Outcomes with ibrutinib by line of therapy and post-ibrutinib discontinuation in patients with chronic lymphocytic leukemia: Phase 3 analysis

Defining treatment success in chronic lymphocytic leukemia: exploring surrogate markers, comorbidities, and patient-centered endpoints

INTRODUCTION

Traditionally, the success of chronic lymphocytic leukemia (CLL) treatment has been primarily assessed based on clinical outcomes, such as disease response, progression-free survival (PFS), and overall survival (OS). However, the evolution of treatment approaches recognizes the importance of a patient-centered perspective that includes factors directly affecting patients' quality of life and overall well-being.

AREAS COVERED

Studies addressing the impact of targeted agents on improving either OS or other endpoint surrogates were selected using PubMed and MEDLINE platforms. Our search also included studies that considered patient-centric endpoints such as health-related quality of life and patient-reported outcomes (PROs).

EXPERT OPINION

The changing landscape of CLL treatment underscores the importance of continually exploring various endpoints to thoroughly define treatment success. Beyond conventional metrics such as OS and surrogate endpoints, namely, PFS, time to next treatment (TTNT), and measurable residual disease (MRD) assessment, it becomes crucial to integrate enhanced comorbidity evaluations and patient-centered viewpoints into a CLL success roadmap.Subsequent investigations ought to concentrate on enhancing current surrogate endpoints, discerning their contextual significance, and exploring innovative indicators of treatment efficacy and safety. Given the dynamic nature of CLL and the heterogeneity among patient groups, personalized strategies are essential, taking into account individual traits and patient preferences.

Real-world analysis of adverse event rates after initiation of ibrutinib among Medicare beneficiaries with chronic lymphocytic leukemia

BACKGROUND

The first-generation BTK inhibitor ibrutinib is a standard-of-care therapy in the treatment of chronic lymphocytic leukemia (CLL) despite potential side effects that often lead to discontinuation.

METHODS

This study used 2013-2019 claims data to describe the incidence rate of adverse events (AEs) among elderly Medicare beneficiaries newly initiating ibrutinib for CLL.

RESULTS

The final sample contained 11,870 Medicare beneficiaries with CLL (mean age 77.2) newly initiating ibrutinib, of whom 65.2% discontinued over mean follow-up of 2.3 years. The overall incidence rate of AEs was 62.5 per 1000 patient-months for all discontinuers and 32.9 per 1000 patient-months for non-discontinuers. Discontinuers had a higher incidence rate of AEs per 1000 patient-months compared with non-discontinuers for all AEs examined, including infection (22.8 vs. 14.5), atrial fibrillation (15.1 vs. 7.0), anemia (21.9 vs. 14.5), and arthralgia/myalgia (19.5 vs. 13.6).

CONCLUSION

In this first real-world study of a national sample of elderly US patients treated with ibrutinib, we found a clear unmet need for improved management of ibrutinib-related AEs and/or new treatments to improve real-world outcomes in patients with CLL.

Real-world adherence and discontinuation among Medicare beneficiaries initiating venetoclax vs. BTKis in relapsed/refractory chronic lymphocytic leukemia

The treatment landscape for chronic lymphocytic leukemia (CLL) has been transformed by the availability of Bruton's tyrosine kinase inhibitors (BTKis) and the B-cell lymphoma 2 (BCL-2) inhibitor venetoclax. Despite clinical trial data supporting these novel oral agents, evidence evaluating real-world adherence is limited. This study used 2015-2019 Medicare claims data for elderly patients with relapsed/refractory CLL to assess differences in real-world adherence and discontinuation in the 12 months after treatment initiation. In the final sample of 711 venetoclax patients and 1,566 BTKi patients, we found that those initiating venetoclax tended to be younger (mean age 75.6 [SD 6.0] vs 77.6 [SD 6.9] years, p < .001) but had poorer clinical characteristics. After risk-adjustment, the venetoclax group had higher adherence (61.9% vs. 45.4%, p < .0001) and lower discontinuation when compared to the BTKi group (28.5% vs. 47.4%, p < .001). These favorable real-world findings underscore the importance of developing well-tolerated novel combinations for older adults.

Ibrutinib discontinuation and associated factors in a real-world national sample of elderly Medicare beneficiaries with chronic lymphocytic leukemia

Prior studies evaluating ibrutinib discontinuation are limited to clinical trials and selected medical centers and hence may not reflect real-world practice. This study used Medicare claims (2013-2019) to examine ibrutinib discontinuation and associated factors among elderly patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). Over a median follow-up of 2.1 years, two-thirds (65.2%) of the 11,870 new ibrutinib initiators were discontinued, with half (45.1%) of patients discontinuing within 12 months of initiation. Factors such as advanced age, lack of Part D low-income subsidy, evidence of prior CLL/SLL treatment, and cardiovascular comorbidities (e.g. atrial fibrillation) were associated with higher risk of discontinuation. Over a median of 1.2 years from discontinuation, 40% of discontinuers initiated another CLL/SLL treatment after ibrutinib discontinuation; 25% of patients restarted ibrutinib treatment at some point over follow-up. Our findings point to a large unmet need with the widely used BTKi ibrutinib and underscore the importance of ongoing development of efficacious and well-tolerated CLL/SLL therapies.

Richter Transformation of Chronic Lymphocytic Leukemia-Are We Making Progress?

PURPOSE OF REVIEW

The treatment paradigm of chronic lymphocytic leukemia (CLL) has dramatically changed with the advent of novel targeted agents over the past decade. Richter transformation (RT), or the development of an aggressive lymphoma from a background of CLL, is a well-recognized complication of CLL and carries significantly poor clinical outcomes. Here, we provide an update on current diagnostics, prognostication, and contemporary treatment of RT.

RECENT FINDINGS

Several genetic, biologic, and laboratory markers have been proposed as candidate risk factors for the development of RT. Although a diagnosis of RT is typically suspected based on clinical and laboratory findings, tissue biopsy is essential for histopathologic confirmation of diagnosis. The standard of care for RT treatment at this time remains chemoimmunotherapy with the goal of proceeding to allogeneic stem cell transplantation in eligible patients. Several newer treatment modalities are being studied for use in the management of RT, including small molecules, immunotherapy, bispecific antibodies, and chimeric antigen receptor T-cell (CAR-T) therapy. The management of patients with RT remains a challenge. Ongoing trials show enormous promise for newer classes of therapy in RT, with the hope being that these agents can synergize, and perhaps supersede, the current standard of care in the near future.

Population-level impact of ibrutinib for chronic lymphocytic leukemia in British Columbia, Canada

Ibrutinib has dramatically changed the treatment landscape for chronic lymphocytic leukemia (CLL) since its availability in British Columbia (BC), Canada in 2014. We analyzed patterns of use and real-world survival outcomes in 370 patients who received ibrutinib for first-line (1 L, n = 35) and relapsed/refractory (R/R, n = 335) CLL between 2014-2018 in BC. Dose reductions and interruptions were frequent in 32% and 27%, respectively. With a median follow-up of 27.6 months, 35% of patients discontinued ibrutinib, primarily for adverse events (AEs) rather than progressive disease. Over the course of treatment, 87% of patients experienced at least one adverse event. The 2-year overall survival (OS) and event-free survival (EFS) were excellent at 83.9% and 76.1%, respectively, with medians not reached. However, patients who discontinued ibrutinib had a median OS of 32.5 months and median EFS of only 3.8 months from time of discontinuation, highlighting the need to minimize toxicity in the real-world.

Real-World Clinical Outcomes and Adverse Events in Patients with Chronic Lymphocytic Leukemia Treated with Ibrutinib: A Single-Center Retrospective Study

Background and Objectives: The treatment of chronic lymphocytic leukemia (CLL) has acquired new targeted therapies. In clinical trials, ibrutinib improved outcomes safely. Real-world data called for a reappraisal of ibrutinib strategies. We report on a single center's experience with ibrutinib monotherapy, aiming to explore the outcomes, tolerability, and prognosis of CLL patients in routine clinical practice. Materials and Methods: Data were collected from all CLL patients treated with ibrutinib at Fundeni Clinical Institute, Bucharest, Romania, between January 2016 and June 2021. Results: A total of one hundred twenty-three CLL adult patients were treated with ibrutinib. Of the patients, 87% had relapsed/refractory CLL. The median age at ibrutinib initiation was 65 years; 44.7% of patients were staged Rai III/IV. At 32-month median follow-up, the median progression-free survival (PFS) was 50 months, the overall survival (OS) was not reached, and the overall response rate (ORR) was 86.2%. The age or number of previous therapies did not impact outcomes or tolerability. An Eastern Cooperative Oncology Group performance status (ECOG PS) score ≥ 2 and shorter time from initiation of last therapy (TILT) before ibrutinib predicted inferior PFS. Baseline characteristics had no impact on the OS except for TILT in R/R CLL patients. Drug-related adverse events (AEs) of any grade and grade ≥ 3 AEs were reported in 82.1% and 30.9% of the patients, respectively. Infections were the most common AEs (29.3%). Drug discontinuation was permanent in 43.9% of patients, mainly due to disease progression (17.1%) and toxicity (8.9%). Patients with a Cumulative Illness Rating Scale (CIRS) score ≥ 6 had a higher risk for toxicity-related discontinuation. An ECOG PS ≥ 2 predicted an increased rate of permanent discontinuation and grade ≥ 3 AEs. Conclusions: The outcomes of this study align with the results from ibrutinib clinical trials. Our study demonstrated that poor patient fitness, early relapse before ibrutinib, and permanent ibrutinib discontinuation are essential outcome determinants. Patient comorbidity burden and fitness were significant predictors for ibrutinib intolerance.

Pevonedistat, a Nedd8-activating enzyme inhibitor, in combination with ibrutinib in patients with relapsed/refractory B-cell non-Hodgkin lymphoma

Pevonedistat (TAK924) is a Nedd8-activating enzyme inhibitor with preclinical activity in non-Hodgkin lymphoma (NHL). This open-label, Phase I, multicenter, investigator-sponsored study enrolled patients with relapsed/refractory (R/R) NHL and chronic lymphocytic leukemia (CLL). The primary objective was safety. Pevonedistat was given intravenously on days 1, 3, 5 of a 21-day cycle for 8 cycles at five dose levels (15 to 50 mg/m2); ibrutinib was administered at 420 or 560 mg orally daily continuously. Eighteen patients with NHL were enrolled, including 8 patients with mantle cell lymphoma (MCL) and 4 patients with CLL. One dose-limiting toxicity (mediastinal hemorrhage) occurred at 50 mg/m2 of pevonedistat which is the estimated maximum tolerated dose. Bruising and diarrhea were the most common adverse events (56% and 44%). Atrial fibrillation occurred in 3 patients (17%). Grade ≥3 toxicities included arthralgia, atrial fibrillation, bone pain, diarrhea, hypertension, and mediastinal hemorrhage (one patient each). The overall response rate (ORR) was 65% (100% ORR in MCL). Pevonedistat disposition was not modified by ibrutinib. scRNA-Seq analysis showed that pevonedistat downregulated NFκB signaling in malignant B-cells in vivo. Thus, pevonedistat combined with ibrutinib demonstrated safety and promising early efficacy in NHL and CLL. NAE inhibition downregulated NFκB signaling in vivo.

Resistance to Bruton tyrosine kinase inhibition in chronic lymphocytic leukaemia and non-Hodgkin lymphoma

Bruton tyrosine kinase inhibitors (BTKi) have transformed the therapeutic landscape of chronic lymphocytic leukaemia (CLL) and non-Hodgkin lymphoma. However, primary and acquired resistance to BTKi can be seen due to a variety of mechanisms including tumour intrinsic and extrinsic mechanisms such as gene mutations, activation of bypass signalling pathways and tumour microenvironment. Herein, we provide an updated review of the key clinical data of BTKi treatment in CLL, mantle cell lymphoma, and diffuse large B-cell lymphoma (DLBCL). We incorporate the most recent findings regarding mechanisms of resistance to covalent and non-covalent inhibitors, including ibrutinib, acalabrutinib, zanubrutinib and pirtobrutinib. We also cover the clinical sensitivity of certain molecular subtypes of DLBCL to an ibrutinib-containing regimen. Lastly, we summarise ongoing clinical investigations aimed at overcoming resistance via use of BTKi-containing combined therapies or the novel non-covalent BTKi. The review article targets an audience of clinical practitioners, clinical investigators and translational researchers.

Zanubrutinib Monotherapy for Naïve and Relapsed/Refractory Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma: A Pooled Analysis of Three Studies

INTRODUCTION

Zanubrutinib is a highly selective irreversible inhibitor of Bruton tyrosine kinase which has shown significant activity in lymphoid malignancies in early phase studies. We report here the long-term follow-up outcomes of zanubrutinib in various lines of therapy in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL).

METHODS

This post hoc analysis pooled patients with treatment-naïve (TN) or relapsed/refractory (R/R) CLL/SLL receiving zanubrutinib monotherapy from three phase 1/2 studies (BGB-3111-1002, BGB-3111-AU-003, BGB-3111-205).

RESULTS

A total of 211 patients with CLL/SLL (TN 19, R/R 192) were included. After weighting (TN 19, R/R 24), the overall response rate (ORR) was 95.4% and significantly higher in the TN group than in the R/R group (100 vs. 91.0%, p < 0.0001). ORR was also significantly higher in the TN group than in the one prior line of therapy group (100 vs. 98.9%, p < 0.0001). Among those with R/R disease, the ORR was 97.8% in patients with one prior line of therapy (n = 79) and 90.7% in those with > 1 prior lines of therapy (n = 85; p = 0.080). The median follow-up times were 50.1, 35.7, and 45.9 months for TN, R/R and all cohorts, respectively. Progression-free survival and overall survival were significantly longer in the TN group and only one prior line of therapy group compared with the > 1 prior lines of therapy group (all p < 0.05) and were similar in the TN group compared with the one prior line therapy group. Efficacy was similar regardless of the presence of genomic aberrations. Most frequent grade ≥ 3 adverse events were infections (41.7%), neutropenia (34.1%), and thrombocytopenia (9.4%). Atrial fibrillation occurred in only 1.9% of patients.

CONCLUSIONS

With extended follow-up, zanubrutinib yielded long-term benefits and demonstrated a favorable safety profile for patients with TN or RR CLL/SLL. Earlier utilization of zanubrutinib was associated with better outcomes.

TRIAL REGISTRATION

Clinical Trials.gov identifiers, NCT03189524, NCT02343120 (retrospectively registered), and NCT03206918 (retrospectively registered).

Real-World Characteristics and Outcome of Patients Treated With Single-Agent Ibrutinib for Chronic Lymphocytic Leukemia in Spain (IBRORS-LLC Study)

BACKGROUND

Ibrutinib demonstrated remarkable efficacy and favorable tolerability in patients with untreated or relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL), including those with high-risk genetic alterations. The IBRORS-CLL study assessed the characteristics, clinical management and outcome of CLL patients receiving ibrutinib in routine clinical practice in Spain.

PATIENTS

Observational, retrospective, multicenter study in CLL patients who started single-agent ibrutinib as first-line treatment or at first or second relapse between January 2016 and January 2019.

RESULTS

A total of 269 patients were included (median age: 70.9 years; cardiovascular comorbidity: 55.4%, including hypertension [47.6%] and atrial fibrillation [AF] [7.1%]). Overall, 96.7% and 69% of patients underwent molecular testing for del(17p)/TP53 mutation and IGHV mutation status. High-risk genetic features included unmutated IGHV (79%) and del(17p)/TP53 mutation (first-line: 66.3%; second-line: 23.1%). Overall, 84 (31.2%) patients received ibrutinib as first-line treatment, and it was used as second- and third-line therapy in 121 (45.0%) and 64 (23.8%) patients. The median progression-free survival and overall survival were not reached irrespective of del(17p)/TP53, or unmutated IGHV. Common grade ≥3 adverse events were infections (12.2%) and bleeding (3%). Grade ≥3 AF occurred in 1.5% of patients.

CONCLUSION

This real-world study shows that single-agent ibrutinib is an effective therapy for CLL, regardless of age and high-risk molecular features, consistent with clinical trials. Additionally, single-agent ibrutinib was well tolerated, with a low rate of cardiovascular events. This study also emphasized a high molecular testing rate of del(17p)/TP53 mutation and IGHV mutation status in clinical practice according to guideline recommendations.

Prognostic Impact and Risk Factors of Infections in Patients with Chronic Lymphocytic Leukemia Treated with Ibrutinib

Ibrutinib represents extraordinary progress in the treatment of chronic lymphocytic leukemia (CLL). However, treatment-related adverse events limit the benefit of this agent. This observational, multicenter study focused on the incidence, risk factors, and prognostic impact of infections in 494 patients with CLL treated with an ibrutinib-based treatment. Ibrutinib was given to 89 (18%) previously untreated patients (combined with rituximab, 24) and 405 (82%) relapsed/refractory patients. Pneumonia (PN), grade ≥3 non-opportunistic infections (NOI), and opportunistic infections (OI) were recorded in 32% of patients with an overall incidence rate per 100 person-year of 15.3% (PN, 10%; NOI, 3.3%; OI, 2%). Infections were the reason for the permanent discontinuation of ibrutinib in 9% of patients. Patients who experienced pneumonia or a severe infection showed a significantly inferior survival than those who were infection-free (p < 0.0001). A scoring system based on the three factors associated with a significant and independent impact on infections-PN or severe infection in the year before starting ibrutinib, chronic obstructive pulmonary disease, ≥2 prior treatments-identified patients with a two- to threefold increase in the rate of infections. In conclusion, the results of this study highlight the adverse impact of infectious events on the outcomes of CLL patients treated with ibrutinib.

Real-world Prescription Pattern, Discontinuation and Costs of Ibrutinib-Naïve Patients with Chronic Lymphocytic Leukemia: An Italian Healthcare Administrative Database Analysis

BACKGROUND AND OBJECTIVE

In order to integrate the existing and inconsistent information from clinical trials and real-world practice on chronic lymphocytic leukemia (CLL) treated with ibrutinib, this analysis aimed to describe the prescription pattern of new users of ibrutinib affected by CLL, focusing on discontinuation, severe adverse events (AEs) and change of treatment, and to assess the integrated healthcare expenditure from the Italian National Health System (INHS) perspective.

METHODS

Starting from the ReS database, adults with at least a supply of ibrutinib (ATC code L01XE27) were selected from 01/01/2016 to 12/31/2017. Those without any ibrutinib supply in the year before the index prescription were considered new users. Out of them, only patients with at least a primary or secondary in-hospital diagnosis of CLL (ICD-9-CM code 204.1*) from 01/01/2013 to 12/31/2018 were further broken down according to the ibrutinib's line treatment (first line-FL; second or later line-SLL) and analysed. They were characterized by sex and age in the selection period. Mean annual consumption (defined daily doses [DDD]), treatment discontinuation, changes of therapy, interruptions and healthcare costs in charge of the INHS were assessed during two follow-up years.

RESULTS

Out of more than 5 million inhabitants of the ReS database, 69 new ibrutinib users and diagnosed with CLL in 2016 (incidence: 1.6 × 100,000) and 41 in 2017 (incidence: 0.9 × 100,000) were selected. Of these, 21 (19.1%) were FL ibrutinib users and 89 (80.9%) were SLL ones, mostly males and with mean ages (±SD) of 65 ± 14 and 70 ± 10, respectively. The mean annual consumption among FL users decreased from 222.2 DDD per patient treated to 216.0 DDD, while increased among SLL patients from 238.6 DDD to 260.1 DDD, in the first and second follow-up year, respectively. The discontinuation rate was about 40% in the first year, similarly among FL and SLL users. SLL patients discontinued more frequently (52.8% vs 20.0%) in the second year. Very few AEs were recorded. The 62.5% of FL and 55.6% of SLL users discontinuing ibrutinib in 1-year follow-up, while one SLL patient (5.3%) in the second year changed therapy. The 20.0% and 15.9% of all new users in first and second year interrupted ibrutinib. The total integrated cost of FL patients was €55,732 reducing by about €15,000, while it was €58,716 for SLL ones decreasing by €6,000, respectively, in the first and in the second year. Pharmaceuticals were the key cost driver (ibrutinib accounted for more than 77%).

CONCLUSIONS

This analysis on Italian administrative data provided results about prescription patterns of ibrutinib FL and SLL new users with CLL, focusing on discontinuation, treatment change and healthcare costs over 2-year follow-up, and contributed to improve the knowledge on this hard-to-treat disease.

Current and future treatment strategies in chronic lymphocytic leukemia

Treatment decisions for patients with chronic lymphocytic leukemia (CLL) are dependent on symptoms and classification into high-, medium-, or low-risk categories. The prognosis for CLL hinges, in part, on the presence or absence of less-favorable genetic aberrations, including del(17p), del(11q), TP53 dysfunction, and IGHV mutations, as these markers are associated with worse treatment response. Promising results from multiple clinical trials show emerging therapies targeting Burton tyrosine kinase, B-cell leukemia/lymphoma 2, and phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit delta result in better outcomes and prolonged progression-free survival for patients both with and without certain high-risk aberrations. Favorable outcomes using these novel oral targeted therapies, either alone or in combination with other treatments such as anti-CD20 antibodies, has led to their use almost entirely supplanting chemoimmunotherapy in the treatment of CLL. In this narrative review, we summarize the current clinical evidence for the use of targeted mono- and combination therapies for CLL, discuss new and next-generation treatment approaches currently in development, and provide insight into areas of unmet need for the treatment of patients with CLL.

Cost-effectiveness of first-line vs third-line ibrutinib in patients with untreated chronic lymphocytic leukemia

The ALLIANCE A041202 trial found that continuously administered ibrutinib in the first-line setting significantly prolonged progression-free survival compared with a fixed-duration treatment of rituximab and bendamustine in older adults with chronic lymphocytic leukemia (CLL). In this study, we created a Markov model to assess the cost-effectiveness of ibrutinib in the first-line setting, compared with a strategy of using ibrutinib in the third-line after failure of time-limited bendamustine and venetoclax-based regimens. We estimated transition probabilities from randomized trials using parametric survival modeling. Lifetime direct health care costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) were calculated from a US payer perspective. First-line ibrutinib was associated with an improvement of 0.26 QALYs and 0.40 life-years compared with using ibrutinib in the third-line setting. However, using ibrutinib in the first-line led to significantly higher health care costs (incremental cost of $612 700), resulting in an ICER of $2 350 041 per QALY. The monthly cost of ibrutinib would need to be decreased by 72% for first-line ibrutinib therapy to be cost-effective at a willingness-to-pay threshold of $150 000 per QALY. In a scenario analysis where ibrutinib was used in the second-line in the delayed ibrutinib arm, first-line ibrutinib had an incremental cost of $478 823, an incremental effectiveness of 0.05 QALYs, and an ICER of $9 810 360 per QALY when compared with second-line use. These data suggest that first-line ibrutinib for unselected older adults with CLL is unlikely to be cost-effective under current pricing. Delaying ibrutinib for most patients with CLL until later lines of therapy may be a reasonable strategy to limit health care costs without compromising clinical outcomes.

Revisiting Richter transformation in the era of novel CLL agents

Richter transformation (RT) is the development of aggressive lymphoma - most frequently diffuse large B-cell lymphoma (DLBCL) and rarely Hodgkin lymphoma (HL) - arising on the background of chronic lymphocytic leukaemia (CLL). Despite recent advances in CLL treatment, RT also develops in patients on novel agents, usually occurring as an early event. RT incidence is lower in CLL patients treated with novel agents in the front line compared to relapsed/refractory cases, with a higher incidence in patients with TP53 disruption. The genetic heterogeneity and complexity are higher in RT-DLBCL than CLL; the genetics of RT-HL are largely unknown. In addition to TP53, aberrations in CDKN2A, MYC, and NOTCH1 are common in RT-DLBCL; however, no distinct RT-specific genetic aberration is recognised yet. RT-DLBCL on ibrutinib is frequently associated with BTK and PLCG2 mutations. Here, we update on genetic analysis, diagnostics and treatment options in RT in the era of novel agents.

The impact of early discontinuation/dose modification of venetoclax on outcomes in patients with relapsed/refractory chronic lymphocytic leukemia: post-hoc analyses from the phase III MURANO study

Fixed-duration venetoclax plus rituximab (VenR) has a manageable safety profile and improves survival in patients with relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL). We present data from the phase III MURANO study on the impact of venetoclax modification or premature discontinuation on outcomes in patients with R/R CLL. Time-dependent Cox proportional hazards regression models, stratified by 17p deletion and risk status, evaluated the impact of venetoclax discontinuation/modification on investigator-assessed progression-free survival (PFS) and overall survival (OS). Analyses were performed retrospectively (without type-1 error control) in intention-to-treat patients from the VenR arm of MURANO. Overall, 140/194 (72%) patients in the VenR arm completed 2 years of therapy; 54/194 (28%) patients prematurely discontinued treatment. Inferior PFS was observed in patients prematurely discontinuing venetoclax for any reason (disease progression excluded; p

Venetoclax Plus Rituximab in Relapsed Chronic Lymphocytic Leukemia: 4-Year Results and Evaluation of Impact of Genomic Complexity and Gene Mutations From the MURANO Phase III Study

PURPOSE

In previous analyses of the MURANO study, fixed-duration venetoclax plus rituximab (VenR) resulted in improved progression-free survival (PFS) compared with bendamustine plus rituximab (BR) in patients with relapsed or refractory chronic lymphocytic leukemia (CLL). At the 4-year follow-up, we report long-term outcomes, response to subsequent therapies, and the predictive value of molecular and genetic characteristics.

PATIENTS AND METHODS

Patients with CLL were randomly assigned to 2 years of venetoclax (VenR for the first six cycles) or six cycles of BR. PFS, overall survival (OS), peripheral-blood minimal residual disease (MRD) status, genomic complexity (GC), and gene mutations were assessed.

RESULTS

Of 389 patients, 194 were assigned to VenR and 195 to BR. Four-year PFS and OS rates were higher with VenR than BR, at 57.3% and 4.6% (hazard ratio [HR], 0.19; 95% CI, 0.14 to 0.25), and 85.3% and 66.8% (HR, 0.41; 95% CI, 0.26 to 0.65), respectively. Undetectable MRD (uMRD) at end of combination therapy (EOCT) was associated with superior PFS compared with low MRD positivity (HR, 0.50) and high MRD positivity (HR, 0.15). Patients in the VenR arm who received ibrutinib as their first therapy after progression (n = 12) had a reported response rate of 100% (10 of 10 evaluable patients); patients subsequently treated with a venetoclax-based regimen (n = 14) had a reported response rate of 55% (six of 11 evaluable patients). With VenR, the uMRD rate at end of treatment (EOT) was lower in patients with GC than in those without GC (P = .042); higher GC was associated with shorter PFS. Higher MRD positivity rates were seen with BIRC3 and BRAF mutations at EOCT and with TP53, NOTCH1, XPO1, and BRAF mutations at EOT.

CONCLUSION

Efficacy benefits with fixed-duration VenR are sustained and particularly durable in patients who achieve uMRD. Salvage therapy with ibrutinib after VenR achieved high response rates. Genetic mutations and GC affected MRD rates and PFS.

Current Treatment of Refractory/Relapsed Chronic Lymphocytic Leukemia: A Focus on Novel Drugs

Recently, the use of novel targeted drugs has changed the treatment paradigms in chronic lymphocytic leukemia (CLL). Among the several drugs used for the management of relapsed/refractory (R/R) CLL, Bruton tyrosine kinase inhibitors (ibrutinib and acalabrutinib), phosphatidylinositol 3-kinase inhibitors (idelalisib and duvelisib), B-cell lymphoma 2 inhibitor (venetoclax), and novel CD20 monoclonal antibodies have demonstrated the greatest improvements in survival among R/R CLL patients. However, patients with relapsed but asymptomatic CLL do not need immediate alternative treatment and should be observed until evident sign of progression. Among available approved treatments, venetoclax + rituximab for 24 months or ibrutinib as continuous therapy is recommended. Another, less recommended, option is idelalisib in combination with rituximab. The correct treatment selection depends on the type of prior therapy, response to previous treatment and side effects, presence of comorbidities, and the risk of drug toxicity. Allogeneic hematopoietic stem cell transplantation and investigational therapies such as chimeric antigen receptor-T-cell therapy are promising treatment options for high-risk patients, including those progressing after 1 or more targeted therapies. The present review discusses current treatment strategies for patients with R/R CLL.

Proliferative Signals in Chronic Lymphocytic Leukemia; What Are We Missing?

Chronic lymphocytic leukemia (CLL) cells cycle between lymphoid tissue sites where they actively proliferate, and the peripheral blood (PB) where they become quiescent. Strong evidence exists for a crucial role of B cell receptor (BCR) triggering, either by (self-)antigen or by receptor auto-engagement in the lymph node (LN) to drive CLL proliferation and provide adhesion. The clinical success of Bruton's tyrosine kinase (BTK) inhibitors is widely accepted to be based on blockade of the BCR signal. Additional signals in the LN that support CLL survival derive from surrounding cells, such as CD40L-presenting T helper cells, myeloid and stromal cells. It is not quite clear if and to what extent these non-BCR signals contribute to proliferation in situ. In vitro BCR triggering, in contrast, leads to low-level activation and does not result in cell division. Various combinations of non-BCR signals delivered via co-stimulatory receptors, Toll-like receptors (TLRs), and/or soluble cytokines are applied, leading to comparatively modest and short-lived CLL proliferation in vitro. Thus, an unresolved gap exists between the condition in the patient as we now understand it and applicable knowledge that can be harnessed in the laboratory for future therapeutic applications. Even in this era of targeted drugs, CLL remains largely incurable with frequent relapses and emergence of resistance. Therefore, we require better insight into all aspects of CLL growth and potential rewiring of signaling pathways. We aim here to provide an overview of in vivo versus in vitro signals involved in CLL proliferation, point out areas of missing knowledge and suggest future directions for research.

Resistance Mechanisms to Targeted Agents in Chronic Lymphocytic Leukemia

Agents that specifically target pathologic mechanisms of survival have now been approved for the treatment of chronic lymphocytic leukemia in both the treatment-naive and relapsed/refractory settings. These 4 agents include the Bruton tyrosine kinase inhibitor ibrutinib, the B-cell leukemia/lymphoma-2 inhibitor venetoclax, and the phosphatidylinositol-3 kinase inhibitors idelalisib and duvelisib. Although clinical outcomes are improved with all of these inhibitors, acquired resistance does occur and leads to progression of disease. Resistance to targeted therapy can occur through direct mutations of the target or through the overexpression of alternative cell survival pathways not affected by the specific inhibitor. Determining which patients will develop resistance, why resistance occurs, how to overcome resistance, and when to test for resistance are all subjects of ongoing research. In this review, we describe the current data relative to the development of resistance to targeted therapies in CLL.

How We Manage Patients With Chronic Lymphocytic Leukemia During the SARS-CoV-2 Pandemic

Infections are a major cause of morbidity and mortality in patients with chronic lymphocytic leukemia (CLL). These can be exacerbated by anti-leukemic treatments. In addition, the typical patients with CLL already have fragilities and background risk factors that apply to the general population for severe COVID-19. On these bases, patients with CLL may experience COVID-19 morbidity and mortality. Recurrent seasonal epidemics of SARS-CoV-2 are expected, and doctors taking care of patients with CLL must be prepared for the possibility of substantial resurgences of infection and adapt their approach to CLL management accordingly. In this Guideline Article, we aim at providing clinicians with a literature-informed expert opinion on the management of patients with CLL during SARS-CoV-2 epidemic.

Exploring a Future for PI3K Inhibitors in Chronic Lymphocytic Leukemia

PURPOSE OF REVIEW

Treatment for chronic lymphocytic leukemia has changed substantially in the past decade with an increasing shift towards use of targeted therapies, in particular agents targeting the B cell receptor pathway. Inhibition of PI3K, downstream of the B cell receptor pathway, represents an active therapeutic strategy in CLL. Here, we explore the relevance of PI3K inhibition in CLL, examine efficacy and toxicity of approved PI3K inhibitors in CLL, examine barriers to use of PI3K inhibitors, and explore strategies to optimize use of PI3K inhibitors in CLL.

RECENT FINDINGS

Current generation PI3K inhibitors are active agents in CLL but their use may be limited by immune-mediated toxicities. Clinical trials of next generation PI3K inhibitors are ongoing and early data suggests these agents are highly active with potentially differentiated toxicity profiles. Furthermore, alternative dosing schedules may reduce toxicities of these agents. Inhibition of PI3K remains an important strategy in management of CLL and novel approaches to limit toxicities of PI3K inhibitors represent an important area of clinical research in CLL.

Outcomes with ibrutinib by line of therapy and post-ibrutinib discontinuation in patients with chronic lymphocytic leukemia: Phase 3 analysis

The efficacy of ibrutinib has been demonstrated in patients with chronic lymphocytic leukemia (CLL), including as first‐line therapy. However, outcomes after ibrutinib discontinuation have previously been limited to higher‐risk populations with relapsed/refractory (R/R) disease. The objective of this study was to evaluate outcomes of ibrutinib‐treated patients based on prior lines of therapy, including after ibrutinib discontinuation. Data were analyzed from two multicenter phase 3 studies of single‐agent ibrutinib: RESONATE (PCYC‐1112) in patients with R/R CLL and RESONATE‐2 (PCYC‐1115) in patients with treatment‐naive (TN) CLL without del(17p). This integrated analysis included 271 ibrutinib‐treated non‐del(17p) patients with CLL (136 TN and 135 R/R). Median progression‐free survival (PFS) was not reached for subgroups with 0 and 1/2 prior therapies but was 40.6 months for patients with ≥3 therapies (median follow‐up: TN, 36 months; R/R, 44 months). Median overall survival (OS) was not reached in any subgroup. Overall response rate (ORR) was 92% in TN and 92% in R/R, with depth of response increasing over time. Adverse events (AEs) and ibrutinib discontinuation due to AEs were similar between patient groups. Most patients (64%) remain on treatment. OS following discontinuation was 9.3 months in R/R patients (median follow‐up 18 months, n = 51) and was not reached in TN patients (median follow‐up 10 months, n = 30). In this integrated analysis, ibrutinib was associated with favorable PFS and OS, and high ORR regardless of prior therapies in patients with CLL. The best outcomes following ibrutinib discontinuation were for patients receiving ibrutinib in earlier lines of therapy.