Minimal Residual Disease Dynamics after Venetoclax-Obinutuzumab Treatment: Extended Off-Treatment Follow-up From the Randomized CLL14 Study

First-Line Venetoclax Combinations in Chronic Lymphocytic Leukemia

BACKGROUND

Randomized trials of venetoclax plus anti-CD20 antibodies as first-line treatment in fit patients (i.e., those with a low burden of coexisting conditions) with advanced chronic lymphocytic leukemia (CLL) have been lacking.

METHODS

In a phase 3, open-label trial, we randomly assigned, in a 1:1:1:1 ratio, fit patients with CLL who did not have TP53 aberrations to receive six cycles of chemoimmunotherapy (fludarabine-cyclophosphamide-rituximab or bendamustine-rituximab) or 12 cycles of venetoclax-rituximab, venetoclax-obinutuzumab, or venetoclax-obinutuzumab-ibrutinib. Ibrutinib was discontinued after two consecutive measurements of undetectable minimal residual disease or could be extended. The primary end points were undetectable minimal residual disease (sensitivity, <10^-4 [i.e., <1 CLL cell in 10,000 leukocytes]) as assessed by flow cytometry in peripheral blood at month 15 and progression-free survival.

RESULTS

A total of 926 patients were assigned to one of the four treatment regimens (229 to chemoimmunotherapy, 237 to venetoclax-rituximab, 229 to venetoclax-obinutuzumab, and 231 to venetoclax-obinutuzumab-ibrutinib). At month 15, the percentage of patients with undetectable minimal residual disease was significantly higher in the venetoclax-obinutuzumab group (86.5%; 97.5% confidence interval [CI], 80.6 to 91.1) and the venetoclax-obinutuzumab-ibrutinib group (92.2%; 97.5% CI, 87.3 to 95.7) than in the chemoimmunotherapy group (52.0%; 97.5% CI, 44.4 to 59.5; P<0.001 for both comparisons), but it was not significantly higher in the venetoclax-rituximab group (57.0%; 97.5% CI, 49.5 to 64.2; P = 0.32). Three-year progression-free survival was 90.5% in the venetoclax-obinutuzumab-ibrutinib group and 75.5% in the chemoimmunotherapy group (hazard ratio for disease progression or death, 0.32; 97.5% CI, 0.19 to 0.54; P<0.001). Progression-free survival at 3 years was also higher with venetoclax-obinutuzumab (87.7%; hazard ratio for disease progression or death, 0.42; 97.5% CI, 0.26 to 0.68; P<0.001), but not with venetoclax-rituximab (80.8%; hazard ratio, 0.79; 97.5% CI, 0.53 to 1.18; P = 0.18). Grade 3 and grade 4 infections were more common with chemoimmunotherapy (18.5%) and venetoclax-obinutuzumab-ibrutinib (21.2%) than with venetoclax-rituximab (10.5%) or venetoclax-obinutuzumab (13.2%).

CONCLUSIONS

Venetoclax-obinutuzumab with or without ibrutinib was superior to chemoimmunotherapy as first-line treatment in fit patients with CLL. (Funded by AbbVie and others; GAIA-CLL13 ClinicalTrials.gov number, NCT02950051; EudraCT number, 2015-004936-36.).

An update on the efficacy of Venetoclax for chronic lymphocytic leukemia

INTRODUCTION

The BCL2 inhibitor venetoclax has dramatically changed the treatment of chronic lymphocytic leukemia (CLL) and has introduced the concept of time-limited therapy with targeted agents.

AREAS COVERED

This review discusses the mechanism of action of venetoclax, adverse effects, and the clinical data with this agent as identified by a selective search of clinical trials in the PubMed database. Venetoclax is FDA-approved with anti-CD20 monoclonal antibodies; however, research is ongoing evaluating its efficacy when given in combination with other agents, such as the Bruton's Tyrosine Kinase (BTK) inhibitors.

EXPERT OPINION

Venetoclax-based therapy is an excellent treatment option for patients interested in time-limited therapy and can be offered in both the front-line and relapsed/refractory settings. Tumor lysis syndrome (TLS) risk evaluation, preventative measures, and strict monitoring should be conducted, while these patients ramp up to target dose. Venetoclax-based therapies produce deep and durable responses with patients often achieving undetectable measurable residual disease (uMRD). This has led to a discussion of MRD-driven, finite-duration treatment approaches, although longer term data is still needed. While many patients eventually lose uMRD status, re-treatment with venetoclax remains an area of interest with promising results. Mechanisms of resistance to venetoclax are being elucidated, and research is ongoing.

Transcriptomic profiles and 5-year results from the randomized CLL14 study of venetoclax plus obinutuzumab versus chlorambucil plus obinutuzumab in chronic lymphocytic leukemia

Data on long-term outcomes and biological drivers associated with depth of remission after BCL2 inhibition by venetoclax in the treatment of chronic lymphocytic leukemia (CLL) are limited. In this open-label parallel-group phase-3 study, 432 patients with previously untreated CLL were randomized (1:1) to receive either 1-year venetoclax-obinutuzumab (Ven-Obi, 216 patients) or chlorambucil-Obi (Clb-Obi, 216 patients) therapy (NCT02242942). The primary endpoint was investigator-assessed progression-free survival (PFS); secondary endpoints included minimal residual disease (MRD) and overall survival. RNA sequencing of CD19-enriched blood was conducted for exploratory post-hoc analyses. After a median follow-up of 65.4 months, PFS is significantly superior for Ven-Obi compared to Clb-Obi (Hazard ratio [HR] 0.35 [95% CI 0.26-0.46], p < 0.0001). At 5 years after randomization, the estimated PFS rate is 62.6% after Ven-Obi and 27.0% after Clb-Obi. In both arms, MRD status at the end of therapy is associated with longer PFS. MRD + ( ≥ 10-4) status is associated with increased expression of multi-drug resistance gene ABCB1 (MDR1), whereas MRD6 (< 10-6) is associated with BCL2L11 (BIM) expression. Inflammatory response pathways are enriched in MRD+ patient solely in the Ven-Obi arm. These data indicate sustained long-term efficacy of fixed-duration Ven-Obi in patients with previously untreated CLL. The distinct transcriptomic profile of MRD+ status suggests possible biological vulnerabilities.

Sequencing and combination of current small-molecule inhibitors for chronic lymphocytic leukemia: Where is the evidence?

Small-molecule inhibitors have revolutionized the treatment of chronic lymphocytic leukemia (CLL), a landscape once dominated by chemoimmunotherapy (i.e., an anti-CD20 monoclonal antibody in combination with systemic chemotherapy) in fit and unfit individuals. Key challenges include the management of refractory disease as well as the optimization of the therapy sequence. Decreased responsiveness has been observed with prolonged treatment, especially with Bruton tyrosine kinase (BTK) and phosphatidylinositol 3-kinase (PI3K) inhibitors which are given continuously, while venetoclax, an agent that targets dysregulations in intrinsic apoptosis signaling, has a fixed duration when combined with anti-CD20 monoclonal antibodies or BTK inhibitors. Combination therapy aims to synergistically target different oncogenic signaling pathways to abrogate the proliferation of resistant clones and thereby allows for fixed-duration treatments. An advantage of fixed-duration therapy is the potential to decrease financial and drug-induced toxicities. Sequencing of therapies is important to individualize treatment decisions based on factors such as age, comorbidities, tolerability, and patient preferences. However, to date, there are limited data to guide the rational sequencing or combination of these therapies, since conventional chemoimmunotherapy or chemotherapy regimens were used as comparators against these small-molecule inhibitors in trials that led to their regulatory approvals. In this article, we examined and evaluated the current evidence for sequencing versus the combination of small-molecule inhibitors for CLL by conducting comprehensive searches of the United States National Library of Medicine PubMed database, key meeting abstracts, and clinical practice guidelines. We also summarized findings from expert opinions to elucidate best practices for clinical scenarios with limited evidence to guide treatment selection.

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.

Front-line fludarabine-cyclophosphamide-rituximab (FCR) in 110 patients with chronic lymphocytic leukaemia (CLL): real-life experience with long-term outcomes, toxicities and responses to second-line therapies

Fludarabine-cyclophosphamide-rituximab (FCR) has been the gold standard front-line treatment for fit CLL patients until novel agent's introduction. Decision between either time-limited FCR or "endless" Bruton's tyrosine kinase inhibitor (BTKi) therapy may be difficult in fit IGHV-mutated-non-TP53 cases. We describe the outcomes after front-line FCR in 110 CLL patients from 5 centres in Catalonia, Spain, over a period of more than 10 years. ORR was 96.3% and CR 74.5%. Median second-treatment free survival (TFS1) was 6.2 years and median OS was 10.8 years. 50 (45.5%) patients required a subsequent therapy. Median third-treatment free survival was better for BTKi than for chemotherapy ± antiCD20 strategies (not reached vs 3.1 years, p = 0.003). Only 50 (45.5%) patients completed 6 cycles of FCR, and the main reason for discontinuation was cytopenia 29 (26.4%). 15 (13.6%) patients developed a second cancer, and 5 (4.5%) patients experienced a Richter's transformation (RT). At the end of follow-up, 50 (45.5%) patients remained in CR. Response rates, TFS1, OS, RT, and second cancers did not differ between patients treated with 6 vs 4 cycles of FCR. In conclusion, front-line FCR treatment leads to very long CR in almost half of patients, and BTKi yields excellent outcomes in relapsed patients.

Canadian evidence-based guideline for frontline treatment of chronic lymphocytic leukemia: 2022 update

Chronic lymphocytic leukemia (cll) is the most common adult leukemia in North America. In 2018, the first unified national guideline in Canada was developed for the front-line treatment of cll that helped guide treatment across the country. As an update in 2022, a group of clinical experts from across Canada came together to provide input and guidance that included new and innovative treatments and approaches that will continue to provide health care professionals with clear guidance on the first-line management of cll. Recommendations were provided in consensus based on available evidence for the first-line treatment of cll.

Treatment of Richter's syndrome

Richter's syndrome (RS) is an aggressive histologic transformation of chronic lymphocytic leukemia (CLL), most commonly to diffuse large B-cell lymphoma (DLBCL). Outcomes are generally poor, with complete remission (CR) rates of only about 20% and less than 20% long-term survival with chemoimmunotherapy (CIT). RS is biologically heterogeneous, and in 80% of patients with CLL who develop DLBCL, the disease is clonally related to the CLL. Clonally unrelated cases are genetically and immunologically distinct from clonally related DLBCL-RS, have more favorable responses to CIT, and are best treated as de novo DLBCL. Relatively favorable outcomes with CIT are also seen in patients who have never previously received treatment for CLL and who lack TP53 mutation or deletion. For the remaining patients, treatment on a clinical trial is optimal. Fortunately, numerous agents are now in clinical development that show encouraging results. Here we review clinical data for some of the most promising approaches. DLBCL-RS tumor cells frequently express programmed cell death 1 protein (PD-1), and several studies have demonstrated activity for PD-1 inhibitors, especially in combination with ibrutinib. The BCL2 inhibitor venetoclax in combination with R-EPOCH CIT achieved CR in 50% of patients, and a study of venetoclax-R-CHOP is ongoing. The noncovalent Bruton's tyrosine kinase inhibitor pirtobrutinib has achieved responses in approximately two-thirds of heavily pretreated patients and, given its favorable toxicity profile, appears ideally suited to combining with other active agents. Finally, we review available data for bispecific antibodies, antibody-drug conjugates, and chimeric antigen receptor T-cell therapy, which, after revolutionizing the treatment of DLBCL, are now being evaluated in RS.

Selecting initial therapy in CLL

Targeted therapy is a powerful treatment option in chronic lymphocytic leukemia (CLL) that has outperformed conventional chemoimmunotherapy in most clinical settings. Except for selected young, fit patients with a mutated immunoglobulin heavy chain variable region gene, most patients benefit from targeted therapy with either a continuous BTK inhibitor or 1-year fixed-duration venetoclax-obinutuzumab as first-line treatment of CLL. Treatment selection is driven by patient-, treatment-, and disease-related factors, encompassing patient preference, concomitant medications, comorbidities, safety profile of the regimen, and TP53 aberration. Clinical trials are actively investigating the simultaneous inhibition of Bruton's tyrosine kinase (BTK) and B-cell lymphoma 2 (BCL-2) proteins with or without a CD20 monoclonal antibody, which can achieve deep response in most patients (52%-89% undetectable minimal residual disease in bone marrow).

Chronic lymphocytic leukemia treatment algorithm 2022

The treatment landscape for patients with chronic lymphocytic leukemia (CLL) has changed considerably with the introduction of very effective oral targeted therapies (such as Bruton tyrosine kinase inhibitors and venetoclax) and next-generation anti-CD20 monoclonal antibodies (such as obinutuzumab). These agents lead to improved outcomes in patients with CLL, even among those with high-risk features, such as del17p13 or TP53 mutation and unmutated immunoglobulin heavy chain (IGHV) genes. Selecting the right treatment for the right patient requires consideration of disease characteristics and prior treatment sequence, as well as patient preferences and comorbidities. The CLL-International Prognostic Index (CLL-IPI) remains the best-validated tool in predicting the time to first therapy among previously untreated patients, which guides selection for early intervention efforts. This review summarizes our current approach to the management of CLL, right from the time of diagnosis through relapsed disease.

Obinutuzumab plus chlorambucil versus ibrutinib in previously untreated chronic lymphocytic leukemia patients without TP53 disruptions: A real-life CLL campus study

One of the main issues in the treatment of patients with chronic lymphocytic leukemia (CLL) deals with the choice between continuous or fixed-duration therapy. Continuous ibrutinib (IB), the first-in-class BTK inhibitor, and obinutuzumab-chlorambucil (G-CHL) are commonly used therapies for elderly and/or comorbid patients. No head-to-head comparison has been carried out. Within the Italian campus CLL network, we performed a retrospective study on CLL patients without TP53 disruption treated with IB or G-CHL as first-line therapy. Patients in the G-CHL arm had a higher CIRS score and the worst renal function. The overall response rates between the G-CHL and IB arms were similar, but more complete remissions (CRs) were achieved with G-CHL (p = 0.0029). After a median follow-up of 30 months, the progression-free survival (PFS, p = 0.0061) and time to next treatment (TTNT, p = 0.0043), but not overall survival (OS, p = 0.6642), were better with IB than with G-CHL. Similar results were found after propensity score matching and multivariate analysis. While PFS and TTNT were longer with IB than with G-CHL in IGHV unmutated patients (p = 0.0190 and 0.0137), they were superimposable for IGHV mutated patients (p = 0.1900 and 0.1380). In the G-CHL arm, the depth of response (79% vs. 68% vs. 38% for CR, PR and SD/PD; p < 0.0001) and measurable residual disease (MRD) influenced PFS (78% vs. 53% for undetectable MRD vs. detectable MRD, p = 0.0203). Hematological toxicities were common in the G-CHL arm, while IB was associated with higher costs. Although continuous IB provides better disease control in CLL, IGHV mutated patients and those achieving an undetectable MRD show a marked clinical and economic benefit from a fixed-duration obinutuzumab-based treatment.

Management of front line chronic lymphocytic leukemia

Treatment options with targeted agents have changed the treatment landscape of CLL profoundly. Besides chemoimmunotherapy, treatment regimen approved for frontline therapy include continuous treatment with BTK inhibitors like ibrutinib and acalabrutinib or fixed-duration regimen like venetoclax-obinutuzumab with the approval of venetoclax-ibrutinib to be awaited. Although these agents have usually manageable side effects, toxicities might limit choices for the individual patient. We here discuss latest trial data and propose a treatment algorithm for frontline treatment of CLL according to fitness and relevant genetic risk factors like IGHV mutational status and TP53 aberrations.

MAJIC: a phase III trial of acalabrutinib + venetoclax versus venetoclax + obinutuzumab in previously untreated chronic lymphocytic leukemia or small lymphocytic lymphoma

Here we describe the rationale and design of MAJIC, a phase III, prospective, multicenter, randomized trial comparing the combination of the BTK inhibitor acalabrutinib plus the BCL2 inhibitor venetoclax versus the combination of venetoclax plus obinutuzumab as frontline treatment for chronic lymphocytic leukemia or small lymphocytic lymphoma. In both treatment arms, disease response (assessed by International Workshop on Chronic Lymphocytic Leukemia criteria) and minimal residual disease will be used to guide therapy duration, with all patients ultimately discontinuing treatment after a maximum of 2 years. The primary end point is progression-free survival. Key secondary end points include rates of undetectable minimal residual disease, overall response and overall survival. This study will address key unanswered questions in frontline chronic lymphocytic leukemia/small lymphocytic lymphoma therapy by investigating the optimal duration of finite treatment and identifying the optimal venetoclax doublet regimen.

Obinutuzumab, acalabrutinib, and venetoclax, after an optional debulking with bendamustine in relapsed or refractory chronic lymphocytic leukaemia (CLL2-BAAG): a multicentre, open-label, phase 2 trial

BACKGROUND

Although BTK inhibitors provide long-term disease-control in patients with chronic lymphocytic leukaemia, they need to be combined with BCL2 inhibitors or antibodies to achieve deep responses with undetectable minimal residual disease (uMRD), which allows for time-limited treatment. This trial aims to evaluate the triple combination of obinutuzumab, acalabrutinib, and venetoclax after an optional debulking with bendamustine.

METHODS

This multicentre, open-label, investigator-initiated, phase 2 study evaluates a sequential treatment consisting of a debulking with two cycles of bendamustine for patients with a higher tumour load (70 mg/m² intravenously on days 1 and 2, repeated after 28 days), followed by an induction and a maintenance with obinutuzumab (1000 mg intravenously on days 1-2, 8, and 15 of the first induction cycle, every 4 weeks in induction cycles 2-6 and every 12 weeks in the maintenance phase), acalabrutinib (100 mg orally twice daily continuously from induction cycle 2 day 1 onwards) and venetoclax (starting in induction cycle 3 with 20 mg per day with a weekly dose ramp-up over 5 weeks to the target dose of 400 mg per day). Eligible patients were aged 18 years or older with an ECOG performance score 0-2 and had relapsed or refractory chronic lymphocytic leukaemia requiring treatment according to the 2018 International Workshop on Chronic Lymphocytic Leukemia criteria. The primary endpoint was uMRD (<10^-4) in peripheral blood at the end of induction treatment assessed centrally at the final restaging, 12 weeks after the start of the last induction cycle. As per protocol, all patients with more than two induction cycles were included in the analyses. This study is registered with ClinicalTrials.gov, number NCT03787264, and is ongoing.

FINDINGS

Between Jan 14, 2019, and June 25, 2020, 45 evaluable patients with relapsed or refractory chronic lymphocytic leukaemia were enrolled; 13 (29%) were female, 32 (71%) were male, 21 (47%) had already received a targeted agent, and 14 (32%) had del(17)(p13.1) or TP53 mutation. Ethnicity-race data was not collected. At data cutoff (Feb 25, 2021), all patients had completed the induction treatment. 34 patients (76%; 95% CI 61-87, p=0·26) had uMRD in peripheral blood after 6 months of triple therapy. Until data cutoff, 32 (71%) patients started maintenance and nine (28%) were able to stop with uMRD. After a median observation time of 13·8 months (IQR 10·4-18·4), there were two (4%) Richter transformations, but no progressions and no deaths observed. The most common adverse events of grade 3 and 4 during the entire treatment were thrombocytopenia and neutropenia (12 [27%] of 45 patients each), tumour lysis syndrome and infections (five [11%] of 45 patients each, grade 3 adverse events only), infusion-associated reactions (four [9%] of 45 patients) and anaemia (four [9%] of 45 patients).

INTERPRETATION

With 76% of patients achieving uMRD in peripheral blood, this trial did not reach the prespecified activity threshold. Triple therapy with obinutuzumab, acalabrutinib, and venetoclax after an optional debulking with bendamustine regimen requires further evaluation in larger trials to define its value compared with double treatment with a BTK or BCL2 inhibitor combined with obinutuzumab or a combination of the two oral targeted drugs. Until these trials show a clear benefit, the use of the triple combination in routine practice cannot be recommended.

FUNDING

Acerta, AstraZeneca, F Hoffmann-La Roche, and AbbVie.

NCCN Guidelines® Insights: Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma, Version 3.2022

The treatment landscape of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) has significantly evolved in recent years. Targeted therapy with Bruton's tyrosine kinase (BTK) inhibitors and BCL-2 inhibitors has emerged as an effective chemotherapy-free option for patients with previously untreated or relapsed/refractory CLL/SLL. Undetectable minimal residual disease after the end of treatment is emerging as an important predictor of progression-free and overall survival for patients treated with fixed-duration BCL-2 inhibitor-based treatment. These NCCN Guidelines Insights discuss the updates to the NCCN Guidelines for CLL/SLL specific to the use of chemotherapy-free treatment options for patients with treatment-naïve and relapsed/refractory disease.

Long-term follow-up and future direction on the management of chronic lymphocytic leukemia/small lymphocytic leukemia

Objective

Chronic lymphocytic leukemia and small lymphocytic lymphoma remain the most prevalent adult leukemia in Western countries. Novel therapeutics have established long-term efficacy and have changed the landscape in patient management. In contrast, novel approaches pose opportunities for patients to be treated for finite durations. In this manuscript, we highlight long-term safety and efficacy data with Bruton's tyrosine kinase inhibitors and combination BCL2 + anti-CD20 therapies. We also offer key considerations for treatment selection and outline ongoing trials which may continue to expand therapeutic options and approaches.

Data sources

An electronic search of the PubMed database was performed to obtain key literature in chronic lymphocytic leukemia and small lymphocytic lymphoma published using the following search terms: chronic lymphocytic leukemia/small lymphocytic lymphoma, Richter syndrome, and histologic transformation. The search results were narrowed by selecting studies in humans published in English. Results were confined to the following article types: Clinical Trial, Phase II; Clinical Trial, Phase III; Clinical Trial, Phase IV; Guideline; Randomized Controlled Trial; Meta-Analysis; Systematic Reviews; and Validation Studies.

Data summary

Chronic lymphocytic leukemia and small lymphocytic lymphoma are different manifestations of the same disease and are managed in much the same way. Bruton's tyrosine kinase inhibitors have demonstrated long and durable efficacy benefits in patients with newly diagnosed chronic lymphocytic leukemia/small lymphocytic lymphoma and in the relapsed/refractory setting. Despite these benefits, long terms adverse events have posed challenges for patients and have led to treatment discontinuations. Additionally, the use of monotherapy Bruton's tyrosine kinase inhibitor's requires chronic use of the medications leading to added financial implications. BCL2 inhibition with venetoclax in combination with anti-CD20 monoclonal antibodies has offered a novel and finite treatment approach in frontline and relapsed chronic lymphocytic leukemia/small lymphocytic lymphoma. Ongoing clinical trials are in investigating this modality further to enhance durable responses utilizing a combination Bruton's tyrosine kinase inhibitor's and BCL2 inhibitors.

Conclusion

The treatment armamentarium of chronic lymphocytic leukemia/small lymphocytic lymphoma continues to evolve. Despite the long term, durable responses with Bruton's tyrosine kinase inhibitor's, it is likely that finite treatment durations could become the standard of care as a result of continued, long-term responses.

Immunoglobulin gene sequence analysis in chronic lymphocytic leukemia: the 2022 update of the recommendations by ERIC, the European Research Initiative on CLL

The somatic hypermutation (SHM) status of the clonotypic immunoglobulin heavy variable (IGHV) gene is a critical biomarker for assessing the prognosis of patients with chronic lymphocytic leukemia (CLL). Importantly, independent studies have documented that IGHV SHM status is also a predictor of responses to therapy, including both chemoimmunotherapy (CIT) and novel, targeted agents. Moreover, immunogenetic analysis in CLL has revealed that different patients may express (quasi)identical, stereotyped B cell receptor immunoglobulin (BcR IG) and are classified into subsets based on this common feature. Patients in certain stereotyped subsets display consistent biology, clinical presentation, and outcome that are distinct from other patients, even with concordant IGHV gene SHM status. All of the above highlights the relevance of immunogenetic analysis in CLL, which is considered a cornerstone for accurate risk stratification and clinical decision making. Recommendations for robust immunogenetic analysis exist thanks to dedicated efforts by ERIC, the European Research Initiative on CLL, covering all test phases, from the pre-analytical and analytical to the post-analytical, pertaining to the analysis, interpretation, and reporting of the findings. That said, these recommendations apply to Sanger sequencing, which is increasingly being superseded by next generation sequencing (NGS), further underscoring the need for an update. Here, we present an overview of the clinical utility of immunogenetics in CLL and update our analytical recommendations with the aim to assist in the refined management of patients with CLL.

Cellular Therapy in High-Risk Relapsed/Refractory Chronic Lymphocytic Leukemia and Richter Syndrome

Despite the development of highly effective, targeted inhibitors of B-cell proliferation and anti-apoptotic pathways in chronic lymphocytic leukemia (CLL), these treatments are not curative, and many patients will develop either intolerance or resistance to these treatments. Transformation of CLL to high-grade lymphoma—the so-called Richter syndrome (RS)—remains a highly chemoimmunotherapy-resistant disease, with the transformation occurring following targeted inhibitors for CLL treatment being particularly adverse. In light of this, cellular therapy in the form of allogenic stem cell transplantation and chimeric antigen receptor T-cell therapy continues to be explored in these entities. We reviewed the current literature assessing these treatment modalities in both high-risk CLL and RS. We also discussed their current limitations and place in treatment algorithms.