eradication of the disease in 40-50% of patients (pts). The aim of this multicenter phase II prospective study was to evaluate the role of minimal residual disease (MRD) in identifying pts unlikely to be cured by IFRT, for whom an immunotherapy-based consolidation could improve outcome. Methods: 110 pts with stage I/II FL were enrolled and treated with 24 Gy IFRT. Peripheral blood (PB) and bone marrow (BM) samples were centralized to the FIL (Federazione Italiani Linfomi) MRD Network of EuroMRD-certified laboratories. In BCL2/IGH+ pts at baseline, MRD was analyzed by nested PCR (NEST) and RQ-PCR (RQ) in BM and/or PB after IFRT and every 6 months over a 3-year period. Pts with positive MRD by both NEST and RQ in the BM and/or PB after IFRT or who became positive during the follow-up (FU) were treated with 8 weekly doses of the anti-CD20 MoAb ofatumumab (OFA). Primary objective: efficacy of immunotherapy in obtaining a negative MRD. Results: 49 of 106 pts were males. Median age was 55 y (29-83). 69% of pts had inguinal involvement. At baseline, 30% of pts had a BCL2/IGH rearrangement (30 MBR, 1 MBR and mcr, 1 mcr) in BM and/or PB; the concordance between compartments was 90%. All pts obtained a clinical response after IFRT, with persistence of BCL2/IGH+ cells in PB and/or BM in 60% of cases. MRD-positive pts, either after IFRT (n = 18) or in case of conversion to a positive signal during the FU (n = 7), received OFA, obtaining a conversion to MRD negativity, in 20/22 cases (91% - CI 65.1-97.1), significantly superior to the expected 50%. After a median FU of 25 months, all but 2 pts who achieved a negative MRD with OFA are still negative. A clinical relapse or progression was observed in 17 pts: 13 (18%) among the 73 “no marker” pts; 2 relapses (16%) were observed among the 12 MRD-negative pts after IFRT and 2 among the 25 treated with OFA (8%), 1 having achieved a MRD negativity and 1 not. No significant differences in PFS have so far been observed between the three groups. Conclusions: In early stage FL RT alone is often insufficient to eradicate the disease, inducing a negative MRD only in 40% of pts, long-lasting only in half of them. The primary objective of this study - MRD negativity after immunotherapy - was achieved. The strategy of an immunotherapy consolidation after IFRT in MRD-positive pts allowed to increase molecular responses. A longer FU and further studies will allow to define the impact of this MRD-driven strategy also on clinical outcome. Clinical trial information: EudraCT number: 2012-001676-11 .

Redefining the prognostic likelihood of chronic lymphocytic leukaemia patients with borderline percentage of immunoglobulin variable heavy chain region mutations

In chronic lymphocytic leukaemia (CLL), caution is warranted regarding the clinical implications of immunoglobulin variable heavy chain region (IGHV) rearrangements with a 'borderline' (BL) percentage of mutations (i.e. 97-97·9% IGHV identity). We analysed the IGHV mutational status in 759 untreated CLL patients (cohort 1). BL-CLL (n = 36, 5%) showed a time to first treatment (TFT) similar to that of M-CLL (n = 338) and significantly longer than that of UM-CLL (n = 385), despite the enrichment in subset #2 cases. In fact, CLLs belonging to subset #2 (n = 15/759, 2%) were significantly more frequent among BL-CLLs (n = 5/36, 14%), with a brief TFT. TFT of BL-CLL remained comparable to that of M-CLL also considering the 327 CLL patients evaluated at diagnosis. These findings were then validated in an independent cohort 2 of 759 newly diagnosed CLL patients (BL-CLL: n = 11, 1·4%) and in all newly diagnosed patients from cohorts 1 and 2 (n = 1 086, 84% stage A; BL-CLL: n = 47, 4·3%). BL-CLL at diagnosis showed a biological profile comparable to that of M-CLL with a low frequency of unfavourable prognostic markers, except for a significant enrichment in subset #2. Our data suggest that the prognosis of BL-CLL is good and similar to that of M-CLL, with the exception of subset #2 cases.

Biological and clinical implications of BIRC3 mutations in chronic lymphocytic leukemia

BIRC3 is a recurrently mutated gene in chronic lymphocytic leukemia (CLL) but the functional implications of BIRC3 mutations are largely unexplored. Furthermore, little is known about the prognostic impact of BIRC3 mutations in CLL cohorts homogeneously treated with first-line fludarabine, cyclophosphamide, and rituximab (FCR). By immunoblotting analysis, we showed that the non-canonical nuclear factor-κB pathway is active in BIRC3-mutated cell lines and in primary CLL samples, as documented by the stabilization of MAP3K14 and by the nuclear localization of p52. In addition, BIRC3-mutated primary CLL cells are less sensitive to flu-darabine. In order to confirm in patients that BIRC3 mutations confer resistance to fludarabine-based chemoimmunotherapy, a retrospective multicenter cohort of 287 untreated patients receiving first-line FCR was analyzed by targeted next-generation sequencing of 24 recurrently mutated genes in CLL. By univariate analysis adjusted for multiple comparisons BIRC3 mutations identify a poor prognostic subgroup of patients in whom FCR treatment fails (median progression-free survival: 2.2 years, P<0.001) similar to cases harboring TP53 mutations (median progression-free survival: 2.6 years, P<0.0001). BIRC3 mutations maintained an independent association with an increased risk of progression with a hazard ratio of 2.8 (95% confidence interval 1.4-5.6, P=0.004) in multivariate analysis adjusted for TP53 mutation, 17p deletion and IGHV mutation status. If validated, BIRC3 mutations may be used as a new molecular predictor to select high-risk patients for novel frontline therapeutic approaches.

Minimal Residual Disease in Chronic Lymphocytic Leukemia: A New Goal?

In chronic lymphocytic leukemia (CLL), there is a growing interest for minimal residual disease (MRD) monitoring, due to the availability of drug combinations capable of unprecedented complete clinical responses. The standardized and most commonly applied methods to assess MRD in CLL are based on flow cytometry (FCM) and, to a lesser extent, real-time quantitative PCR (RQ-PCR) with allele-specific oligonucleotide (ASO) primers of immunoglobulin heavy chain genes (IgH). Promising results are being obtained using droplet digital PCR (ddPCR) and next generation sequencing (NGS)-based approaches, with some advantages and a potential higher sensitivity compared to the standardized methodologies. Plasma cell-free DNA can also be explored as a more precise measure of residual disease from all different compartments, including the lymph nodes. From a clinical point of view, CLL MRD quantification has proven an independent prognostic marker of progression-free survival (PFS) and overall survival (OS) after chemoimmunotherapy as well as after allogeneic transplantation. In the era of mechanism-driven drugs, the paradigms of CLL treatment are being revolutionized, challenging the use of chemoimmunotherapy even in first-line. The continuous administration of ibrutinib single agent has led to prolonged PFS and OS in relapsed/refractory and treatment naïve CLL, including those with TP53 deletion/mutation or unmutated IGHV genes, though the clinical responses are rarely complete. More recently, chemo-free combinations of venetoclax+rituximab, venetoclax+obinutuzumab or ibrutinib+venetoclax have been shown capable of inducing undetectable MRD in the bone marrow, opening the way to protocols exploring a MRD-based duration of treatment, aiming at disease eradication. Thus, beside a durable disease control desirable particularly for older patients and/or for those with comorbidities, a MRD-negative complete remission is becoming a realistic prospect for CLL patients in an attempt to obtain a long-lasting eradication and possibly cure of the disease. Here we discuss the standardized and innovative technical approaches for MRD detection in CLL, the clinical impact of MRD monitoring in chemoimmunotherapy and chemo-free trials and the future clinical implications of MRD monitoring in CLL patients outside of clinical trials.

Minimal residual disease (MRD) in non‐Hodgkin lymphomas: Interlaboratory reproducibility on marrow samples with very low levels of disease within the FIL (Fondazione Italiana Linfomi) MRD Network

In 2009, the four laboratories of the Fondazione Italiana Linfomi (FIL) minimal residual disease (MRD) Network started a collaborative effort to harmonize and standardize their methodologies at the national level, performing quality control (QC) rounds for follicular lymphoma (FL) and mantle cell lymphoma (MCL) MRD assessment. In 16 QC rounds between 2010 and 2017, the four laboratories received 208 bone marrow (BM) samples (126 FL; 82 MCL); 187 were analyzed, according to the EuroMRD Consortium guidelines, by both nested (NEST) polymerase chain reaction (PCR) and real-time quantitative (RQ) PCR for BCL2/IGH MBR or IGHV rearrangements. Here, we aimed at analyzing the samples that challenged the interlaboratory reproducibility and data interpretation. Overall, 156/187 BM samples (83%) were concordantly classified as NEST+/RQ+ or NEST-/RQ- by all the four laboratories. The remaining 31 samples (17%) resulted alternatively positive and negative in the interlaboratory evaluations, independently of the method and the type of rearrangement, and were defined "borderline" (brd) samples: 12 proved NEST brd/RQ brd, 7 NEST-/RQ brd, 10 NEST brd/RQ positive not quantifiable (PNQ), and 2 NEST brd/RQ-. Results did not change even increasing the number of replicates/sample. In 6/31 brd samples, droplet digital PCR (ddPCR) was tested and showed no interlaboratory discordance. Despite the high interlaboratory reproducibility in the MRD analysis obtained and maintained by the QC round strategy, samples with the lowest MRD levels can still represent a challenge: 17% (31/187) of our samples showed discordant results in interlaboratory assessments, with 6.4% (12/187) remained brd even applying the two methods. Thus, although representing a minority, brd samples are still problematic, especially when a clinically oriented interpretation of MRD results is required. Alternative, novel methods such as ddPCR and next-generation sequencing have the potential to overcome the current limitations.

Unravelling the suboptimal response of TP53-mutated chronic lymphocytic leukaemia to ibrutinib

TP53-disrupted chronic lymphocytic leukaemia (CLL) patients show a suboptimal long-term response to ibrutinib. We hereby report that ibrutinib-induced in vitro apoptosis and proliferation inhibition were significantly lower in TP53-mutated (TP53-M) CLL cells compared to TP53 wild-type cells. Contrariwise, venetoclax effectively killed TP53-M cells. Gene expression profile analysis of TP53-M cells revealed a downmodulation of B-cell receptor (BCR)-related genes and an upmodulation of genes with anti-apoptotic/pro-survival activity, suggesting that the survival and proliferation of TP53-M cells are less dependent on the BCR pathway. These observations further support the use of drug combinations for the optimal management of TP53-M CLL patients.

Clinicopathological features and outcome of chronic lymphocytic leukaemia in Chinese patients

Chronic lymphocytic leukaemia (CLL) is uncommon in Chinese population and its biology, genetics and treatment outcome in Chinese patients have not been comprehensively investigated. In this study, we studied the clinicopathological features and outcome of 212 Chinese patients with newly diagnosed CLL in Hong Kong and Singapore. The median age at diagnosis was 64 years. The majority of patients presented with early-stage disease (Binet stage A, 56.1%). Del(13)(q14) was the most frequent abnormality (41.7%) detected by fluorescence in situ hybridization (FISH) analysis. Del(17p) and TP53 gene mutations were detected in 7.8% and 8.2% of patients, respectively. MYD88 mutations were found at a higher frequency (11.5%) than expected. CLL with unmutated variable region of the immunoglobulin heavy chain genes (IGHV) occurred in only 31.2% of cases, and was associated with advanced-stage disease (p <0.01) and adverse FISH abnormalities (p<0.01). With a median follow-up of 39 months, the median overall survival (OS) was 108 months. The presence of del(17p) or TP53 mutations was associated with a significantly shorter time to first treatment and an inferior OS (p <0.01). Unmutated IGHV was also associated with a significantly shorter time to treatment (p <0.01). Among patients who required treatment, the median OS and progression-free survival (PFS) were 107 and 23 months, respectively. The presence of del(17p) was associated with a significantly inferior OS and PFS (p <0.01). In summary, Chinese CLL patients had similar genetic aberrations at diagnosis compared with those of Western populations. FISH abnormalities are major factors affecting outcome.

Immunoglobulin gene rearrangements in Chinese and Italian patients with chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in the Western world, whereas in Asia the incidence is about 10 times lower. The basis for this ethnic and geographic variation is currently unknown. The aim of this study was to characterize IGHVDJ rearrangements and stereotype of the HCDR3 region in a series of 623 Chinese CLL, in order to identify possible differences in immunoglobulin gene usage and their potential pathogenetic implications. Chinese CLL were compared to 789 Italian CLL. Chinese patients showed a higher proportion of mutated IGHV and a more frequent usage of IGHV3-7, IGHV3-74, IGHV4-39 and IGHV4-59 genes. A significantly lower usage of IGHV1-69 and IGHV1-2 was documented, with comparable IGHV3-21 frequency (3% Chinese vs 3.8% Italian CLL). The proportion of known stereotyped receptors was significantly lower in Chinese (19.7%) than in Italian CLL (25.8%), despite a significantly higher frequency of subset #8 (p= 0.0001). Moreover, new paired clusters were identified among Chinese cases. Overall, these data support a potential different antigenic exposure between Eastern and Western CLL.

Comparative analysis between RQ-PCR and digital droplet PCR of BCL2/IGH gene rearrangement in the peripheral blood and bone marrow of early stage follicular lymphoma

BCL2/IGH rearrangements were analysed by polymerase chain reaction (PCR) at diagnosis in paired peripheral blood (PB) and bone marrow (BM) samples from 67 patients with stage I/II follicular lymphoma (FL). Real time quantitative PCR (RQ-PCR) and digital droplet PCR (ddPCR) were performed in cases with a major breakpoint region (MBR+) at diagnosis and after localized radiotherapy and rituximab administration in order to investigate the applicability of ddPCR. The overall ddPCR/RQ-PCR concordance was 81·9% (113/138 samples) and 97·5% in the 40/138 with quantifiable disease (RQ-PCR≥10^-5 ). At baseline, ddPCR allowed the recovery of a MBR+ marker in 8/18 (44·4%) samples that resulted MBR-negative/minor cluster region-negative/minor BCL2-negative by qualitative PCR. Moreover, the tumour burden at diagnosis significantly predicted progression-free survival (PSF) only when quantified by ddPCR. Paired PB and BM samples analysis demonstrated a high concordance in the detection of BCL2/IGH+ cells by qualitative and quantitative methods; in particular, 40/62 samples were positive by ddPCR (25 PB+/BM+; 9 PB+/BM-; 6 PB-/BM+), with 34/40 (85%) identified by the study of PB only. In conclusion, in localized FL, ddPCR is a promising tool for monitoring minimal residual disease (MRD) that is at least comparable to RQ-PCR and potentially more accurate. PB is a suitable source for serial BCL2/IGH MRD assessments, regardless of the methodology utilized.

Inter- and intra-patient clonal and subclonal heterogeneity of chronic lymphocytic leukaemia: evidences from circulating and lymph nodal compartments

Whole exome sequencing and copy number aberration (CNA) analysis were performed on cells taken from peripheral blood (PB) and lymph nodes (LN) of patients with chronic lymphocytic leukaemia (CLL). Of 64 non-silent somatic mutations, 54 (84·4%) were clonal in both compartments, 3 (4·7%) were PB-specific and 7 (10·9%) were LN-specific. Most of the LN- or PB-specific mutations were subclonal in the other corresponding compartment (variant frequency 0·5-5·3%). Of 41 CNAs, 27 (65·8%) were shared by both compartments and 7 (17·1%) were LN- or PB-specific. Overall, 6 of 9 cases (66·7%) showed genomic differences between the compartments. At subsequent relapse, Case 10, with 6 LN-specific lesions, and Case 100, with 6 LN-specific and 8 PB-specific lesions, showed, in the PB, the clonal expansion of LN-derived lesions with an adverse impact: SF3B1 mutation, BIRC3 deletion, del8(p23·3-p11·1), del9(p24·3-p13·1) and gain 2(p25·3-p14). CLL shows an intra-patient clonal heterogeneity according to the disease compartment, with both LN and PB-specific mutations/CNAs. The LN microenvironment might contribute to the clonal selection of unfavourable lesions, as LN-derived mutations/CNAs can appear in the PB at relapse.

Increased chronic lymphocytic leukemia proliferation upon IgM stimulation is sustained by the upregulation of miR-132 and miR-212

To assess the involvement of microRNAs (miRNAs) in B-cell receptor (BCR) stimulation, we first evaluated miRNA profiling following IgM cross-linking in chronic lymphocytic leukemia (CLL) cells and in normal B lymphocytes. Second, we combined miRNA and gene expression data to identify putative miRNA functional networks. miRNA profiling showed distinctive patterns of regulation after stimulation in leukemic versus normal B lymphocytes and identified a differential responsiveness to BCR engagement in CLL subgroups according to the immunoglobulin heavy chain variable region mutational status and clinical outcome. The most significantly modulated miRNAs in stimulated CLL are miR-132 and miR-212. Notably, these miRNAs appeared regulated in progressive but not in stable CLL. Accordingly, gene profiling showed a significant transcriptional response to stimulation exclusively in progressive CLL. Based on these findings, we combined miRNA and gene expression data to investigate miR-132 and miR-212 candidate interactions in this CLL subgroup. Correlation analysis pointed to a link between these miRNAs and RB/E2F and TP53 cascades with proproliferative effects, as corroborated by functional analyses. Finally, basal levels of miR-132 and miR-212 were measured in an independent cohort of 20 unstimulated CLL cases and both showed lower expression in progressive compared to stable patients, suggesting an association between the expression of these molecules and disease prognosis. Overall, our results support a model involving miR-132 and miR-212 upregulation in sustaining disease progression in CLL. These miRNAs may therefore provide new valuable strategies for therapeutic intervention.

Minimal residual disease after conventional treatment significantly impacts on progression-free survival of patients with follicular lymphoma: the FIL FOLL05 trial

PURPOSE

The role of the minimal residual disease (MRD) in follicular lymphoma is still debated. In this study, we assessed whether the BCL2/IGH rearrangement could have a prognostic role in patients receiving R-CHOP, R-FM, or R-CVP.

EXPERIMENTAL DESIGN

DNAs from 415 patients among the 504 cases enrolled in the FOLL05 trial (NCT00774826) were centralized and assessed for the BCL2/IGH at diagnosis, at the end of treatment, and after 12 and 24 months.

RESULTS

At diagnosis, the molecular marker was detected in 53% of cases. Patients without molecular marker or with a low molecular tumor burden (<1 × 10(-4) copies) showed higher complete remission (CR) rate and longer progression-free survival (PFS; 3-year PFS 80% vs. 59%; P = 0.015). PFS was significantly conditioned by the PCR status at 12 and 24 months, with 3-year PFS of 66% for MRD(-) cases versus 41% for those MRD(+) at 12 months (P = 0.015), and 84% versus 50% at 24 months (P = 0.014). The MRD negativity at 12 and 24 months resulted in an improved PFS both in CR and in partial remission (PR) patients (3-year PFS = 72% for cases CR/PCR(-) vs. 32% for those CR/PCR(+) vs. 62% for those PR/PCR(-) and 25% for patients in PR/PCR(+); P = 0.001). The prognostic value of MRD at 12 and 24 months of follow-up was confirmed also in multivariate analysis.

CONCLUSIONS

In this study, standardized molecular techniques have been adopted and applied on bone marrow samples from a large cohort. Data reported show that the MRD detection is a powerful independent predictor of PFS in patients with follicular lymphoma receiving conventional chemoimmunotherapy.